Fuel System for Boats

8/2/2019 Fuel System for Boats

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3 4 5z5 4

By Oave Gen

Course Number TI 501

WESTLAWN

FUEL SYSTEMS FOR BOATSTextOn

Institul e 01 Marine TechnologyeJo Mystic Seaport, PO Box 6000 ,75 Greenmanville Avenue, Mystic. CT 06355 USAwww.west/awn.edu

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Copyright 2007 by Dave GerrAIIrights Reserved.No part of this book maybe reproduced in any form without written permission from the author.

It is understood and agreed thatnothing expressed herein is intended to or shal l be eonstrued to giveany person,firm or eorporation any right, remedy or elaim against the author or any contributor; oragainst theWestlawnInstitute of Marine Teehnology, Ine. or any of its off ieers oremployees; or against the American Boat & Yacht

Couneil, Ine. or any of its offieers or employees.

Fuel Systems For Boa ts - Cou rse Number

Table OCContentsIntroduct ionRunning Pipe (Piping Schemat ics Overv iew)Double Your Fil ters- Doub le Your Fun (Duplex Fil ters )Sizing Up the FilterTo See Through or Not to SeeT hrough (Crear or Opaque Bow l Fi lters)Filter Height andLoc ationGas-Engine PipingDiesel Retur n-Line ComplicationsTwin -Tank Diesel Pip ingDistribution Man ifold (See also Appe ndix E, page 29)Diesel Day-Tank Pip ingByp ass Feed L inesFuel-Transfer PumpsMu ltiple TankSystemsPumps Suck (Pumps Should Operate InSuction)Cool Oil (Retum Oil Coo lers )Hot Oil (Oil -Filter Heaters)Fuel -Line ValvesRemoteFue l ShutoffsHold That Tank (TankWeights, Tank Chocks, TankFasten ing)Approximate FullTank Weights (Table)The Danger of Foam Burials (Tanks Encased In FoamNot Recommended)Aluminum -Strap Hold DownsCushi on Your Tank (Tank Padding)Welded-Dn TankAttachmentTankLocationFlexConnectors (Hose and Flexible Tube)Marine Fuel HoseTypesHol ding Hose (Hose Clamps)Tub ing SepcificationsAluminum Fuel PipingEliminating Spark s (Grou nding/Bond ing Tank s)Tank Openings and Penetrations (Where Allowed)Tank DrainsVent-a-Tank (Tank Vents)Vent-Run ConsiderationsVents Under Pressure (Vents for Tanks Filled Und er Pressure)Vent Spill Prevent ionFiII'er Up (TankFills)The Vetus Splash-StopSecurefillTaking Off (Tank Take-Off Fittings)Keeping YourTanks DryIt' s Baffling (Tank Baffle Installations and RequirementsDon't Share WallsRound the Com erTank LabelsTanks Under PressureTank Pressure RatingsLevel Gauging (Tank Level Guages)FloScan (Fuel Consumption Gauges)Tank Materials ................................... ........................................................................................................Fuel Tank Materials & Th icknesses (Table)Tanks Can't Be Used As StructureAlum inum-Tank Prese rvationGlass Tanks & Integral Tanks (Fiberglass Tanks)

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Fue l Systems For Boa tsFuel-System Design, Insta llatio n, and Specification

8)" Dave Gerrr , O 2007 Da n Gerr, Dra",'ings by the aut hor e eless etberwtse ncted{based on art id n for Pr ofessional Boatbu il du )Introducti onConsideringthe potential dangers. n's odd that there are sofew specificlegal requre rrents goveming bosystems. In fact, this IS serious bus iness. and 1'1 start off witha bang. The photoshows a 45-fool (13.7 mcruiser tha tbumedandsank in minutes as a rescrt of a fuel fire. This, by the way, was a de ser boat. Somad. as if diesel were fireproof . 11 is anything but. In tact . diesel fuel contains more energy per uni! volumeunil weighl than gascM loe. Though gasoline is much easer 10 ignite eoc can explode in !he rlght (cr wrongcondilions, once diesel getsbuming 's truly terrtfying.Diese l or gas, we 'l I take adetailed kx>k here at therequirementsfor sare. reliable ,andecen t fuel syslems.

Institul e 01 Morlne TechnologyWESTLAWN

For yecnts . !he only applicableUS Iaws apply 10 gas-enginevessels under the Code ofFede ral Regulations. IU callthisthe "CFR yachl " trom nowoo. 're find US legalrequirements for diesel-fuersystems. you have to look alpassenger-vessel regulatioosunder!he CFR jcr r -,K , andH-boats . T-boats (vesselsunder 100gross tons andcany ingless than 150passengers) areclosesttorecreaticnal vessets. I usetheT-boal regulat ions asa furtherguide for fuel system requrements. This 111 refer toas "CFR commercial." Though mandatory for passengvessels, these rulesare comptetey optionat for preasure craft.

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. .,...Fiberg lass Tank Construction ......................................................... 21Fiberglass Tank Wan Thic knesses 22TheBes t Tank Material (Polyethylene) .......................................... 22Fiberglass Gasoline Tanks are Damaged by Ethanol... 22aOon't Go Rubbery and Don'tSplit! (Don 't Use Rubber) 23

APPENDIX A - Gasol ine An ti-Siphoning Pro tection ................... 23APPENDIX B Sta inless Steel Tanks 23APPENDIX e . Flex ible Bladder Tanks 23APPENDIX D Wide Tanks Reduce Stability-The GM Reduction .......... 24Specific Gravrty Of Common Liquida (Table) .... ......... 26Free Surface Effect and Loading Conditions ................ 28APPENDIX E The Common-Rail Manifold .............._....... 29Specify ing th e Cornmon Rail .................... 29ccmmcn-RanManifoids Have Many Appli cations 31AP PENDIX F Intemational P ipe Standards and Pipe-Size Tables ..... ._......... 32Stan dard Metric - U.S. Pipe COfTlparis on. ............. 32U.S. ISO Pipe Des ignations - "ON" Pipe Sizes 33U.S . P ipe Thread Standards ... ............... 33Hose-to-P ipe Sa e Consi derations .......................... 34U.S. IPS (NPS)P ipe-Size Tables 36Metric DIN 2448 Pipe -Size Tables 38

Appendix G Ap prox imale Feed and Retum line Diameter - Diesel............_.. 4nGaso line Fuel Line Size ................ ......... .... 40Appendix H Fuel-Filter Micron Rating {SieYe Fineness) 40

Fuel Systems For Boats - Course Number T I 581

Theother invaluable guide is me AmericanBoat & Yacht Counc (ABYC's) sections on fue! systems : H2gasoline) and H-33 (fer diese!) . Though ABYC's standardsa re guidelines onty. if YOUre building or repa irand ocn't comply fully with CFR yacht and as completely as practical wilh ABYC H-24 orH-33, you're leayourself open to serious probtems. including potent ial legal acncn.'Mlat 111 dohere-using t he aboye references asa s tarting point- is go through goOO practice in sound fusvstems. includ ing oeteuelike relum-oil coolers erepiping manifolds , which aren't specifically covered inrequ irements orABYC recommendations.Run ning PipeThepiping schematics show simple andreliable arrangements fortwin.engine inboard vesseis with twin tdiesel and gas. Ifthe boal has no generalor, just ami! the generator piping. tf the boat has lINogen seis . danotherbra nch for tha t. If the boat IS single-engine . eliminate the valves and piping for the one 8mrunabouts andday boats can be fit led with one fue! tank. Larger asOshould preferably be equippedwilhlINo It costsa bit more lo do this, and some Iess expensive cruisersha ve only onetan k, bUli!'s not goodV'itly? VWhdiesel. if !he klne tank springs a Ieakor becomescontaminaled youve had i1-o o more fuel. \tanks you can almost always manageto motor home . Even with gas-when you have lo shUldown if a tasprings a leak-y ou stilt have a secondchance if one tank becomes contaminated with dirt o r water.

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FuelSystcms Fo r 80a15 - Course Number TT 501Double Your Filters-Doub le Your FunThe only slightlyunu sualfealureof lheseschematics is lhe duplex fuel fill ers. Fueltanks and fuel supplies areseldomas e1ean as lhey oughl lobe. A bad batchof fuel or some sludge gelting inlo lhefuel linescan cIog a filterand stop an enginer ighl quick. Invariably. lhi s happens wilh a menacing squall bearing down, or during e1osequartersmaneuver ingi n harbor. The dup ex syslem shown permils swilching lo lhe second filler, remo . g,e1eaning and replacing lhe e10ggedfill er and continuingon wilhoul even slowing down. (Ona gas-engine craft youwouldn'l wanllo change lhe filter wilh lhe eng ine running, bul you can slill switcho ver and lhen e1ean or changelaler.) You can make up such a system trom over-the-counle r fill ers. valves and piping componenls, or--muchbetter-youcan purchase a ready-ma de dup lexs yslem trom companies like Racor andSeparo(A Separ duplexfiller is shown inthe pholo). Wilh a single-enginev essel, lheduplex filte rs and fuel lines need onlybe largeenough lo handle lhe one engine.

Fuel Systems For Boa ts - Course Numberthefilters should be aboullevel with the fuel pumpon the engine. The maximum lift (verticalh eght) fromoff altna tank to lhe inlet port enthe engineis 48 inches (122cm). Even lha t is a b it high. Less is alwaysLift heghls approaching o r over 48 inches (122cm) require insla llation ofa booster pump.VVheneverthe f il ler is aboye lhe tank level, a h and wob e-pump (or simlar) shou ld be inslal led in the feethal filter and lh e enlire feed line can b e p urged of air andfilled wilh a solid slug of fue!.Gas-Engine Pip ingThe schemalic showsa straightforward gas-engine fuel-piping arrangement for a twin gas-engine boat wlanks. In norm al operation, the port lank feeds lhe porte ngine and starboard lank lhe starboard engine. Tcross-over valve is closed . If you want, however, torun off , say, the starboardtankonly, then you shut oftake-off valves onlhe port lank andopen the cross-overvalve.

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Fuel Systems For Boats- CourseNumber T I 501You can add itionall y set up te have opt ional draw direct frcrn the wing tanks, the piping is stIaightforward , thoughinstalling a ptacerc of the piping schematic isst ill highl y recommended .For the senccs voyager, routinefi Uingot the day tank gives agood regular reck oning of fue l consumpton. Evenbe tter, you can install a te- between the main tank s andthe day tank as s hown. In out-of-the-way places-wherefue l quality is often very poor-th is gives you a chance to double filt er and to mon itor fuel quality asi t feeds theda y tank . (Th is pra ctice is call ed MoIishing" the fuel.) For t h is reason, I don ' ! l ike te fit the day tank with a deck fill ,though a venl -o f course--is still necessary. I prefer to pump !he day tank futl on ly from the main onboard tanks .With tms fue l po lishing , you can safe!y use dirtier fuel --i f y ou have to- than you'd be ab le to with a single passthro ugh a single filler . Vvhat's more, dirt a nd sludge have a second chance tes e ltJe out in the day tank. Obviously ,in such situations, all the filters have t obe checked, drained, and cJeaned very frequenUy.Bypass Feed UnesShould the fue! tIansfer pump fail , the s chematic shown includes bypass feed lines direct from !he wing tanks tothe eng ines. The bypass valves are normally cIosed--open edon ly inemergencies . Note that this emergencyconfiguration vioIates the always-take--and-retum -trom-the-sametankrule . There are no retum unes to t he wingtanks. If you, say , draw directly from the port tan k tofeed both engines then the retum fueI will be stiU be goi nginto the day tank . A t60 gallons per hour (227 IIhr) grossfuel flow, thefe wouIdbe roug hly 20 ga llons perhour (76IIhr) fuel consumed ane! the remaining4 0 gallons per hour (151 IIhr) spin back to the daytank. A 150-9alloo (568 1day tankwould be topped upthis way in 3 hours and 45 minutes. Accordingly-tn an emergency like this-thea-ew wou ld have to mon itor the day tank status and switchto drawoff it, rather than the wing tank, when the daytank neared full. Another altemat ive is to install two transfer punps in a switchable duplex arrangemenl In thiscaseooly a fuI! electricoutage would require use of the bypass fuel nes , as i t's highly unlikelyth at both transferpumps wou!d go do wnal t he s am e time.Fuel -Transfer Pum psThe fue l--transfer pump shouId be self-priming and have the f10w capadty lo f ia theday tank in a reasonable periodof time, say under 15 er20 minutes. In real-wor1d installations, pumpsseldomdeliver more than 70 percent oftheir rated f\ow. Thu s, for, say, an 80 galloo (3 03 1 d a y tank, youwant about an 8.gpm-rated (30 Vmin.) pump (80gal. + 0.70 = 114 ga l., and 114 ga l. ..;. 15 minutes = 7.6, say , 8 gpm - or , 303 1 ..;. 0.70 =433 1 an d 4 33 I ..;. 15minutes = 28.8 Umin ., say 30 Umin.). Rotary sliding.v ane pumps meet!he crtteria for self-priming-a t least withi n 2feet (60 cm) or so of Iift, adequate for most boa ts-a nd they're avai lable rated for con tinuous u s ewith diese! fuel.TOOugh se ldom c ri tical, It"s worth consider ing a reversible vane pump, which wi l lenable you to empty the day tankback into one of the main tanks, for c1eaningo r repair. Gear pumps are another good opt ion , pa rticu larl y fo r largervesselsre quirng high transfer rates.High .vo lume transfer pumps c an generate high pressures should a blockage occur. In the WQrst case , this canl ead toa fuelline rup lure and a horrendous fuel spill. Such pumpsshould beprotected with a relief valve . Sinceyou can't have th e rel ief blow-by spraying in t o t he boat, t he blowbys hou ld be plumbedthrough a bypass l ine intothe nea rest tank , usuaf ly the day tank. An alarm a nd a n a utoma tic pump shut-off on the relief valve complete thesafe ty piclure .If the Cfew mon ito rs l he fuel t Ia nsfer carefully, the y can shut o ff thefuel transfer before overfi lling . It is, however,to easy to forget. I recommend a second tank-level sensor be instal1ed in the day tank , and ded icated tot r ansferpump shut-off. It should be set up to automatically switch off !he transfer pump al abou l 97% full. A one-timeaud ible alarm (a few beeps, a momentary rng) alert the Cfew.Note that the fue!-Iransfer pump must also deliver fuel at a faster rate thanmaximum fuel consu mption. Fordieseis this is t he actual fue! con sumed, and--f"egard less of ma nufacturer da ims- it's almos l always c10se to0 .054 gallons pe r horsepower per hour, or 0.274 l i tersper kilowatl per hour, Fer twin 35D-hp (261k w ) engines(700.hp - 52 2 k w total ) this is 700 hp x 0 .054 gal.lhp/IY or37.8 gph. Dividing by 60 gives 0.63 gpm . Or , 522 kw x0_27 4111


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Approximale Full Tan k Weights - Pounds lInc luding theTank rtself lUS Gallons Dtesel Gasoline Waler20 156 135 18040 315 272 36260 470 405 54180 621 535 716100 797 690 916120 953 825 1.096150 1,183 1,022 1,361200 1.575 1,361 1,813250 1.956 1,688 2,253300 2.335 2,014 2,692350 2,778 2,403 3,194400 3.279 2.851 3,755450 3.671 3,189 4,206500 4.143 3.608 4,738600 5.024 4,382 5.738700 6.017 5,268 6.850800 6,826 5,970 7,778

A1uminum-Strap Ho ld DownsPerhaps the simplest, Ieasl expensive, and most common tank hold-downs are made from aluminum f1atinch (3 mm) thid N C08s t 6 , rd Cf1 St Gu rd vent OIItlr/){),rtIA / FIJeI HO e JO WJrtls/ JII.A} FIJeI HoS# 8u :kfm< Mes"To FII(ff ' SJ (,,4St 6v , r t IA l FIJeI Ofe",, r op of r l nK, S I ~ F ( ) , ', ' Or"n".Al u ," rie-Oc_ , 'Srr,p , ', , . ;:= - ! : :: - . ;""" " / ' 10 2 1 1 ~ t " " e U lu " b u c ~ t ! " f ' M fflI lI ffY, , I I rn t ' /8r .0/I, , ;',m1 t1, , '

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Fuel -Lin e ValvesCFR yaeht, CFR commercial, and ee ABYC are strangely silent onspecifie recommended valve types for Iuel systems. Technically, any typeofva l ve is acceptable that will withstand the requ ired 2-112 minute bumtest, and that has packi ng which won't break down on contad with thefuel . Forexample, sorne Detroit Diesel manuals recommend tne use ofgate vefves fortheir Iack of restrictionen fue r fIow. In fact, gale vefves. andanyvalves with packing, are pctenertroctae. Even ifthe packing ccesn'tbreak down from thefuel, i twi ll wear out eventually. Accordingly , novaives wrth pading b Iheir primary seet shouldbe used in fue! piping.

Fuel Systems For Boa ts - Course Number TT 501

The twobest alternatives are globe valves and qua rter-tum baUvefves .Globe valves are accepteoe . but causerestriction in fuel flow due to theirconstruction.A1so, you cao't tel ifthey're cpen Of closed simpty byglancing et them. Two arguments in favor of gloOO valves are that theyscrew up ere down so they can't vtbrate open or dosed accidentally, arethey penn it adjustment for partal f\ow. Partial f\ow, however , isn 'trequ ired for fuel shutofts . In my opinton, quarter-tum ball vafves are tbehands-down best choice. They create no reslriction in the fuel f\owFurther, thepositionof their hanclle gives instant indication of whetherthey're ooen orcsosec . An added benefit-ball valves are l ightandcompact.Cheaptyrnade ball vaiveeneve been known to vibralethemsetves ccen Ofdosed bu! well madeones don 't engage in suchhijinks.Of course youmust make cert ain that Ihe fuel-Iine diameter and vefve size meets your engine manufacturer'srequiremenls--the inlel port see onthe engine. Ifthe fuel-suppty run is very long or has numerous bends andfittings, t's a good idea to90 upone size lo reduce friction (See arso Appendix G, page 38)Remote Fuel ShutoffsNeither ABYC (1()( CFR yacht requireremote fue l shut-off valves outside theengi ne compartment. CFR commercia rdoes . Frankly, I think remote fuel shutoffsshou ld be requireden all boats over28feet (8.5 m)with inboard engines andcabin accommodations . The reason isbolh simple and frightening. The bumingboat pid ured in lhebeginni ng had all therequired fuel shut-off va lves on the tanks.It also had fire ext inguishers on board . Adiesel Jire like this is l ike a bl ow-torchhowever, Cracking Ihe enginehatches,Ihe f1ameswere so intenseIhatthe Jireextinguishers were about as effectiveasspitting int o a fumace, If lheerew couldhave got down and into Ihe enginecompartment lo reach the shut-off valvesfirst thoug h, they mightwel l havestopped oralleast slowed!he fire. Inreality, it was too ho l to even thinkofgetl ing cJose to the halch. Enlering theengine compartment wourd have beencertain death . Forthis reason , I specifyremote fuel shut-offs on all my boals.These are simple Iinkages (1iketh rottlecontrors or push--pu tt cables) that allowyou to tum off !he fue! r ightat the tankwrthout going near!he enginecompartment---cheapinsurance.

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Fue) Systems For Boa ts - Ccurse Number TT 501 Fue ) Systems For Boats- Course Number

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KingFSher - 66- Foo t Expres s Cruisc r I Sport sfOW1. 5 7 It . - 3 in . - Beam : 19 . O in . - Dra: 5 nGerr Marine, Inc .838 wes r End Ave.. Suite BB New York. NY 1002 5're. 21 2864 -7030 - Fax : 2 12-9320872,

Fuel tanks located over the LeS , with the center01 volume nearthe water line, on a planing hulL

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For sornereason, I see this approacha pplied lo voyaging motorcruisers , which are somelimes designedhugefuel tanks bui lt intodouble bo lloms. This is peor practice . If t he sucha vessel is adequale ly stiff wittanks, l henadd ing 6 tons or more 01fue! this Iow downwould make he r la r too st i f f -dangerously anduncomlortabl y so. eon versely , if Ihe boal relied en the weight 01th e l ue!on the double bo llom for properthen she wou ld be dangerously lender when empty . The proper verticallocation l ar b ig tanks on long rancrui sers is lairty high, with the tank's center al voIume al or even jusi aboye the DIM....P1anng hulls ad ually can benefil l rom tanks somewhat aft of the center0 1buoyancy. The goal is lo havevessel mm leve! when lighl, and a bit down by t he stem when heavy. Again, tanksshould oot be too \Qw .hu ll fo rms alreadyhave quick snappy roUs. The vertical center of the tanks are , aga in . ideally a lor a bil awalerline. The drawing shows a 66-loot (20 m) express cruiser of my design that has the tanks Ioca led ri

The optimum Iocal ion l ar lu el la nks is over the boat's center ot buoyancy. Th is way the re is no change invary ing tank levels. and the wei ght is kepl outo f the ends to red uce pitching_On sailboats , it is also impoIocale tanks as low as possible lo maximize sail carryi ng powe r whenlopped up.

gal loo (0.85 1 kg per titer), and gasoline 6.06 pounds per gal lon (0 .73 kg per liler).A Iong -range motoryec2,000 gallons (7570 1 ot diesel l uel wil l vary 6.3 100s between tul! and empty! A la r ge high-speed twin-d lecurse - mght well car ry 1,200 gal lons(45401)to gel adequale range--3 .8 tons' [lb .lgaL x 0,1198 =kgll ]

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Fuel Systems For Boa ts - Coursc Number T I 501 Fue)Systems For Boats - Course Number

Wall Th ick ness0 .032 in.0 _035 in.0 .042 in.

Tub ing Outside Diam et er118 in . to 1/4 in ,5116 in . lo 318in.7/16 in . lo 112in .

A2 Fue l FilIHoseOesigned for applications where fuel is not normal ly i n t he l ineand wil h a re-resrstant cover.8 2 Fue l FiII HoseOesignedfar applicalions whe re fue l is not normally in !he une and wilhout a re-resrstent cover .Unfortuna le!y, A1 hose is not generally availab le in sizes large enough for fuel fi lls. In this case . use A2 fiHolding HoseSince you don' want l hese beses com ing loase , make sure Ihere are marine-g rade stain less steet hose ceach connecnoo. and thatIhere are proper barbed hose connectors et each hose joinl or at tachment. Nathe hoses have to be supported with corrosion-res islant, chafe -fre e cupe orhangers . Pay special ettenttowherever hoses pass through a bulkhead or panel. A roughedge here is certain lo wear through the tougmalerialsoo ner or leter. Protect Ihe hose wil h soft r ing grommets instal led in me hote

Hose Outs ide DiameterClamp Wi dth7/16 in. and under 1/4 in.7/16 in. lo 13/16 in 5116 in.13116 in . and ove- 318 in.

Recommended pra ctice is tha t t he hos eextend one nose-ciemc width (o r a bit more) beyond !he hose claTh is enseres solid l eak-free attachment.

CFR yach l and ASYC requ ire double 112inch-wide (12.7 mm wid e) damps on alllarge-diamele r fue r ro sas fill pipes, though these may fasten lo smooth pipes without hoseba rbs . A11hose d amps should be of 1percenl 316 stainless

Older vessels used soft copper tubing wi lh sla ndard fiareconnectors for almost allfue lline and venl pipinis sti ll acceplable according lo CFR yacht and CFR commercial pmv ided that a ring-spiral loop is built inlocopper tubing before each rigid component l o absorb f lex. These metalspirals , however , can work. hardecrack over l ime _AccOl"dingly , A1 fue l-line hose is grea lly preferable. Hose i s also cheaper and eas ier to pand inslall. Copper , copper nickel. nickel copper. a nd stainless stee l are Iheapproved fuelpiping metals.Minimum wal l Ihicknesses for tub ing shouldbe as follows:

American Soa l & Yacht Counci l recommended fue l-hose c lamp widths are as onows:

Hos e Ouf3ide D iameterClamp Width11 rrvn and under 6.3 mm11 mm lo 20_5 mm 8 mm20.5 mm and ove- 9.5 mm

82 Fue l Ven t HoseDesigned for applicalions whe re fue l is not normally in ee line and wrthout a re-resa tant cover. lntendedendosed eng ine spaces.

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~ M o o n A v o,..., l" , MotoryKbtLOA.:82 ft . 3 Lo D."1. 72 ft . - 11 iD .Beam , 17 n. . o In. Draft, 7 ft. - 6 .in..

'ranks aft 01Le S on a o.soracement voyager. center of tank voiume nearwa ler line Seawatertrim banas! tanks a. also with center 01voiume near I he water une.

the LCS , and al the idealheight. In this case ,wewere able lo make th e tanks do double duty in b10cking sorneengine ooise from the accommodations.

Though the ideal is l o nave targe tanks over the LCS. Real-worId considera tions can make Ihis impractical. Th iscreates mm problemstnat musl be add ressed. One solut ioni s multiple tanks and pumped dislribution of fuel tomaintain trim . For long range voyagers, a better opten is seewater trim ballasl taoks . The drawing shows an 82tcoter (25 m) we designed , lhal has the 5,840 ga llons (22106 1)of tankage as re ermidship as was possible, andwil h the tank 's vertical cenlers almosl exacUy al !he VYL.. Still, these tanks are aft eree LCS _The boat is designedto t rim leve! with!he tanks al 80% capacity . She's downa jusi bit by !he slem al 100%. As the tanks empty below75%, the aft seawater ba llast tank is pumped up lo compensale and maintain rever trimFlex Con nectorsVlbration causes lhe hull , piping . and machine ryto W()f1( constanUy. For Ihis reason. connections lo the firmlymounted tan ks and allotn er comoooents ofthe fue! system is besl made with flexible hose. Yoo can get awaywil h rigid pipe connections lo Ihe tanks. if that's for sornerea son necessary , but yoo absolute ly must use aflexible tubi ng or hose be tween the piping and the engine Of gen set. Fail lo do Ihis and yoo 're certain to gelcracks-major trouble! Good fuel-hne hos e rsn't al1 lhat expens ive ; il doesn't makesense to scrimp_In someinstanc es other g rades--like A2 Of SI hose-a re permissible , bu l ideal1yyou should use all Coasl Guard A1-gradefue l-fine hose . Th i shose meets SAE J1527 (ISO 7840) specificationsfor hose conlinuously fiJled with fuel, and wi llw ithstand a 2-112minu te burn lest I'd rep la ce anything else. Such hose is clea r ly labeled "A1" oo tside, there 's nomistaking i t.)

A lum inum Fue l Pip ingSchedule40 (standard) marine aluminum pipe can be used ford iesel, but CFR commercialrequires sche(double weight) for all al uminumfue!piping , and this tSa llowed on aluminum vesselson ty. For yachts of amaterial, youc an go wi th atuminum. I recommencl you stick wilh the schedule 80 requiremenl however . C

SAE J 1527( ISO 7840) Marine Fuel Hose TypesA1 Fuel Feed HoseOes igned for having fue l in !he hose al l !he time and with a flre-resistanl cover .A2 Fuel Vent HoseDesigned for applications with fuel nol norma lly in !he lioc and with fire-resistanl caver .81 Fuel Feed HoseOes igned far having fuel in the hose all !he time but without a fire-resislanl caver. Inlended for non-endosedengine spaces .

Tub ing Outside Di ameter3_2 mm lo 6 .3 mm8mm t0 9.5 mm11 rrm lo 12.7 mm

WaJl Th icknes s0 _81 mm0 _89 mm1.06 mm

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.._"....-. _0_.. ...... ~ . - - - _-Westla,,'o lostitute

Unlortunately, it 's hard lo find off-Ihe-shell venl littings l arger Ihan 518-inch (18 mm) diamele r. One solutioins tall a 314inch N.P.T. (DN 20 mm) pipe fitting in Ihe tank (0 .82- in. - 20 .8 mm I.D .)wi lh a ..,.. l ee fol'kintwo standard SI8- inch (ON 18 mm) vents.On large or long tanks, you wo uld install one 01these al each erunning to S /8inch (ON 18 mm ) ven l f il t ings-Iour venls fitlings lo lal lo r each tankCFR commerciar has a numbe r of vent-size variables, but basically requires a minim um venl cro ss-sed iequal te 314-inch(D N 20 mm ) 0 .0 . tube with 0.035-inch wall (20 gauge 0.889 mm). This is 0.36 sq.in. (sq .mm) The 3/4 -inch N.P.T_( DN 2 0 mm) pipe fittingV ed te two 5J8-inch (DN 18 mm) venl fittings meels trequiremenl.Vent-Run ConsiderationsFue! tanks must never .ever vent inlo !he hui ; theymusl vent overboard as shown. Any other arrangemendl.mp vapors and spill 1010 !he bilge -a sure harbinger 01a real blasl ! T o keep water out, Ihe v en l shouldhigh as poss ible and equipped with!he 4-VK:h(100 mm) or highe r gooseneck orr i ser shown. Venl openinat least 15 inches(38 cm ) away from any opening inlo!he huI!. Fuel+ank vents al so requ ire a baddire f1awith 30 wires per ineh (1.18 wir es per mm), eaeh way . This pre vents flame f rom spreading down inlo lhepipe, which seems prudent lo me. CF R yacht and ABYC require that!hemesh be "cleanable.-l n prad ice , Ih is means that Ihe mesh or t he vent un itwith Ihe mesh has to be removable. Presumably, if you can remo ve il youca n c1ean il

ABYC requi res thal Ihe vent l ine shou ld be al least 25percent 01the cross-secuoo erea olthe f il l pipe, Fostandard t- t za-mcn (ON 32 mm ) 10 . ns, this calls for a msnmem 9116-inch (15 mm) earreter hose (to m7/16-ineh (DN 11) d iameler vent fitting) . This is an erea that I Ihink could use some revision . Modem fuepump al sueh.a tremendous rale that these small vente are often iacequate. Further- lhough lhey are fcon figured In Jusith is way-the vent openlng on the tank shouldn'l be neer me fil!. Instead . it should be aopposite end o, Ihe tank. On ene 01my designs, a relatively long narrow tan k wa s tted with Ihe standardrr inimum vent anO' fill sizes specified above . and wit h Ihe venl near lhe fil !. The resull wa s t h a l ~ e lhocou ld lee! air whooshing out 01!he vent-the pressure sensor on Ihe fin nozzlewould shut i t off regularlymoment later a Iarge bubble 01air would bursl out Ihe Iin pipe,spewing fue r over!he deck . Installing a secnear the fill helped, bu! endn't fully elimlnate !he pmblem. Addlng a vent at Ihe tank end away from Ihe f il lCU"' .

Vent-a-TankTank vente anow air lo exit the tank so you can add Iiquid (which is ou r goa l, after an). Vents (termed ' brein Europe) arsc pro lect aga insl devetoping excessve pressure in !he tank . It is best lo recommend not totanks 100%. On a hot summer da y !he lemperature in !he unde rground storage tank can be 65- F (18- Cwhereas the temperature in !he engine compartmenl ma y be over 100- F (38 - C) . II the tank is lopped upcoolfuel , the fuel can he a t u p a nd expand enough lo spill two O( three gal lons( 7 to 10 1 overboard Ihrouvent. Yes , anc ther IlIegal o spill.

FuelSystems For 80a15 - Course Numbermuch more practical.

Vents Under PressureLarge vessels may be fueled under pressure ralher than lrom a simp le fue lpum p nozzle. Th is places sti1l higherdemandson Ihe vent lines. Clearly , ifIhe venl lines we re t oo small , inlema l l ank pressure cou ld bui ld lo burstingp? ln t. For lanks filled under pressure , Ihe v ent linesmust be Ihe samedlam eteras the finpipe or rarger. My practiceha s bee n to instal!Ih e two

It"s bes l practi ce that eaeh tank have i t's own ded icaled venl line. AIl ve ntsmust essential ly nse oontinuously from the tank. There can be no sag s ordl ps in an y vent line te ho ld fluid or debris. If unavoidable , very shorthorizontal runs (no more than 18 inches - 450 mm ) are acceptable , but suchhorizontal runs increase !he c:hance 01a potential c Iog in !he venl line . Aslong as the vent run rises continuousiy you can combine vents from differenttanks inlo one line. You ca n do this only if Ihe tota l cross-sectional area afterpn ing is equal lo morethan the combined cross-sectiona l area 01Iheindividual lines. Such Iarge diameter venl l ines won 'l fit off-Ihe-shelf ventfittings

-14 -

:, ::: -r-;1 1/ 2 Ul "'11 p ,!,#1" " 1 e.p:&AS Dr DIESEL

,"o,sr6IJNdAl : H o

c""sr 6turilA2 H o $ ~l ! j " - ~ Dt:J.JtU 55

HDU C iIfl'Ps

Note that on commercial cra Ihe Coa st Gua rd is now somebmes requinng the next step up even from A1 hoseshielded hose. such as AeroquipFC 234 . This meets SAE J 1942 (Ioonerly USCG COM DTINST M16752.2) typeA hose f ire test entena. My personalo pinion is tttat this IS cverou. lt's cheaper just lo comply than lo arque thepcmt . Remember that even ifIhis hos e is much moreexpensive tha n A 1, you onlyneed a shorl lengths 01 it f romthe rigid piping to Ihe engineor generator.

WestIawD l nstitu te

Of course. all rigid lu bing orpipe mus tbe well supported alregu lar lntervets . The re muslbe a support nomore than 4inches (100 mm) from eithefend . where it connects loflexible lineoAIIhough COppeflub ing spirals shouldn l beused lo connect betweencomponenls , there's nodrawback lo using rigid tube orpipe (01approved materalsand type) la r long fue l runs - ifthis is convenient - as long asflex ible hose makestheconnections at the engi neand---bener s t i l ~ a l either end01 the rigid pipe

comme:ial does nol ancw hose for fuel piping , and inssstson en solid pipe or tube, except lor a short length 01hose al the eng ine or gen set. Though I loIlow the rules (there is no cho ice ) rorcommercial cre, this ene coesn'tmak es ense 10 me lor mos t yachts .

Fue! Systems For 80a15 - Course Numbe r T I SOl

Eliminating Sparb5pal'ks are alwaysa potential problem around gasoline. In order lo prevent static build-tJp, you musl lit jumperground wires across al l the gaps between fill and tankcreated by Ihe hose connections. The jumpers musl benumber 1()..gauge O( larger wire, ane!s hould be either soIdered te anO' under dedi cated hose c1amps las tenedaround Ihe pipes , O( lastened l o !he hose clamp wilh a ded icated ring tenni nal andscrew-no l Ihe double d ampsaround th e h ose itself . (Yes , !'ve ad ually see n Ih is; you've gol l o wonder!) The tanks themse lves-ff meta l should also begrounded with number-8-gaug e wire or larger connecled lo Ihe baat's bonding system.Even though diesel won 't ignite Irom stalic spark, d iesel tanks and piping should begrounded as wel l to controlcorrosian . Many small l o mid-sized FRP and wooddiesel vessels are nol equipped wilh a bond ing syslem.Pertlaps Ihe best soMi on lor such crafl is lo bond ! he lanks and fU pipes alone to an independenl through -boltedexternalzinc . You have to tak e speciaf care not l o accidentally cross oonned lo any pa rt olthe electrical syslem .Tank Ope nings and Penetrat ionsOn ga soline tanks, all openings or penetrations (vents. Iills, take-ofts, Ievel gauges, c1ean-outs) must be en the topof the tank-n o exceptions . [)tesel may have openingsand penetrations en the tank sietes. encIs, O( lops , but it 'sbes t lo pul mast open ings on Ihe t op to minimize c:hances 01leaks. The exception s are large dean-out manholes_Such c J e a n ~ are highlyre


11/24

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12/24

- - - - - - - - - - - - - - - - - - - - - --Fue I Systems Fo r Boats - Course Number T I 501 Fuel Systems For Boats - Course Number

- :!.7 n e wI Jb-=--

[l] STOLl. HUBERT e S T SYSTEMS , o lOl 3MDESIGN tliG " A OR C1TY,UstR IAI .. :;

DATE O W Ii _ l /Q !.. f UEl TY?i _ , : : . : .C A P A ' ~ : Q 'l r: .1 1 lo . VA'P:t " HJ2 . 19

'C.JTank Labelsl ocating a tank 's manufacturer shouk:ln't bedif fCUlt _The CF R and ABYC recuse thatalltanks be labeled with the manufacturer's nameand addressas wettas date of manufacture ;intended fuer type; capac ity; tank material andthickness; serial number ; and maximumtestpeesscre.Tanks Un der PressureSeveral years back , I had a Iaunching delayedbytwo weeks . The vesser seemed read y in anrespecte. when me builder nec me tank only lof in d a steadyleak-naturally on !he tank'sbottom . The on ly out was to remove the soft patch. (Hap pi ly-i f it ca n b e called Ihal- I'd inset ed one bewe 'd neve had to cnemsew t he deck .) Then, we puuec tne tank and retumed it to the fabricalor. Now, lhamaker da imedh e'd run a pressure les t , but sornehow 1doubt .

VIIhen you're installing a new ta nk, it pays lo perform the sim pl e m inimum pressure test required byIh e Cno!. difficult . A shop alr compressor, standard hose fittings, and pre ssure gaugewin do !hejoboM ernatelya vertical "slandpipe" to the fin opening (a watertight screwin frt). Sear tight all other openi ng in the tank atank and pipe wilh water t o t he top of Ihe standpipe. A pipe 7 fee t (2133 mm) high g ives 3 psi (20.7 KPa)fee!, 6 inches (3505 mm ) gives 5 psi (34.5 KPa) of hydrostat ic head . Leave everything to sil for sixhourstank shouldn"t leak a drop anywhere. If my builder haddo ne th is before inslaJiation he 'd have saved himsof work laler on.

Tank Pressure Ral ingsABYC and CFR yaeht bolh req uire that all fue l tanks in pleasure cra fl be able to wi thstand 3 psi (20.7 KPpressure. Thls jg substantlally Iessthan the CFR commeroal req uirement of 5 psi (34 .5 KPa) . ABYC andy e h however , al so require addilionar tests suc has s losh lests and pressure-imput se lests. These are npra ctical for any bU! large commeroal tank fabncators . Accord ing ly , on my custom des igns, I atways spethe tanks be bu i ll lo 5-psi (34 .5 KPa) commercial or T-boal standards . This isthe mos t cost-efJective wayc10se lo ensunng that a custom or short-run production tan k wou ld meel Ihe additiona l slosh and pressurtesis . Be carefu l in tesbng tanks; however. If you tesl a 3 psi (20 .7 KPa) tank to 5 psi (34.5 KPa), you mabursl it ! Check !he tank label before runn ing any pres sure test, and if in dou bt test only to 3 psi (20 .7 KPatank on any boa t shouk:lbe accepted if it can 't w i thstand th is pres sure.

Thi s construction is tenned lapped-eomer construdion (someti mes f1anged-eomer con slruction) and-lhsupenorf Of rre tat tanks of smaU to meccm sue (it can't be used on plate OVe!" 3/16 inch, 4.7 mm thick.the lhick plateewont' take the bend). it ts nct acceptable under t he CFR for commerclet vessets . The reathis ts nol clear. I Imay ste m f romth e incorrect practice of fab ricating with lapped external comers that cowater (partlCularlyon the top of the tank) leading toc orr osion . Regard1ess. tms is the regulation. and lapcomer cons trucbon cannot be usedon Coast-Guardinspected vessels-passenger vessels.

On larger vessel s built to 5 psi (34 .5 KPa) , an ll -foot, G-inch (3505 mm ) standpipe might not be tall enoudesignp ressure shouk:l be 1.5 times !he pressurefrom !he deepest drop from the highest vent opening_A(366 cm) vent height, would can for a 12f t_x 0 .43 psiIfl x 1.5 =7.74 psi , or 3.66 m x 9.7 KPalm x 1.5 =5pressure . (One toot of standpipeheight equals 0.43 psi of tank pressure-fresh wat er. One meter stand phelght eq uals 9.7 KPa of tank pressure-f resh water .)Level Gaug ingIn the "good '01 da ys: you'd check tank level by sliding a so unding stick down the fin pipe or down a dedicsoundiog pipe. 'Ni thdrawing the sounding stickyou 'd read the level (Iike a car Dil dipstick), thoughIh is isndo al nlQh in a storm, These days , il 's not unusual for t ank s lo be loca led where a direct f ill run for a sounlS Il1lpossible_StJII- ff it 'J f it-the sound ing stick is the bulletproof backup Jormoc:Iem tank gauges . It is, hoU"ICOI1veNenl for regu lar use . For obvious rea sons , Ihough, you 're reqUlred lo ha ve a leve!ind icator . andastandard tank gauges wiUwork if property installed. (The sounding stidc a1one rneets lega l requ irements.)plas tic-tube slQht gaugesare too eas ily b r o k e cau se a majar splll. 1don 't recommend Ihese in pprop er manne tank level indicator syslem. Such slQhl gaug es are illegal for gaso hne in any case_

,1 11.

El

Ba'fles;n an lI"legralia1ummu"" tank Note lile ' e"l ocifcul areut-outsare-ce"ltereC>


13/24

0.09000.10000.12500.19000.2500

2.292.543.174.836.35

1 - 300190 - 300300 - 560560 - 11001100-1900

Fuel System s Fo r Boats - Course Number

Alumlnumta nxs po,nletl outsidewith whl!(:epoxy pamt. oteo Ih", hOlseyesanc nernerous take-o relum. fill. and sender fttings .

1 - 8050 - 8080 - 150150-300300-500

Alloy: 5052,5053 ,o r 5086

Westlawn Institute

Aluminum

CFR commercial requiresthat metal diesel tanksbe made only of nickel-copper,steel or iron, aluminumtiberglass. Stainlessi s not accepted. Further, it insists that all aluminumt anks-e ven tanks of just 1 or 2(3 or 4 l iters) be a minimum 1/4-inch (6.35 mm) thick. This is considerableoverkillf or such smalltanks,opinion; however, you're buildinga crewed-charter or passenger vessel you mustcomply.

Note the thicknessesaboye occasionally need to be increased to achieve proper structura l strength.

Fiberglass Tank ConstructionFRP tanks havet o belaid up over a male mold, so the inside surface is smooth and tinished. AII corne rshould be 1-inch(25 mm) or larger, and the inside 50 percent ofthe laminate should be all mat, slightly

Tanks Can't Be Used As Str uctureExcept for integraltanks, tankscannotbeused as part of the structure . Youcannotmount machineryon or to tanks.

Glass Tan ks & Integra l Tanks (See Important Update, Page 22a)Interestingly, tiberglass tanksa re not only acceptable but superior for both gasoline and diesel. FRP tansome greatadvantages: They don't corrode; they don't conduct electricity; they weighless than metal tatheycan bemoldedto t it the hull moreclosely thanany butthe most expensive metaltanks, yield ing grecapacity. Bertram and Hatteras are just two of the qualitybuilderswho install UL-approved tiberglass taThough theCFR yacht and commercial rules permit integral tiberglass diesel tanks (molded into and aghull itself), they aren't allowed for gas. Steel and aluminum diesel craft, also, can have integral metal tanthe commercial CFR; however, wood hulls cannot. (You can have integral wood-epoxy diesel tanks on yIntegral tanks provide the maximum fuel capacity atthe lowest cost and volume. They're very slightly mto leak, though. This is the reason,integral tankscan't be used on gas-engine craft. Cored FRP hulls (ucommercial CFR) can also have integral tanks for diesel but(if cored) only PVC foam is acceptable in thany of the tank walls because there's been occasional trouble with sounding sticks penetrating the innercausing the most interesting leaks. Regardless, care is required to ensure that leaks can't penetrate intoIn addition-i f sounding sticks are used-there must be a strike plate directly under thesounding hole oinside the tank to prevent damaging the inner skin. Pleasure craft can and do use balsacore in FRP tantt's been found that ordinary orthopolyester resinw ill meet the 2 1/2-minute burntest requirement. 1recothough, that allt iberglasst anksbe laid up with tire-retardant isopolyester resin to Milspec MiI-R-21607.have slightly higher mechanical properties, greater resistance to blisteng,and higher resistance to cheattack than orthos. Fire-retardanceseems sensible prudence for fuel tanks. Isos are moreexpensive thresins but on comparatively small components Iike tanks, thecost difference is negligible.

A luminumTank PreservationMarine aluminum tanks are probably themost common. They're relativelyinexpensive to fabricate into customshapes, and are robust and fairly light.They have just one serious drawbacktheycan corrode. If aluminum tanks havebeen installed with proper ventilationallaround; with sloped or rounded tops todrain water ; with Neoprene padding,they'lIl ast a long time. For really longl ife,however, aluminum tanks should bepainted (on the outside on/y) wi tha goodepoxy-based paint system -a prime coatplus at least two tinishcoats (3 or 4 s better still). An aluminum tank built andinstalled like this willlast a

- 20-

Fuel Systems For Boats - Course Number TT 501FloScanIn addition to level gauges, 1like to ins ta ll a FloScan fuel-f1ow meters to provide the crewwith accurate real-timeinformati on on fuel consumption. On twin-engine vessels-w here possible - I prefer to install a single FloScansender in the lines feeding and returning from both engines but separate fromt he line feeding the gene rator(s).This way, it's easy to get engine mile-per-gallon numbers. The generatorconsumption can beestimatedadequatelyan d added, or a separate FloScancan be installed on the generator feed and return lines. Besure toinstall a FloScan meter that reads in the range of flow rate of yourengine (orengines). Multiply total horsepowerby 0.054 for gph or multiply kilowatts by 0.274 for liters perhour. Twin 350-hp (261 kw) engines-mon i tored byasingle FloScan-would burn about 37.8 gallons perhour (143 Ihr) combined, at max.

Except for integral tanks , nopar tof any fuel tank maybe used for structural support orhull reinforcement.

Westlawn lnstitute

Tank MaterialsThe tablebelow gives a list of proper tank materialsandthickness for nonintegral tanks with baffles spaced nomorethan30 inches (76 cm). Tinned copperw as the old standardf or gasoline, but as the tanks aged the tinreacted with the gas, creating a gumthatfouled the carburetor. (Thereare fewer carburetor engines around everyday, but I imaginethe effect would be evenworse on injectors.) Similarly, diesel tanks must never be galvanizedinside. The galvanizing zinc reactswit h the fuel oil, ruining thediesel. Copper also reacts with the sulfur in dieseland can be eatenaway. Plain old-fashioned marine aluminum, iron, or steel is the answer (monel is the ultimate) ;however, iron and steel aren't acceptable for gasunless hot-dipped galvanized insideand out. Temneplate steel(sheet irono r steel coated with an alloy of about 4 parts lead to 1 partt in) wa s- a l ong time ago- a commoninexpensive tank material. lt isn't acceptable for anyfuel tank, however. You'lI often come across references to"black iron" tanks. I don't know where this term came from. "Blackiron" tanks are simplyordinarymild steel.Stainless steelt anks must be of only316L or 317L ("L" for low carbon), and welded with the TIG process, perABYC. An even better alloy (not ABYC approved) is 321 stainless (see Appendix B). ABYC has now approvedstainless steel for diesel , NOT for gasoline fuel tanks. The one exception is thatABYC does permit stainlessgasoline tanks if they are less than 20gallons (751, are of cylindrical construction, and have domed ends. lpersonally can't see any reason to use such small stainless gas tanks. Polyethylene tanks are available in manyshapes in thissizerange and are much superiorfor this application.

FuelTank aterials & ThicknessesCapacity Capacity Thick Thickaterial Specificat ion Gallons liters Millimeters Inches GaugeNickel-Copper ASTM-B127 1 - 30 1 - 112 0.78 0.0310 22 US std.Class A 30 - 80 112 - 300 0.94 0.0370 20 US std.80 - 200 300 - 750 1.27 0.0500 18 US std.200 - 400 750 - 1500 1.57 0.0620 16 IS std.

Copper-Ni ckel ASTM-B122 1 - SO 1 - 300 1.14 0.0450 17 AWG200 - 400 750 - 1500 1.83 0.0720 13 AWGCopper ASTM-B152 1 - SO 1 - 300 1.45 0.0570 15AWGType E.T.P. 80 - 150 300 - 560 2.03 OOSOO 12 AWG

Copper-Silicon ASTM-B97 1 - 80 1 - 300 1.27 0.0500 16 AWGTypeAB&G 80 - 200 300 - 750 1.62 0.0640 14 AWG200 - 400 750 - 1500Sheet Steel ASTM-A93 1 - 80 1 - 300 1.89 0.0747 14 Mfrs.Stainles Steel 80 - 200 300 -7 50 2.66 0.1046 12 Mfrs.Aluminized Steel ASTM-463 1 - 80 1 - 300 2.00 0.0785 14 Mfrs.80 - 200 300 -7 50 2.66 0.1046 12 Mfrs .


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Fuel Systems For Boats - Course NumberTT 501 Fuel Systems For Boats - Coursc Numbe

Fiberglass Tank Wall Thicknesses(A11Mat on tne Inner 50 percent o f t he la yup , men Altemating la yers ofWov en Rov ing and Chopped Strand Mal,in Isopolyester Resm. with the Outer masl l ayer of Woven Roving)

te eliminate any pinholes Gelcoat shouldn 'l be useden lhe insidesuace, but a hea vy layer ct resin2 0 to30milis (0 .020 to 0.030 inches - 0.5 to 0.75 mm) thick. is necessary, again , lo eliminate any chance of pin hales.(Though rc t requ ired , the best interior finish employs 20 to 30 milis (0 .5 to 0 .75 mm ) of vinytester resin, which hasstill higher rese terce to chema l ettecs.) Outside ot the interior mat Iayup ahematlng rayers of woven rovingandma t are built u p to meetIhe thick.ness caneo far en the table . Since FRP is bendy, the usual pracuce to use aba lsa or PVC oore en the outs ideof the inte rior mat laminale (on ly PVC is acceplable for oommercial craft)finishing off the remaining mat-roving layupov er that.

Notes: A1 l lanks to have baffles spacedno more than 30 inches(76 cm ) bo!h athwartships and fore-n-aft.Tanks uncler 20 ga1lons (75 1)don'l need core for stiffness . Hatf--inchcore is good for tanks up to 120ga llons (4541, or SO, whi le, 3/4-inch (19 mm) should be used over 120 gallons (454 1. la rge la nks . over 400 gallons (1500 1)need to be carefu lly engineered, with baffle spa cing , sliffeners (if required), coreIhickness, and laminate allcalculated. 'Mleref ittings penetrate the tank, lhe laminale (sans core) should be increased 150percent in!hickness far about twic e t he d iameler or footprint of Ihe fitting.One excellent methocl of attaching fittingsrecommended by l ysle Gray of ABYC -i s lo use ordinary marine brass orbronz ep ipe fittings screwed down tightfrom insideand out befQ(eIhe top of the lank is added, and then glassed over trom ou tside. Baffles and all otherrequiremenls are as for melal lanks. Baffless hou ld be fiberglass, at leasl80 pe rcent of the lank-wall thicknessand bonded to the insideo f the tank with minimum 2-inch (50 mm) bonding angles la id on resin-rich 1.5-oz.lsq.ft.(457 91m 2) mal, and glassed over into place.The Best Tank MaterialIs there a "besl"materialfor fuel tanks? 1think so - it 's polyethy lene. Th is may be counterintuitive as somehowplastic seems less robust and less fireproof than metal or even FRP; however , po lyelh ylene tanks have beenprev en ancl tested since the earty 1970 s-s ome thirty yea rs. A U.S. Coast Guard/ABYC study peormed byaninclependent lab found no failures of any kind in pol y tank s. Former technical director of ABYC, Tom Hale,concluded that polyethylenefuel tanks pose no risk atal l ." Further, polyethy lene tanks have aU Ihe advantages ofFRP-Iower weight than metal tanks with zero possibility of oorrosionPol y tan ks have two drawbacks.One is that i t's di f ficull to make them strong enough in sizes over 80gallQns (3001)because baffles are nearly impossible to bui ld in . The second is Ihat poty tan ks are avallable onl y in a IImitedrangeo f sizes and shapes_Any form , ofcourse, can be fabricated, but too ling up for a cus tom poIy tan k reqUlresan inves lmentof roughly$3,000plus. Still,many off-the-shetfpoIyethylene tanks are made and will suit numerousapplications at Iow cost. If I cou ld find an existing poly tank that would dothe job, it wou ld be my first cho ice .Anolherthing to keep in mind aboul polyethytenetanks is that theyexpand after the i r f irst fill-up by about 2% in aHdirections . You musl anow for this inany lank installat ion and followthe manufacturer's mounting instructionscarefuUy .

Capacity Ga llo ns5 to 2020 to 8080 to 2oo200 10500500 lo 800

Capacity - l iters20 to 7575lo 300300 10750750to 19001900 to 3000

Thickness - Inche s0.1020.3DA0.5Thickness Mi llimeters2.55.17 .610.212.7

- . New SAFETYWARNING fa r 2006Fiberglass Gasaline Tanks are Damaged by EthanalWhat is Ethaool?Ethanol is thecommon term for ethyt alcohol alsot ermed "gra in a lcohol"- -Q.HeO.As ycu'd expect, ethyis commonly obtainedb y processing grain; though, almost .any type of vegetab le matter can be used toethyl alcohol . It's the sugaror starch in p1ant mater that's dlstJled into alcohol. Th is IS Ihe same chemicamakes alcoholic beverages alcoholic; rowever. alcohol also bums and makes a moderate!y useful fue l.ptants a re grown as needed, they are a renewable energy source (unlikepetroreum). This makes alcohopotential ahema tiveto petroleum-based fue!s such as gasoline.The word alcohol is used genericallywhen speaking of ethanol , but keep in mind there areother alcohomethanol (wood alcohol) and isopropyt alcohol (rubb ing alcohol). Methanol or methyl alcohol (CH30 H) is"wood alcohol"" because onginally was distilled from wood. Rubbing alcohol (4HeO) ts used to rub sormusd es, as the standard medicaldisinfectant, as antifreeze, as a solvent, among many other things . Nemethanol or rubbing alcoholis used in a mixture wrth gasoline as fuel , and both are po isons i f ingested .ethanol is eisc occasiona l ly used as a rubbing alcohol .Existing cers. tnJcks, and boats , almost universagy operate en gasoline or diesel fueI-both petroleum pDiese! eng nes -d ue to the way cese t engines function--can't bum alcoholin any fonn ; however almosgasoline enginescan safely run en the appropriale mixture of ga sotine and ethyt alcohol . In th lSuse , theof gasolinea nde thyt alcohol is generallytermed ethanot .1h e role ethytalcohol plays when mixed wrth gasot ine iscomp lex . It isn 't simply bumed but it replaces M(methyt tert-butyt ether), which in tum replaced tetra-ethyt Iead to reduce leacl emi ssions . The perpose ovaneesa dditives is primarily to increase the oxygen leve! in the fue! and so increasepeormance and rknock ing-increasing octane leve!. Such add itives are !hus oxygenates.Advantages of Ethanollh e alcohol in ethanolbums c1eany with Iow exhaust emissions , and it helpsthe gasohne bummore effAs we've seen ethyt alcohol is also renewable , and so--taken a1ltogether-it is appears t obe a green oenvironmentally-friendly energy source . There is sorne debate about the nel gains from using ethyt alcomake e!hanol , hQwever. It can be argued that the energy required to produce and transport the raw mat!hen distill the ethyl alcohol ; and propeny b1end it with gasoline--along with other practicar tactors-makenvironmentat gains less impressiYe.Ethanol Fuel Mandates - The New DevelopmentRegard less of any controversy that may exist about the merits of ethano l gasoline for t he environment oeconomy , many stales and t he U.S. Congress have mandated ethanol 's use a s a fuel. In fact-s ince almgasoline engines can run well on gasol ine with 10% ethyt alcohol blended in- -suchfuel is suddenly comooncept of ethanol, however, has beenaround for decadesa nd as an actual fuel - in very IImited dist ribsince the late 1970s. Unti l Ihe recent mandates , though , ethanol was rare. Now (in 2006), suddenly, i1 swidespread.Ten-percent ethanol (lhe blend of 10% ethyt alcohol by volume and gaso line)is called El 0 , tor ethyt .alcE20 is a blend with 20% alcohol. E85 is 85% ethanol and 15% gasoHne. l1's can only be usecl in eng lnessystems designedfor it . In any case, !he higher percentage blends are(as of 2006) less common becauare more likely to causesorne problems whenus ed i nexisting gaso line englnes and fue l systems.Ethanol Degrades Fiberg lass TanksAfI 01Ihe above has I ed t o a very new (in 2006) and largely unforeseen problem with fiberglass gaso linetanks. A sudden spate of tank aOO fue l difficul t ies have deve loped . Af ter researcha nd tesbng arrangedBoatlUS and several marine surveyorsdealing wrth odd fuel-system failures, these problems have beenback to !he alcohol in ethanol gasoline reading wrth ane! dissolving the res in in f iberglassfue l tank wallsprocess is chemicallys imilar to fiberglass osmotic btistering but much more aggressive and more pervatact, it 's been found lhat aHstandard fiberglassr eslns are attacked bye thanol . Tank waUs have been seweakeoed causing leaks , and styreneand re lated chemical byproduets dissolved in o r reacted with !hehavewo rked the ir way nto the eng ine wherethey have caused serious foullng problems

WestIS1\O lostitute -22- Wes tlawn lnstitute -


15/24

Fue) Systems For Boats- Course Number T I 501The leas t resrstant resin has been found lo be orthophthalie or orth -polyester followed by isophlhalie or tsopol yes ter , which holds up somewhal betler . Epoxy resin s are betler still . (1k now er notest s on vinylesterso far.)Regardless , EVERY ONE of these resms suffered ncticeabte degradation in contad with ethanol!00 NOTUSE FIBERGLASS GASOLlNE FUELTANKSUntil the eevent of widely-used ethanol, fiberglass gasoline fue! tanks were one c t ee best options possibe.There are many thousands of gasol ine-powered boats in servicewith fiberglassfuel tanks. This indudes vessersfrom top builders such as Bert ramand Hatteras . The new mandated usage of ethanol challges things . Al I thesetanksare suspect and YOU SHOU lO NOT OES IGN OR BUllO GASOUNE TANKS OF FIBERGLASS.

Fue) Sys tem s For Boats - Course NumbeDon' tGo Rubbery and Don 't Sp l i t lA final thi ng to keepin mind s t ha t rubber should never be used rorgaskets , beses. or paddingon yourfue l system. Petroleum -based products -l ike gasolin eene diesel---break down me rubber, ereating disaIeaks. Neoprene rs the propergasket and padding material . Oh yes, split gaskets of any materiala ren't aThe split would be a pctenuarpa th for a I eakThough there can be many specia lized ins and outs , if you to owthe aboye recommendatOns, you 'l Inesyslemthat meetsOf exeeeds CFR and ABYC requirements Better snn. itll be trouble free . A proper fuisn ' a l uxury, 's a neeessity .

Resin venc lorsdo say that there are resm to rmuaons wh ich can be used safeiy with ethanol ; however, these arenot widely known in !he boal i ng indust ryand currenUy are nol readilya vailable . Befareyou cou lddes ignand builda fiberglasstank for gasoli ne (safe for ethano l), youwould need lo ccnsun the resin vendar; select a suitableresm. make a sample test panel ; expose it for a long period of time to ethanol (months al Ieasl); and test thesamp le lo ensure that suffered no degradation of any type.The process of de veloping fibefglass tanks safe for ethanolwiUprobably be workedoul over the next severatyears: however-untll t h ~ y o u should avoid fiberglass gasohne tanks in new construetion. You must ersc beawa re of thi s potential problemi n exis ling vesses .When surveying, relrofrtting , repairing. Q{ simplyown ing orope rating an okJer gasoline boal, be sure to de term ine itsfuel-tankmaterial . If fiberglass , the tanks needs specialattention lo ensure they neven't suffered from ethanol degradation.Diesel Fiberglass Tanks - Still a Top ChoiceDiesel tank s are una f fected by this new development. The re's no alcohol equ iva lenl for any type far diese!.Biodiesel-the vegetable-based renewab le energy source that can be b1ended with orevenwholly replacepetroleum diesel-- is an oil n ot an alcohol. Biod iesel does no t degrade fiberglass reSins. Fiberglass dieseis fueltanks a re st i ll an excellent choice , with all the advantages of fibergtassta nks described in the preceding pages.

AppendixAGasoline Anti-5iphoningGasolinespills into the bilge are far more dangerous lhan diesel spns .Accordingty, all gas-eogine craft musl be equipped with ann spnco protection.John Eggers of EVM. Ine. explains that !he purpose of the anti-siphon protectionis to prevent emptying the tank shouldsomeone, say, accidental ly s tep on thefue! ne near the eng ine ancl break it off. If the broken linewere full of fuela ncldrooped down below the jevet of the fuel tank , i twouldl i terally siphon the tankccotents out into the b o a l ~ x t r e m e l y hazerdocs!Anli -siphon pro tection can be achieved by keepingan portio n s ot the fue! linesrigh t up lo the carburetor-above the tank top, making it of A1 hose , andsecuring the works so thal it can 'l fan downward l o crea le a siphon. Here , clearty,if the fue!line ruptures. the gas wi ll simply run harmlessty back.down "t o thetank. t f this approach is taken, a standard shut-offvalve al the tank take-off is slillrequired. It 's often difficult or inconven ienl to arrange the fue l system this way, inwhchcase an inexpensive (usuany $3 .00 , or less) anli-siphon devicemust be . " " a . . -installed in the fuertakeoff line righ t al t he tank. .The mosl common anli-siphondevice is a ba ll check valve thal prevents flow oul frorn !he tank at Iow sucaused by a leak) , bu! opens to a llow f10w at Ihe h igher suetion cre ated bythe fue l pump . A1temalively.aelectronically operaled shu t-off valve (a solenoid) can be instatled at the lank take-off and wired to the igSince the anti-siphon device prevenls all f\ow out from the tank un less the eng ine is running, no addit ionshut-off valve is requ ired . Anti-siphon fitlin g s are Iongerthan standardhose-barb connedors Insped lothese have in fact been installed .Appendix BSta inl ess Stee l Tank sSla inless steel hasbeen us ed successfull y fo r f uel l anks. but it was nol recommended by ABYC for manDr. Harry li psi tt. a professar of materials science, explains : The reason is corrosion al the welds ,or weMos lcommon marine-grade slainle ss, 304 or 18-8 (eontaining 8 percentcarbon) canla in both chromiumcarbonoVv1len Ihe mela l is heat ed t oover F ( 5 3 8 C) for we lding , the carbon is driven away and rchromium earbide form, with ehrom ium-depleted areas immediately adjacent. These Iwo -alloys - f orm acouple and can cause serious eorrosio n quiekly.The problemcan beconlroUed by using a stainlesssle e l wi th a strong carbide-fooning material added-This IS ava ilable as Iype 321 stai nless. Another alterna tive is lo use a Iow-earbon alloy . wi th less than 0.camon contentoType 316l (" l- for Iow carbon) or 317 l mee l this requirement. ABYC has recently accepand 317 l tanks (for diese!) if welding i s done according lo veryrigid specifications (see ABYC H-33) .Appendix eFlexible B ladder Ta nksAnother tank option is f lexible bladder tanks. Basically sacks of reinforced rubber-like fabric, these are aalmost every size and shape imaginab le . from 4 or 5 gal lons(15 1 up to 10.000 gal lons (38000 1) or morsources of marine bladder tanks in the U.S. are IMIRA, which imports the Nauta l ine of bladdertanksmanufactured by the French company Pennel, ancl Vetus den Ouden, lne. 60th companiesal so offer f leportable gasoline lanks-for outboard eran.Standard sizes and shapes are available, and cuslam tanks on speciat arder. Nauta tanksare fabricaled

W. . t1a" -D IDstitut. - REFERENCE PAPER 2 - R.v 2 -22b- \Vest1a",o Iostitute


16/24

Fue) Systems For Boats - Course Number T I 501 Fue) Systems For Boats - CourseNumbe

As a rule , if a tank's width is Iess Ihan 20% ot overa beam and Ihe capacity of the tank is less than 12%drsoecement. you can neg lect the free--surface eect for pleasure-craft work. Somet imes ; nowever. widare des irable to mee l specifie design goals. tf so , be sure lo divide up the lanks into two o r t hree separathwartships. An example of this is in the 66-foot (20 m) Kingtisher des i gn shown page 11. Here. iI wasadvantageous l o neve Ihe fue l lank s running ful l widlh atnwensnros aft of lhe master sla te room . In Ih ismain ceser lanks are divided intc tw o seprate lanks al the ce ntertine (wilh two addiliona l smaner ta nkoutboard) .Wheneve r you neve a lank wider Ihan 20% of overe be am or w ith a cepecy qreeter tnan 12% ofd i spyou should calcula le Ihe reduel ion in slabilily, ene use that re duced stability in aUyour omer slabi lity woperfectly coerect . you should do Ih is ter an tanks in all boets: bu! it general ly isn't requ ired if the ta nks arand of modesl capadty.)

should be avoided if poesuse.

Vllhere :GZ = righling a"" , ft . or mGM = meta cenl rie he ight. ft . or m6 = the angle of hee l in deg rees ("fT is Ih e Greek l elter T , pronoun ced "l hel a.")

GZ = GM x sine 6o,GM =GZ -:- sine 6

Stabil r ty is evaluated in le rms of GZ (nghbng arm) and GM dista nce lo tne metacenter M Irom the VCGceoter of gravi ly) or G . If you know ene you can easy find theother ter angles of heel up lo 10 deg reesformula is:

ATL re ".ulilled Ioam b1M


17/24

Fue) Systems fo r Boats - Course Number T I 501Contrary lo inl uilion, the total cepecty of the tan k does not affeetslabilily with regardto free-surface effect, neilherdoes the tank location (again, with regard lo i ree-scrrece effect.) lt doesn't meter how high or low, or how farinboard or outboard Ihe tank is localed. On ly the tank's individua l flu id surface area contributes lo the free-surfaceeect. Separate and distinctfrom !he free surface effect is the eect of the total weight (mass) of the fluid in thetank and the verticalIocalion of it's centerof gravity. High tanks will reduce stability when tun, while low tan ks wi llincrease stab ility when fu ll. This is the effect of the masso f the fluid noI free surface effect, which we're dealingwith nere .

Specffic Gravity Of Common Liquids(At 60- F,15.5- C)Li quid Specific GravityDiesel 0.852Gasoline 0.727Fresh Water 1.000Salt water 1.028l ube ()j I 0.921

Say , youhave a boatwilh a calculated GM 1- of 3.58 fl at a displacementof 2,156 ft.3 (61.6 toes. 137,984 lb.)with hatffull tanks. GZ 1-, for thisload condition, is Ihen 0.062 ft. and RM 1- is 0 .062 ft. x 137,984 lb. =8,555ft.lb . The boat has four tanks-2 far ceser ene 2 for fresh waler.CThe diese! and water tanks, in this case, areidentical port and starboard.) You'd fiod the effectiveGM as loIlows:The moment 01inertia of a rectangular ptanearea (you can find the lormula for other shapes in standardengineering texts) is:

Where (far evaluating tank free surface):b = the ~ g t h 01the tank rcee-o-e, ft. or mh = thewidth of the tank athwartships, ft . or mIn our case , the diese! tanksare 9 ft. long by 6.8 ft. wide athwartships . Thus the momenl 01ioertia of each tank is1= 9ft. x (6.8ft f + 12 = 235.8 f tThen

GM ( 235 .8 1\.' X 0.852 ) ftred = 3 - - - = 0.09 (for each diese! tank]2, J56 ft. 1.028Multiply by 2 for bolh diesel tanks =0.18ft. GMred (diesel)Thewa ter tanks are 2.5 ft. long 6.5 ft. wide athwartships. Thus Ihe moment of inertia for eaen tank is:t =- 2 .5ft . x (6 .5fti + 12 = 57.21 f tThen

GM ( 57.2 I ft X I.OOO)red= 3 - - = 0 .02 6 ft ,(fo reach water tank)2, 156 ft. 1.028

- -e

Fuel Systems For Boats - Course NumberAndGMetT= 3.58 t\.GMs - 0.23 1\. GMredT= 3.35 ft.This ts the loss in stabilily due to free-surrece eeect. and can be transtatee into reduced GZo r RM usingrelationship between GZ and GM aboye.In our case stability after free-surface effect is:GZ 1- = 3.35 ft. GM x sine 1- =0.058 fIRM l G = 0.058 11. GZ 1- x 137.984 lb. Disp. =- 8,067 fI.lb.This is a reduction in righling momen! of 6% due to free-scrtece effect.In metnc this W"OI1o:s out as fO/lows:Say , you have a boat with a calculated GM 1- er 1.0 91m at a displacement 0161 .05 m3 (62 .6 mTons, 62wrth half-fuUtanks. GZ 1-, fof this load cond iton, is Ihen 0.0190m, aodRM1 - is 0.0190 m x 62588kg =kgm . The boat has four tanks-2 far diese! and 2 for fresh waler .(The die se! and water tanks, inthiscasidentical port anclstarboard.) You'd f ind the effedive GM as lollows:The moment of inertia of a rectangularp1ane area (yau can find the formula lar other shapes in standardengineering texts) rs:1= bh3 + 12Where (lar evaluating tank free surrece):b = the Iength of!he tank jore-n-e, ft. or mh = the width ct the tank alhwartships, 11 . or mIn our case the diesel tank s are 2 .743 m long by 2.073 mwide athwartships. lhus the moment of inertiatank e:1= 2.743 m x (2.0 73 m)3 -:- 12 = 2.036Then

G ( 2.036 m' X O. 852 )M red = 3 -- = 0 .0276 m (for each diese! tank]61.05 m 1.028Multiply by 2 for both diesel tanks = 0.0552 m GMred (diesel)The water tanks are 0.762 m long 1.981 m wide alhwartships, Thuslhe moment of ine rtia lareach tank1= 0.762 m x (1.981 m)3 -:- 12 =0.494Then

( 0.494 m' X1.000 )GM red = 3 - - = 0 .0 0 7 8 7 ro ( roreach water tank)61.05 m 1.028Multiply by 2 lar both water tanks =0 ,01574 m GMred (water)

Mult ip ly by2 for both water tanks =- 0.052 ft. GMred (water)Now

Now

GMredT 0.18 ft.GMred(di"",') + 0.052 ft.GMred(" ",,) = 0.23 rl.

Wes tlal\'o Insti tu te - 26 -

GMredT= 0.0552 mGMred(di.,.., I)+0 .01574 mGMred(w.. ec) = 0.071mAnd

Westlawo Iostitute -


18/24

Nominal U.S.IPS or NPTPipes Size to Nom inal Memc"DN" Conversion ChartNom inal Pipe Nominal Pip eSize Siz e(Inches/U.S.) (Metric)

118" 6 mm3/16" 7 mm1/4" 8mm3/8" 10 mm112" 1Smm5/8" 18 mm314" 20mm1" 2Smm

1-1/4" 32 mm1-112" 40 mm2" somm

2-112" 65 mm3" BOmm3-112" 90mm4" 100mm

4-112" 11SmmS" 12Smm6" 150mm

Wcst lawn Institute

Fue l Systems For Boats - Course Numbcr

U.S. Pipe Thread StandardsJust as wi th thepipe itself there are several standards forthe threads on pipe and pipe fittings. In the U.most common pipethreads are NationaJPipe Thread (NPT), which isa tapered pipethread. and NationStandard Free-Fitting Straight Mechanical Pipe Thread (NPSM) . which is straight-not tapered . Taperedare used for sea led piping , while straightlh reads are for mechanical connections only. The dry-sealed, tthreadstandard is NPTF. This is tapered thread used forjo ining pipe to seall iquid tight without using seNPTF is the only pipe Ihreadw hich should be used for fuel-system piping. The NPTFand NPT threads ainterchangeable. but only t he NPTF is self seaJing AII the other pipe threads are incompatible with eachBe awarethat there are still other pipe-thread standards such as: GardenHose Thread (GHT); Fire HosCoupling (NST); and British StandardTaper Pipe Thread (BSPT). Oon't confusethese with NPTF.Pipethreads are also maleand female. Be surelo specify the gender required for yourspecificfitting. Ahoseadaptor to fit a 314-in. hose to a 3/4-in. NPS maJe pipe fitting. suited to fuel systems. would be spec"female 314-n. NPTF pipe to 3/4-in. hose connector."Note that the des ignation "NPr is often used in p lace of "I.P.S or "NPS" for U.S. pipe sizes , as the NPTonlygoes a pipe of the same size. Thus, a 1-in. I.P.S. Sched. 40 pipe (ON25mm) is also a l -in. NSched. 40 pipe (ON25 mm). since this would bethestandard thread fo r1 -in. Sched. 40 pipe (ON 25mm

have a colored bandal one end , while pipes of 4 to7 meters in length have a colored bandat either endU.S. ISO Pipe Oesignat ions - "ON " Pipe SizeThere's yet another pipe-size naming system. It is I SO pipe-size des ignations for U.S. IPS or NPS pipe."DN" pipe size as opposed to "DI pipe standard. "DW stands for diameler nominal. Under this systemNPS pipe is namedfor the do sest metric dimension to the nom inal pipe size. For instance 314in. IPS pi20mm pipe. lt's lheexactsame pipe . with real dimensions from the tabl e. I f thiswere standard weightoschedule-40 pipe itwouldbe 1.050 in. 0 .0 ., 0.113in. wall (26.7 mm 0 .0 . 2..87 mm wall ). The closestDpipe would be DIN 2448 26.9 x 2.9. NOTE: "ON and "OIN" pipe slandards appear Ihe same but Ihey ardifferent Below is atable of ONpipe sizes andtheir English-unit name equivalents. Note: The body of tuses DNpipe designations to give size for readers more comfortable inthe metric system.

6150

6.065154.15.761146.45.189131.8159.3

- 32-

4100

4.026102.33.82697.2

3.43887.3107.1

380

3.068n .92.90073.7

2.62666.682.5

2.46962.7

2.32359

2.12553.970.3

2-1/265

3/4 1 1-1/4 1-1/2 220 25 32 40 50

0 .8 24 1. 04 9 1.380 1.610 2.06721 26.6 35.1 40.9 52.5

0.742 0.957 1.278 1.500 1.93918.9 24.3 32.5 38.1 49.2

0.614 0.815 1.160 1.338 1.68915.6 20.7 29.5 34 42.822..3 28.5 37.2 43.1 60.3

Standard Metric - U.S. Pi1/215

0.62215.8

0.54613.8

0.46611.717.3

Nominal Pipe Size, in.Nominal Pi Size , mmSchedule 40, 1.0. in.Schedule40 , 1.0 . mmSchedule 80, 1.0 . in.Schedule 80, 1.0 . mmSchedule 160 , 1.0., in.Schedule 160, 1.0. mmOIN 2448. 1.0. mm

Traditional names for U.S. NPS p ipewal l th ickness or weighl are: Standard (Std), Extra Strong (XS), and DoubleExtra Strong (XXS). Std and schedu le 40 are the same in s izes up through 10 in. (24mm) In sizes aboye 10-in.(254 mm), Std has a constant a l of 3/8- inch (9.52 mm): an.d XS has a constant wa ll thickness of 1/2-inch (12.7mm). XXS has no correspondinq schedule number, but In srzes through 6-inch (152.4 mm), XXS has a wallthickness twice that of XS.

Appendix FIntem ati onal PipeStandards and Pipe-Size TablesThere are severaldifferent piping standards in use aroundthe world. This can b e a source of potential confusion.e n : r a l l y the s widel.y used standard is I.P.S. schedule pipe size r ir onp ipe size") or NPS r nominal pipeslz7 ). This categonzes l p by schedule ~ u m ~ e r or "weght." ost metal pipes of other rnaterats, including

s t a l n ~ e steel and alumln.um, follow the pipe-sjze standard, butthere are importanl excep ions, particularly forplastic pipe. Note that lubmg. as opposed to pipe. follows completely different size standards.In t he U.S. there are eleven schedules ranging frorn the thinnest wall at 5 through 10. 20. 30, 40. 60, 80. 100.120.140 to schedule 16D -thethickest wall. For nominal size piping 6 in. (150 mm) and smaller. schedule40(alsocal ed "standard weigh r in most sizes) is thenormal, standard pipe. and -vef)' rough ly - the schedulenumber of 40-v.:e ight pipe approximates. the inside diameter. American National Standards Institute (ANSI) pipestandards specify, say, S.40. for steel pipe (as opposed toi ron pipe) and 40S for stainless-the "S: before the~ c e d u l e number indi.cating. steel , and the "S" after t he number indicating stainless stee l. For the size of pipe usedIn fuel systems, the dirnensions of 40 and 80 pipe arethe same for thesematerials.

Fuel Systems Fo r Boa ts - Course Num ber TT 501

In s t . ~ pipe is manufacturedto DINstandards. and DIN 2448 pipe is standard pipe. DIN pipe isspecified In mitlirneters, as 0 .0 . and wall thickness . So a DIN 2448 pipe 25.4 mm 0 .0 . and 2.6 mm wall would bespecified as, "25.4 x 2.6:

Regardless of the "schedule" or "weight: all pipes of a specifiednominal diameter all have the same outsidea e t e r whatever the wall thickness. The outside diameter (0 .0 .) is larger than thenominal pipe size , as thenominal or schedule diameter very rough ly relates to the boreor 1 0 . As the schedule numberin creases. the 0 .0 .remains the sameand the wall thickness increases, so the inside diameler (1.0 .) orbore is smaller .F or example:- 4-in. schedul e 40 pipe has an outside diameter of 4.5 in., 0.237 in. wall . for an 1.0 . of 4.026 in.- 4 -i n. schedule 80 pipe has an outside diameter of 4.5 in. 0.337 in. wall. for an 1.0 . of 3.826 in.Or- 100 mmschedule 40 pipe has an outs ide diameter of 114.30 mm, 6.02 mm wall . for an 1.0. of 102.26 mm.- 100mm schedule 80 pipe hasan outside diameter of 114.30 mm. 8.56 mm wall, for an 1.0 . of 97.18 mm.

Only s c h ~ u e (wall thicknesses) 40 and 80 cover the full range of sizes from 1/8-in. (3 mm) up to 24-in. (600mm)nominal srzes , and are the most commonly used and available pipe.

Westlawn Institute

English-Unitllnch sizes in boldInthe U n i t e K i ~ g d o m piping to EN 10255, (steel tubes appropriate for screwin g to BS2 1 threads) is also usedwhere pipe screwed rather than f1anged. Thesea re generally referred to as "Blue Band" and "Red Band,"

c c o r d l n to their banded identification rnarks. The differentco lors referto the grade or "weight" of pipe: RedBand , belng heavy gr:ad7 I co.mmonly used for steam pipe applicati ons. Blue Band , being medium grade. iscommonlyused for ~ I distributcn systemsand low-pressure. low-temperature f luidapplications. The coloredbands are 50 mm wide, and their positionson the pipe give its length. Pipes less than 4 meters in length only


19/24

FuelSystems For Boats - Course Number TT 501GMefT = 1.091mGM , - 0.071 m GMredT= 1.01mThisis the lossin stabi li tydue lo free-surtece effect, andcan betranslated mto reduced GZ 01' RM usingIh erelationsh ip betweenGZ andGM aboye .In our casestabililyafterfree-surfaceeffect rs:GZ , . = 1.02 m GM x s ine , . =0.0178 mRM , . =0.0178 m G Z , . x 62588kg Oisp.=1114 kgmThis isa reduetionin nghting moment of 6% due to free -surface effect .Free Surface Effect and loading ConditionsKeep in rmnd that the free-swtece reduetion changes for various conditions of loadjng (fordifferenldisplacemenls). Using boat displacement to the DWL (O( to the expected ctaton waterline at 2J3rds load) teacequete for most smau-cra wor1< ;.however. for ccmmerctet prOjectsca refully lab ulaled GMs for differen t loadingccndmons will be required. Perforrmng stabilitycaleulationsf o ra ll reasonab le conditonsof Ioading and floodingare detailed and lime consuming. Usually, Ihese should be conducted using a software package , such as GHS,intended ter this purpose; however. you need lo understand Ihe principie aboye lo inle rpret!he resutls correcny .

.-..-e

Fuel Systems For Boats - Course Numb eAppendix EThe Common-Rail ManifoldThe term "manifold: as applied lo piping . Illeralty mean many partsor many paths 01 Channels. Any sycouecuco pipesfor directingflui d fIow is a "manifold . The tuel-piping manifoldon page 5 is typical examts a specific type of piping manifold that canoffer addedbenefitsin complex distribution systems. This imanifold where the source Of theretum areall branched off of cr intoa singlepipe. Thiss ingle pipeisc"common rail" 01' sometimesme "commen bus: 01' simply "bus .- Cornmon-ra il manifolds cansimplifyandistribution and control of piping ene allow ter the ease installation of buill-in spares for possiblefuture eTheday-tank piping schematicon page 5 wor1

Note that a valve rs snnrequired righl althe lank take-offb efore !he common rail. Notice how a spare br(01' several spares)can easily beadded to!he common rail.Specifying the Common RailThecommonrail 01' Ihe singlepipe which forms the distribulion l ine tethe branches to each componenleachretum) is usuanymade of pipe. It can be a single pipe with welded-on branchp ipes , or it could beof severa! sections of pipeconnected with pipeconoected in line with T-connectors. in series, to form thp i ~ s Sometimes a salid blockof metal is machined lo form the oommon rail. Inthis case, a longblocksalid stalnless ISbored alongits cenler lO forman intemal common-rail channel. The end is drilled andtaccepl themain inlet (01 outlet ) and the branchexits (01 inlets) are driDedand tappedat right angles (inlof !hecommon-rail block). For mosl ordinaryfue l-piping manifolds, plein pipe is !he mest cosl-effectiveaA.mistake in selting up a comrnon-rail mani fold is making the common-rail pipe lhe same diameler as !hpIpeS Ifyou slop lo think about, obviouslythe common ral has lo hand le !he combined fIow of AL l lhep i oombined . There canalso be someinlemarturbulenceand flow restriction due lo the sharpbendrequ lred by !he f luid inside the comrnon-rail manifold. For Ih is reason, theinternar crosssection area of

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i t " '3 .14

seclionarea1t

t 538mm2requiredcommon rail l.D. 2 x 1t = 44.2mm

Fuel Systems For Boats - Coursc Number

Wes wn stitute

seclionarearequiredcommonraill.D. =2 x . /-----

Common-Ra il anifo ld Have ny ApplicationsNote thatcommon-rail manifolds are useful in many applications . You can employthem for fresh-walerseawater inlake either attached to a seachest or to individual seacocks, or any o\her application with mupipes. Keep the common-rail-manifoldapproach in mind forgeneral use.

requiredcommon raill.D.=2 x ./- -- --

1tJ 2.33 sq.in.requiredcommon rail l.D. = 2 x 1t =1.722 in.

349.7 mm2x 4 branch pipes x 1.1 = 1538 mm2mnimum common-rail section area

We know that \heoutside diametershould be somewhat larger \han 44.2 mm. Referring tothe pipe tab e(Appendix F) we cal cu la te t ha t a 51x 3.2 pipe has an I.D. of 44.6 which will do nicely[51 mm- (2 x 3.244.6 mm).

it (21.1 mm I.D. + 2)2=349 .7 m

Referring to the pipe tables (Appendix F) we see \hat a 1-112-in Sched. 40 pipe has an I.D. of 1.610 in.small. So we usethe next sizeup: 2-in. Sched40 . O.D. 2.375 in., I.D. 2.067 in. This is as pictured in theaboye.Metric Common-Rail Sizing:T e inside diameter of!he 26.9 mm O.D. x 2.9 mmwall branch pipes is 26.9mm- (2 x 2.9 mmwall )=2I.D. The inside cross-section area for each is \hen:

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Fu I Systems For Boats - Coursc Num ber TT 501

Say you have a common rai l thal needs to feed two large main engines and a gen sel and\he common rail isfitted wilh four slandard-weighl 3/4-in . (or D1N 26.9 x 2.9) slainlessbranch pipes. includingthe spare. Seedrawingbelow, which isalsoa delail view of the common-rail feed manifold in \he schemalic on page 29aboye.

common-rail pipe needs lo be equal lo the total cross-section area of al l lhe branch pipes. plus 10%, or:Common-rail pipe section area = totalcombinedbranch-pipe seclion area x 1.1

English-Unit Common-Rail Sizing:Referring to the pipeIables (Appendix F). we see thal\h e inside diameter of\he Sched. 40, 3/4-in. branch pipes is0.824-in. I.D. each. The inside cross-section area for each is Ihen:

0.53 sq.in. x 4 branchpipes x 1.1 = 2.33 sq.in. minimum common-rail section area

The common-rat manifold aboye could be used exactly as shown; however. space andinslallation requirementsmay make it necessary to locate the common-rail, with it's branch pipes and valves, much farther from \he tank.This is fineas longas the pipingi s prope r1y supportedaga instbending and as long asflexible hosei s usedtoconnect to \ he engine and any o\her vibrating or moving components.

Note in the detail drawing aboye that the larger common-rail diameler must exlend \he full lenglh of the pipe from\he source. This means a largevalve, which takesup space and requiresa bigger take-off pipe. Il must beallowed for in the designandconstruction. The tank manufacturer has to install the large take-off pipe leadingdown ctose to thebottom of the tank (see page 17) as we ll as a suitable valve or valveattachment. Note thebrackets or supports required on the manifold piping to prevent flexing and cracking. NoteIhe screw-cap closurefitting on the sparebranch pipe for added proteclion against accidental spills. Nolice how the quarter-tum ballvalves allow you to immediately see if a valve is open or c1osed.

7t(0.824 in. 1.0. + 2)2= 0.53 sq.in.


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C O u I 1 ~ Amazon Ho& Rub ber Co

C om b inal io n Nip pl e fo rCo nn ec t ing Hos e to P ipe

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Fue) Sys tems Fo r Boats - Cou rse Num be

Hose Con nectorsHos e lo NPT F Pipe-Thread Connector

TOTAL Cl EARANCE .065 INCHES ONOJAM[l ERS (. 0525 INCHES EACH SFiII Pipe To Fill Hose Clearance

Hos e Mender or Jo inerto r Conneeting TwoSecticn s ot Hos e

F1LL PIPE (5"OOTH)

\,.,-------...,-+--T i " " 0 " " ' 2 e . ' l " , , W ; " HOSE INSIDEDIAMETERI

GREATER THAN 1 INCHIrdINOR OIA totETERIN THIS CASE ISOUTSIDE OIA t ETER

Westlawn lnstitute

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u.s. Plee-ThreadTableOD.Inches NPSor Engagemenl Threads-A- or IPS Pipe fortightpn l per"B" Size . in. -e-, in Inch0.3125 1116 0.2611 270.4050 llB 0.2639 270.5400 "' 0.4016 180.6750 318 0.4076 180.8400 112 0.5337 1.1.0500 3/. 0.5457 1.1.3150 1 0.6628 11.51.6600 1-1/4 0.7068 11.51.9000 1-112 0.7235 11.52.3750 2 0.7565 11.52.8750 2-112 1,1375 83.5000 3 1.2000 84 .0000 3-112 1.2500 84.5000 1.3000 8

If need lo determine Ihe size of U.S. pipe thread , measure eilher dimension A for male ftttings or B ror remetefittings. Enter thal in thechart and read Ihe NPS pipe size . Note Ihe threads per ineh (TPI). This changeswith mesize of pipe, TPI must be matchedex actly or the fitting wcn't worx

FuelSystems For Boats - Course Number T I 501

Pipe ThreadsCourtesy www.p1umbingwor1d.com

In smaller ezes. hose musl fit over barbed connectors (seepage 13). These connectors musl be carefullyselected lo matchthe pipe ane! hose. Be sure thal the 10 . of the hose-to-pe e connector does nol reducethe 10 .of the nre lo restnct flow.

Hose4o-Pipe Size Consideral ions'lllhile pipe ls dimensioned by the various sencus of standardsebove (and according to the tables tnat rouow).hose is dimensioned by nsiete ctameter. l.D. Thus if you werespecifying hose for a tenkf inl o mate wilh astandard 1-112-in, fill pipe . Theoutside r amete r of thepipe would be 1,90 in. and youd use 2in. 1.0. hose orspecify hose to matewit h 11I2-in. IPS (48.3 x 3.7) pipe. (See pages 13and 16)

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NominalPipe Size S ch edu le WallThickness Ins ida Diameter& Real No.0.0 . ;n mm in mm11S" .405" 40 0.068 1.73 0.269 6.83(10.3mm) 80 0.095 2.41 0.215 5.46- - - - -114" .540" 40 0.088 2.24 0.364 9.25(13.7mm) 80 0.119 3.02 0.302 7.67- - - - -318" .675" 40 0.091 2.31 0.493 12.52(17.1mm) 80 0.126 3.20 0.423 10.74- - . . -

5 0.065 1.65 0.710 18.03112" .840" 10 0.083 2.11 0_674 17.12(21.3mm) 40 0.109 2.77 0.622 15.80

80 0.147 3.73 0.546 13.875 0.065 1.65 0.920 23.373/4" 10 0.083 2.11 0.884 22.451.050"(26.7mm) 40 0.113 2.87 0.824 20.9380 0.154 3.91 0.742 18.855 0.065 1.65 1.185 30.10

1" 1.315" 10 0.109 2.77 1.097 27.86(33.4mm) 40 0.133 3.38 1.049 26.6480 0.179 4.55 0.957 24.315 0.065 1.65 1.530 36.861 114'10 0.109 2.77 1.442 36.631.660"(42.2mm ) 40 0.140 3_56 1.380 35.0580 0.191 4.85 1.278 32.465 0.065 1.65 1.770 44.961 1/2' 10 0.109 2.77 1.682 42 .721.900'(4S.3mm) 40 0.145 3.68 1.610 40.8980 0.200 5.08 1.500 38.105 0.065 1.65 2.245 57.02

2" 2.375" 10 0.109 2.77 2.157 54.79(60.3mm ) 40 0.154 3.91 2.067 52.5080 0.218 5.54 1.939 49.255 0.083 2.11 2.709 68.8121 12" 10 0.120 3.05 2 .635 66.932.875"(73.0mm) 40 0.203 5.16 2.469 62.7180 0.276 7.01 2.323 59.00

Fuel System s Fo r Boats - Course Numbe

Nom inalP ipe S ize Sch ed ule Wall Th icknes s Ins ide Diame ter& Real No.0 .0. ;n mm ;n mm5 0.083 2.11 3.334 84.68

3" 3.500" 10 0.120 3.05 3.260 82.80(S8.9mm) 40 0.216 5.49 3_068 77.9380 0.300 7.62 2.900 73.665 0 083 2.11 3.834 97.383 112" 10 0.1204.000" 3.05 3.760 95.50(101.6mm) 40 0.226 5.74 3.548 90.1280 0.318 8.08 3.364 85.455 0.083 2.11 4.334 110.10

4" 4.500" 10 0.120 3.05 4.260 108.20(114.3mm) 40 0.237 6.02 4.026 102.3080 0.337 8.56 3.826 97.205 0.109 2.77 5.345 135.80

5" 5.563" 10 0.134 3.40 5.295 134.50(141 .3mm) 40 0.258 6.55 5.047 128.2080 0.375 9.53 4.813 122.305 0.109 2.77 6.407 162.70

6" 6.625" 10 0.134 3.40 6.357 161.50(16S.3mm) 40 0.280 7.11 6.065 154.1080 0.432 10.97 5.761 146.305 0.109 2.77 8.407 213.50

8" 8.625" 10 0.148 3.76 8.329 211.60(219.1mm) 40 0.322 8.18 7.981 202.7080 0.500 12.70 7.625 193.705 0.134 3.40 10.482 266.2

10" 10.75" 10 0.165 4.19 10.420 264 .7(273.0mm) 40 0.365 9.27 10.020 254.580 0.500 12.70 9.750 247.75 0.156 3.96 12.438 315.9

12" 12.75" 10 0.180 4.57 12.390 314.7(323.8mm) 40 0.375 9.53 12.000 304.880 0.500 12.70 11.750 298.5

U.S. IPS (NPS) Pipe-Size Tabl es (con!.)

Westlawn Ins titute

e .-..-e

Fuel Systems For Boats - Course Number TT 501

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U.S. IPS (NPS) Pipe-Size Tables

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;-a=; I OIN 2448 piPE TABLE .10.21048.3mm 0 .0 .

Outslde diameter of Normalpipe, mm wallerres ttnckness omer Avalalbe Wall tmcxnesses (Note: Heavy Walls May Be 5pec al a rder)

1 2 3 mm 1 6 1.8 2 2.3 26 129 132 36 4 I 4.5 5 56 I 63 I 7 8_8 I 10 I 11 12 510 2 1 6 X X X X X13 5 1 8 X X X X X X X

18 1 8 X X X X X X X X17 2-1- 1 8 X X X X X X X X X

19 2 X X X X X X X X X20 2 X X X X X X X X X21 3 1 2 X X X X X X X X X

25 2 X X X X X X X X X X X25 . 2 X X X X X X X X X X X

26 9 1 1 23 X X X X X X X X X X X X30 28 X X X X X X X X X X X318 28 X X X X X X X X X X X

337 1 26 X X X X X X X X X X X38 26 X X X X X X X X X X X

'2 ' 1 2.6 X X X X X X X X X X X X44 5 26 X X X X X X X X X X X X X

48 3 I 1 26 X X X X X X X X X X X X X X

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Fuel Systems For Bo ats - Course Number T I 50 1Appendix GAppro ximate Feed and Retum Une Diameter - DieselBest practice is always gel the enginemenutec tcrer's recommendal ion for fuell ine diameter- feed and retum.Keep inmind, thal very k>ng O( complex fuel lines should goup a size in diameter. There will be instanceswhenyou needto estimate the line size and you can use the following. Remember erron the targesize. Vou can alwaysfit recucers . but youcen't overccrre the restnctco of pipe that istoo small. TIle drawback to going loo Iarge is theextra cost. more space used, and the added weight of the bigger plumbing . These considerationstoo areimportant too, so don't simply specify huge piping .Smalldiesel engirles useabout 114-in . NPT pipe minimum fO(feed and retum. upto around 200 hp.Dieseis from 200 hp to about400use 3J8-in. NPT going to 112in. al upper end , feed and retum.Dieseis from350 lo 650 hp use about 314-in NPT. feed and retum.Dieseis from 650 t o 1.200 hpuse about l -in . NPT. feed andreturn .Agajn, theengine manufaetureris the last word here. There is considerable vananoo . FO(inslance, a CAT 3

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