Ministry of DefenceDefence Standard 02-850 (NES 850)

Issue 1 Publication Date 1 April 2000

Requirements for the Dry Docking Slippingor Lifting of MOD Vessels

Incorporating NES 850 Category 3

Issue 1 Publication Date October 1989

Ministry of DefenceSea Systems Controllerate

Naval Engineering Standard

NES 850

Issue 1

October 1989

REQUIREMENTS FOR THE DRY DOCKING, SLIPPINGOR LIFTING OF MOD VESSELS

This NES Supersedes

Record Of Amendments

AMDT INSERTED BY DATE

1 1nl%, O0r r~

2

3

5

6

7

8

9

10

NAVAL ENGINEERING STANDARD 850

ISSUE 1

REQUIREMENTS FOR THE DRY DOCKING, SLIPPING OR LIFTING OF MOD VESSELS

The issue and use of this Standard

is authorized on behalf of the

Controller of the Navy by :

FOX 2749/366

(i)

rDirector of Technical Services (Warships)

®CROWN COPYRIGHT 1989Published by :Procurement Executive, Ministry of DefenceSea Systems ControllerateFoxhill, Bath

NES 850Issue 1

General

CONDITIONS OF RELEASE

1 . This Naval Engineering Standard (NES) has been prepared for the use of the Crownand of its contractors in the execution of contracts for the Crown and, subject tothe Unfair Contract Terms Act 1977, the Crown will not be liable in anywaywhatever where the Standard is used for any other purpose .

2 . This document is Crown Copyright and the information therein may be subject toCrown or third party rights . It is not to be released, reproduced or publishedwithout written permission of the MOD .

3.

The Crown reserves the right to amend or modify the contents of this NESwithout consulting or informing any holder .

4 . This NES may call for the use of processes, substances and procedures that maybe injurious to health if adequate precautions are not taken . It refers only totechnical suitability and in no way absolves either the supplier or the user fromstatutory obligations relating to health and safety at any stage of manufacture oruse .

5 .

Where attention is drawn to hazards, those quoted may not necessarily beexhaustive .

MOD Tender or Contract Process

6. This NES is the property of the Crown and unless otherwise authorized in writingby the MOD must be returned on completion of the contract, or submission of thetender, in connection with which it is issued .

7 . When this NES is used in connection with a tender or contract, the user is toensure that he is in possession of the appropriate version of each documentrelevant to each particular tender or contract. Enquiries in this connection maybe made of the local MOD(PE) Quality Assurance Representative .

8 . Reference in this NES to any related document means, in any invitation to tenderor contract, the edition and all amendments current at the date of such tender orcontract unless a specific edition is indicated .

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(ii)

CONTENTS

Page

Clause

AUTHORIZATION

(i)

CONDITIONS OF RELEASE

(ii)

CONTENTS

(iii)

INTRODUCTION

(vi)

SECTION 1

SCOPE

I

SECTION 2

RELATED DOCUMENTS

1

SECTION 3

PRELIMINARY REQUIREMENTS

2

Docking Plans - The Contract 0301Written Procedures 0304Certification by Contractor 0305Contractor's Nominated Responsible

0307Representatives

Dock Integrity 0310Firefighting Arrangements and Services 0311Stabilized Electrical Power 0314Retention of Records 0315Check that Vessel Fits 0316Stability Requirements 0317Longitudinal Distribution of Weight 0320Dry Docking a Structurally Damaged Ship 0321Dock Preparation

0324

SECTION 4

DOCK BLOCKS

7

Minimum Recommended Height

0401Maximum Permissible Height - Risk of

0402Tripping or Pillar Mode Failure

Dock Block Materials 0406Maximum Compressive Stresses 0407Condition of Timber Stacks 0408Composite Stacks 0409Alignment of Dock Blocks 0410Pits and Plinths 0414Side Blocks 0416Removal of Dock Blocks

0418

SECTION 5

DOCKING DOWN

11

Tidal Docks 0501Dry Docking Vessels with External Tile 0505Fits

Heel and Trim 0507Turning Propellers 0508Positioning of Vessel 0510Sueing 0511Temporary Steadying Shores for Docking 0514Conventional Submarines

Breast Shores

0517FOX 2

5g, d Cut-Up Shores

(iii)

0520

NES 850Issue 1

Page

Clause

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(iv)

Putting more than one Vessel into Dry DockWashing DownD495 Report - Fouling and Condition ofPaintwork

Responsibility for the VesselAdditional Requirements when Dry DockingSubmarines

SECTION 6

UNDOCKING 15

052205230524

05250527

060106050609

Pre-checks and CertificationUndocking Vessels with Sonar DomesD495 Report - On Completion of Docking

SECTION 7 UNDOCKING O&P CLASS AND UPHOLDER 16CLASS SUBMARINES

SECTION 8 NUCLEAR POWERED 17SUBMARINES

General 0801Dock Integrity 0808Cradles 0809Services 0812

SECTION 9

ROYAL FLEET AUXILIARIES 20

General 0901

SECTION 10 SLIPS 21

General 1001Restraint against Tipping 1005Keel Clearance 1006Slipping 1009Unslipping 1012

SECTION. 11 SHIPLIFTS AND SYNCROLIFTS 22

General 1101Written Procedures 1102

SECTION 12 FLOATING DOCKS 23

General 1201Additional Requirements 1202

SECTION 13 LIFTING BY CRANE 24

Agreement of MOD 1301Verification of Structural Strength 1302Lifting Gear 1303Weight of Craft 1305Support on Blocks 1306Replacing in Water 1307

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Page Clause

SECTION 14 CRAFT OF HARD CHINE 25CONSTRUCTION

General 1401Additional Requirements 1402

ANNEX A

CERTIFICATE TO BE COMPLETED 27BEFORE DOCKING DOWN

ANNEX B

CERTIFICATE TO BE COMPLETED 29BEFORE UNDOCKING

ANNEX C

AMMUNITION CERTIFICATE 31

ANNEX D

INFORMATION DOCUMENTS 33(NOT FOR CONTRACTORS USE)

ALPHABETICAL INDEX 35

NES 850Issue I

INTRODUCTION

1 . This Naval Engineering Standard (NES) is sponsored by the ProcurementExecutive, Ministry of Defence, Chief Above-water Systems Executive, SectionTW113 .

2 . It is to be applied as required by any Ministry of Defence contract for the dockingof HM Ships, HM Submarines, RFAs, RMAS, RNXS, Air Force, Army and all otherMOD owned ships, craft and vessels . It does not apply to small craft and boats of15m (50'0") or less length overall .

3 .

If this NES is found to be technically unsuitable for any particular requirementthe Sponsor is to be informed in writing of the circumstances .

4.

Any user of this NES, either within MOD or in industry, may propose anamendment to it. Proposals for amendments which are :

a .

not directly applicable to a particular contract are to be made to theSponsor of the NES

b . directly applicable to a particular contract are to be dealt with asspecified in the Contract . In the absence of a specific contract procedureproposals should be passed to the MOD Overseer/Representative .

5 .

No alteration is to be made to this NES except by the issue of a formalamendment .

6. Unless otherwise stated, reference in this NES to approval, approved, authorizedor similar terms means by the Controllerate of the Navy, Ministry of Defence, or(in the case of repairs/refits) by the Directorate General of Ship Refitting(DGSR) .

7 . Any significant amendments that may be made to this NES at a later date will beindicated by a vertical side line. Deletions will be indicated by 000 appearing atthe end of the line interval .

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NES 850Issue 1

1 .

SCOPE

0101 . a . This NES conveys to the Contractor the Ministry of Defence (MOD)requirements for drydocking, slipping, synchro lifting, or lifting by crane ofHM Ships, HM Submarines, RFAs, RMAS, RNXS, Air Force, Army and allother MOD owned ships, craft and vessels .

b.

It does not apply to hovercraft or to small craft and boats of 15m (50'0")overall length or less .

c .

It does not apply to beaching or "landing" on mud berths .

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2 . RELATED DOCUMENTS

0201 . Reference is made to :

Referred to in Clause

AQAP 1 Edition 3 Quality Control System Requirementsfor Industry

0309

AQAP 4 Edition 2 Inspection System Requirements forIndustry

0309

AQAP 9 Edition 1 Basic Inspection Requirements forIndustry

0309

BR 862 Naval Magazines and Explosives Regulations Annex C

BR 875 Regulations for Royal Fleet Auxiliaries 0902

BR 1754 Safety Regulations for Storing and HandlingPetroleum Oils

0525

BR 1762 Floating Docks Theory and Practice 1213

BR 3000 Marine Engineering Manual Annexes A & B

BR 3018 Technical Organisation and Administrationof Nuclear Submarines

0808 a, 1209

BR 3030 Radiological Controls for Nuclear Submarines 0816

BR 8647 Navy Department Regulations for FirePrevention and Fire Protection

0312

TINS Vol 1 Technical Instructions for NuclearSubmarines

0812

CPCA 82 Electrical Shore Supplies for NuclearSubmarines

0812

NES 53 Requirements for the provision of ShoreSupport Services for Surface Ships andSubmarines

0812

* NOTE: In course of preparation. When published will supersede stated document.

0202 . In the tender and procurement processes documents can be obtained as follows :

a .

British Standards

British Standards Institution, Linford Wood,Milton Keynes MK14 6LE .

b.

Defence Standards

D Stan 1, Kentigern House, 65 Brown St,Glasgow G2 8EX.

c.

Naval Engineering Standards - MOD Library Services (Bath), Foxhill, BathBAI 5AB.

d.

Other Documents

Tender or contract sponsor to advise .

MOD Library Services (Bath), Foxhill, Bath, BA1 5AB (Telephone Bath (0225)461211) can advise in cases of difficulty .

0203 . All applications to Ministry Establishments for related documents are to quote therelevant MOD Invitation to Tender or Contract Number and date, together withthe sponsoring Directorate and the Tender or Contract sponsor .

3.

PRELIMINARY REQUIREMENTS

Docking Plans-The Contract

0301 . Drawings of the arrangements for docking individual ships are known as "DockingPlans". When making arrangements to dock a vessel the requirements shown onthe Docking Plan are to be fully met. When there is conflict between a DockingPlan and this NES then the Docking Plan is to take precedence . Similarly if thereis conflict between the Contract and this NES (or the Docking Plan) then theContract is to take precedence. Any such conflict is to be drawn to the attentionof the MOD Overseer/Representative .

0302 . The Contractor is to take all reasonable actions with the MOD to ensure he is inpossession of the latest issue of the Docking Plan which is specific to the vessel(not class) .

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2 .

NES 850Issue I

Referred to in Clause

NES 110 Vol 1 Structures Manual 1208(*NES 154)

NES 145 Breakage 0303

NES 516 Guide to Lightning Protection in SurfaceShips

0313

Drg SDN 002609916 Docking Plan (AFD 59)Sheet l

0404

DG Ships 88 0406

Form D495 Report of Docking

0523, 0524, 0609,0701

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3.

NES 850Issue 1

0303 . a. For initial dry docking /und ocking of 1st of class new construction ships andsubmarines breakage is to be taken and recorded . The requirements ofNES 145 apply .

b .

During the build the contractor must assess the weight distribution beforeeach dry docking /u ndock ing .

Written Procedures

0304 . Contractors are to produce written procedures of their arrangements for the safedrydocking and undocking of MOD vessels . These procedures are to cover allrelevant requirements of this NES or as defined in the Contract and are toallocate specific responsibilities to specific company representatives. Theprocedures are to be produced before a dock preparation takes place and are to bemade available to the MOD Overseer/Representative at least 24 hours before thedrydocking is scheduled to commence . The responsibility for the correctness andadequacy of the written procedures rests with the main contractor who is to takedue account of any comment made by the MOD Overseer . Formal approval byMOD is not necessary (except as in Clauses 0801, 0802, 1202 and 1301) . The MODOverseer/Representative has the authority to waive this requirement in anemergency .

Certification by the Contractor

0305 . Annexes A, B and C show sample certificates that are to be completed asappropriate before drydocking or undocking a MOD vessel. Contractors may usealternative certificates but as a minimum they are to cover the applicablerequirements of Annexes A, B or C. Annexes A, B and C are not applicable tonew vessels that are being fitted out prior to MOD acceptance into service .

0306 . The Contractor is also to certify before a drydocking or undocking is commenced,that all the appropriate requirements of this NES, the Docking Plan and theContract have been met .

Contractor's Nominated Responsible Representatives

0307 . Before any preparations or detail planning for a dry docking, lifting or slippingtakes place the Contractor is to nominate in writing to the MODOverseer/Representative the responsible persons in Clauses 0308 and 0309. Theirqualifications and experience are to be acceptable to the MODOverseer/Representative .

0308 . The Contractor's nominated Docking Officer to be fully responsible for :

a .

the dock/shiplift/slipway being properly prepared ;

b .

the dry docking/lifting/slipping and the und ock ing /lowering /unslipp ingoperations ;

c . communications and liaison with the MOD Overseer/Representative, theCommanding Officer/Master and ship's staff on matters concerning thedrydocking/lifting/slipping and und ocking /lowering /u nslipp ing ;

d .

ensuring that all items in the vessel which have been maintained orrepaired by the Contractor are in a state acceptable for undocking .

0309 . The Contractor's nominated representative(s), suitably qualified and experiencedin Naval Architecture, to be fully responsible for :

NES 850Issue 1

a.

stability calculations regarding drydocking and undocking including takingaccount of changes of weights whilst in dock ;

b.

advising with respect to drydocking, lifting or slipping on matters ofstrength, stability, maintenance of form, watertight integrity etc ;

c. identifying those areas in which comprehensive instructions for the safeand efficient operation of docks, shiplifts and slipways need to be writtenor updated ;

d .

carrying out audits to establish whether the instructions on docking, liftingand slipping are understood and being implemented (AQAP 1, 4 or 9 refer .)

e . Participating in the investigation of any occurrences during drydocking,lifting or slipping in which the safety of the ship has been prejudiced .Participating in the formulation of remedial actions to be implemented bythe Contractor .

f . Monitoring loading during lift/lower on ship lift and during any transferoperation and ensuring that block loadings and imposed bending momentare within safe working limits .

Dock Integrity

0310 . The Contractor is responsible for the sound condition and correct operation of thedock/shiplift and all of its associated equipment and machinery (eg caisson/dockgate and pumping machinery and culverts) . The MOD Overseer/Representative isto be afforded all necessary assistance to satisfy himself regarding these mattersand any other regarding the integrity of the dock . - See also Clause 0808 .

Firefighting Arrangements and Services

0311 . Arrangements are to be made to provide to the vessel, once docked, all necessaryservices in accordance with the Contract . If specific requirements are not statedin the Contract then the Contractor is to provide a shore hydrant connection tothe ship's firemain and to the ship's spraying/flooding arrangements. Thisconnection is to provide water in sufficient volume and at sufficient pressure toactivate the ship's systems, in addition an adequate, fully operative alternativestandby supply is to be available. If the ship's systems are under construction,dismantled or under repair then alternative arrangements are to be made .

0312 . BR 8647 Chapter 6 is to apply except as modified by the contract. The contractoris to afford all necessary assistance to the RN Fire Prevention officers acting onbehalf of the MOD Overseer/Representative .

0313 . Earthing of lightning conductors on surface ships is to beNES 516 Section 6 or 7 .

in accordance with

Stabilized Electrical Power

0314. Most warships require a continuous supply of stabilized electrical power . Whenthe ship's generators cannot be run (eg because of lack of cooling water) thepower has to be supplied from ashore. The requirements are usually contained inthe Contract. Alternatively the MOD Overseer/Representatives will advise .

Retention of Records

0315 . The certificates and records required by this NES are to be retained by theContractor for the duration of the Contract and until the guarantee expires or as

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4 .

required by the contract . Upon request they are to be made available to theMOD.

Check that Vessel Fits

0316 . A documented record is to be made by the Contractor of a check that the ship isphysically able to enter the dock . The check is to be made well before the vesselis moved into the dock . Matters to be checked are to include :

LengthBeamDraught (see also Clause 0502 for additional requirements for tidal docks)Overhang of angled flight deckProjecting sponsonsUnderwater projections such as

Sonar DomesPropellersVoith Schneider UnitsStabilizersParavane shoeHydroplanesSubmarine lower rudder and speed distance probes (2 off)

Height of dock blocks above sill, taking account of run of dock .Interference with objects in dock bottom, eg high cradle blocks, docking

towersClearance to remove propellers, shafts, rudders, sonars etc .In covered docks - clearance above the vessel including removal of masts,periscopes etc

Depth of top of blocks below surface with shiplift fully loweredDepth of water in non tidal basinTidal constraints in tidal basin

Stability Requirement

0317 . a. The minimum stability requirements for the vessel while afloat may be laiddown elsewhere in Contract documents. Prior to dry docking a checkcalculation is to be made that the vessel's stability will remain positive justprior to grounding along the full length of keel . A record is to be retainedof this calculation . See Clause 0309 .

b . For nuclear submarines the nuclear safety authorities may imposeadditional constraints which would require calculations etc to demonstratethat stability is maintained throughout the docked period .

0318. a. Drydocking arrangements must always be made for the vessel to sue aftwith a trim less than 0 .5m (1'8") relative to the dock block declivity unlessspecific agreement in writing has been given by the MODOverseer/Representative to an alternative arrangement (except as allowedby Clause 1006 .)

b . A lesser trim by the stern could be required to ensure positive stability ongrounding on the dock blocks . These requirements of trim do not apply tonuclear powered submarines or other submarines docking in a cradle .

c . T2400 (UPHOLDER class) should be at a minimum draft and have anapproximate trim of 0 .3m (1'O") by the stern relative to dock blockdeclivity unless specific agreement in writing has been given by the MODOverseer/Representative to an alternative arrangement .

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NES 850Issue 1

NES 850Issue 1

0319. In the case of ships fitted with passive stabilizer systems the stabilizer tanks areto be emptied .

Longitudinal Distribution of Weight

0320. The curve of longitudinal distribution of weight for the vessel, obtained from theDocking Plan, is to be used to ascertain the dock block pressures over the bearingwidth and length of the keel . These pressures are not to exceed the maximumallowable compressive stresses for the dock block timber shown in Clause 0407 . Arecord of the calculated maximum pressures is to be retained by the Contractor .

Dry Docking a Structurally Damaged Ship

0321 . A vessel which has underwater damage is to be surveyed by diver(s) (providedthere is no imminent danger of sinking) to ascertain how the damage may affectthe drydocking. Particularly pertinent will be damage to the keel and anyprojecting steelwork . In preparing the dock, additional keel support blocks and/orside blocks may be needed before and abaft the damage to prevent the bearingpressures exceeding the maximum allowable compressive stresses given inClause 0404 . Conversely blocks may need to be removed in way of keel damageor projections. If compartments are flooded and cannot be emptied beforedrydocking the vessel, precautions must be taken to support the weight of waterby additional keel blocks or side blocks to prevent serious distortion or failure ofthe ship's structure. Removal of the water from the flooded compartment mustbe a priority. Consideration is to be given to reducing the speed of pumping outthe dock if this will allow flooded compartments to drain (or be pumped out) witha consequent reduction in structural strain . Siphoning is to be considered toaccelerate draining .

0322. When there is damage above the waterline care must be taken to place the breastshores on structure of sufficient strength. When the vessel's structure has beenseriously weakened consideration is to be given to emptying fuel and ballast tanksbefore docking the ship, provided this does not cause the ship to be unstable as shegrounds on the blocks.

0323. When it is intended to drydock a damaged ship with execessive trim in a gravingdock (because no other course of action is possible) or drydock a damaged ship infloating dock or heavy lift ship, where trim is adjusted to match the damagedship, the Design Authority is to be consulted .

Dock Preparation

0324. The dock is to be prepared in accordance with the requirements of the DockingPlan and of this NES . In addition the position of the fore end and of the after endof the vessel is to be marked on the coping (or other suitable part) of the dock .Alternatively, for those submarines where the ends are below the waterline, thedockside is to be given marks to align with datums on the submarine .

0325. After preparation the dock is to be inspected by the Contractor's nominatedDocking Officer to ensure correct dock preparation and to ensure that the dock isclear of all rubbish and debris before the dock is flooded . Additionally, the MODOverseer/Representative is to be afforded an opportunity to also carry out suchan inspection. A MOD inspection does not however, relieve the Contractor of hisfull responsibility for the drydocking . The time of flooding is to be notified inadvance to the MOD Overseer/Representative.

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6 .

NES 850Issue I

4. DOCK BLOCKS

Minimum Recommended Height

0401 . Dock Blocks are to be of sufficient height to allow survey of and work on theentire outer bottom of the vessel. In general it is recommended that blocksshould not be less than 1 .2m (4'O") high, a more usual and convenient height being1 .5m (5 10 11) .

Maximum Permissible Height-Risk of Tripping or Pillar Mode Failure

0402 . Hardwood blocks may be stacked up to 1 .5m (5'0") high made of material at least350mm (14") wide . The blocks are to be cribbed or double spurred shored, orsimilarly prevented from tripping for a length from the point of sueing, which isnot less than one sixth of the flat keel when hardwood caps are fitted or one thirdof the length of the flat keel when softwood caps are fitted . It is to be noted thatdagger planks are not acceptable alternatives to cribs or spur shores since they donot provide adequate block stability . This requirement includes the compositestacks referred to in Clause 0409 .

0403. Hardwood stacks up to 1 .5m (5'0") high made of material less than 350mm (14")but not less than 250mm (10") wide (NB . Stacks less than 250mm must not beused) require the following precautions to be taken :

a. The hardwood blocks are to be built to a minimum height of 600mm (24")and maximum height of 1 m (3'4") on either concrete plinths of minimumlength 3m (10'0") or steel bases,

or

b .

Blocks can be fully cribbed ie alternative layers placed longitudinally,

or

c. Double spur shoring (timber or steel) between the stacks . Shores are to benot less than 65mm (2 .5") square in section. The vertical supports are to befirmly secured to each block in the stack 450mm (18") either side of theML of the stack, and notched to take the top end of the diagonal shoreapproximately 150mm (6") from the top of the stack . A horizontal shore isrequired to be wedged between the foot of the diagonal shore and thevertical support at ground level,

or

d. Two flanged steel diaphragm plates at least 250mm (10") deep, 50mm (2")wide and 6mm (0 .25") thick are to be fixed longitudinally between eachstack of blocks . The diaphragm plates are to be secured between thesecond from the top blocks, 450mm (18") either side of ML,

or

e. Bolting two stacks together with through bolts . Nailing or "dogging" isinsufficient and not permitted. A minimum of 2 in No 20mm (0 .75") diabolts per pair of blocks are required .

0404 . Hardwood stacks above 1 .5m (5'0") high but less than 4m (13'1") high made ofmaterial not less than 300mm (12") wide require the following precautions to betaken :

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NES 850Issue 1Amdt 1

a. The blocks are to be fully cribbed throughout ie alternative layers placedlongitudinally . Stacks to be built up in groups of at least 1 .5m (5'0") longbut preferably 3m (10'0") long,

orb. Bolting 2 stacks together with through bolts . Nailing or "doggin " is

insufficient and not permitted . A minimum of 2 in No 20mm (0 .75") diabolts per pair of blocks are required,

orc. Steel bases similar to drawing No SDN 002609916 sheet 1 (Docking Plan -

AFD 59) or concrete plinths of minimum length 3m (10'0") . The minimumheight of wood blocks is to be 600mm (2'0") and the maximum 1 .2m (4'0") .If the blocks are 350mm (14") wide the maximum height of the timbers inthe stack may be increased to 1 .5m (5'0"),

ord . Where blocks are 350mm (14") wide and 1 .5m (5'0") high the height may be

increased by cribbing the extension layers . The first layer above the 1 .5m(5'0") being laid longitudinally. The longitudinal length is to be not lessthan 3 stack spacings .

Note: Dagger planks fixed to the ends of blocks and iron dogs used to connectblocks provide little strength and hence do not provide adequate insuranceagainst tripping .

0405 . Stacks more than 4m (13'1") high are not to be used without MOD approval .

Dock Block Materials

0406 . Dock Blocks and Capping Pieces are to be as follows :

a.

Centreline or side blocks

Oak stacksorOak on cast iron basesorOak on prefabricated steel basesorOak on concrete plinths not less than 3m (10'0") long - see Clause 0415orProprietary dock block systems (such as the Verolne Botlek Flexible Block)can be used when the docking plan specifies them . Generally it will beinappropriate to use such a system when the ship to be docked has specialrequirements, such as a cradle or where the rise of the outer bottomplating is excessive .

NB : If oak stacks are not available, elm or other suitable hardwood may beused. Mixing timbers in the same dock should, if possible, be avoided because oftheir differing compressions . DGS 88 defines material and characteristics oftypes of material eg English, Canadian or Wytch Elm .

b . Capping pieces to centreline blocks and side blocks under flat bottoms .Except as follows, these are to be of the same hardwood as the main stack .All frigates are normally drydocked on hardwood capping pieces . Howeverif the keel is known to be significantly unfair softwood capping pieces

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9.

NES 850Issue 1Amdt 1

50mm thick may be used . A mixture of hardwood and softwood cappingpieces is to be avoided . Vessels with wood keels or with flat keels less than460mm (18ins) wide are to be docked on softwood capping pieces 50mm (2")thick (100mm (4") thick in floating docks). Vessels with capped butts,external buttstraps or with bar keels are to be docked on softwood cappingpieces 100mm (4") thick.

c .

Capping pieces to shaped side blocks are to be of softwood not more than300mm (12ins) thick on the outboard side .

d . Nuclear powered submarines . In accordance with the relevant DockingPlan, these vessels are drydocked on cradles with rubber or softwoodcapping pieces shaped to the curvature of the hull in both the fore and aftand athwartships directions . The contractor is to carry out a full survey ofkeel shape whenever the dock is dry, correlated/annotated with thebreakage measurements .

Maximum Compressive Stresses

0407 . The width and spacing of dock blocks and their capping pieces must ensure thatbearing loads do not exceed 22kg/cm 2 (20 tons per sq ft) for oak or elm cappedblocks, and 16 .5kg/cm 2 (15 tons per sq ft) for softwood capped blocks . Blocks arenot to be more than 1 .2m (oft) apart in graving docks . In floating docks blocks areto be spaced in accordance with the design position for that dock. Additionalblocks if required are to be inserted between these positions or the blocks are tobe cribbed. Timbers must not normally be less than 350mm (14in) in the fore andaft direction (see Clause 0502) . In the region of very heavy loading the blockspacing is to be reduced or continuous blocking is to be used . In cases of vesselswith bar keels the preparation of the blocks may include the fitting under thecapping piece of a 20mm (0 .75in) thick MS plate the same length and width as thecapping piece in order to reduce damage to the blocks to a minimum . When thedocking plan or keel line of sight details include known or built-in deviation of thekeel, the calculation of dock block loadings must be based on the actual area ofthe keel in contact with the blocks during docking. If compensation is required itmust be specified in detail . It is to be noted that ships' structural overhangsforward and aft cause additional loads on the blocks during docking in the way ofthe forward and after cut ups, until the overhanging structure can be supported byvertical shores. This weight is to be assumed to affect the block loads for adistance forward of the after cut up equal to twice the length of the overhang andthe distribution to be of parabolic form .

Condition of Timber Stacks

0408. Timber dock blocks are to be sound, free of gross shakes and rot . Stacks are to bevertical and the individual blocks to be true with good faying surfaces . Theindividual pieces of timber are to be of a large practical size so that the crush ofthe stacks is uniform and hard spots avoided . Small packing pieces are notacceptable .

Composite Stacks

0409. Composite dock blocks are usually constructed of a fabricated steel base and mustbe surmounted by an oak or elm block at least 600mm (24ins) in depth (excludingcapping piece). If possible dock block stacks with different crushing potentialsare not to be intermixed ie composite stacks and all wood stacks are not to bemixed in the same dock . For the same reason oak and elm cappings are not to bemixed in the same dock .

NES 850Issue 1

Alignment of Dock Blocks

0410. The upper surface of capping pieces are to be aligned fore and aft to within+ 5mm. This alignment is to be for the full length of the vessels keel. Acceptablemethods of alignment are :

outwinding battenslight boxestheodoliteslasers

0411 . Due to wire sag, taught wires are to be used over short distances only .

0412. Athwartships the upper surfaces of capping pieces are to be horizontal, fair andlevel. See also Clause 0810 (docking cradle profile) .

0413. Where the keel is not straight either by design or distortion the blocks are to beprofiled to the known shape of the keel and their setting to be checked by atimber mould at least 12m (40'0") long with the top edge a set distance above theplane of the top of straight dock blocks .

Pits and Plinths

0414 . When 1 .5m (5'0") high dock blocks are insufficient for large protruding sonardomes or for rudder removal recourse may be necessary to a pit or to plinths .Sufficient side clearance is to be provided for removal/replacement of domes .For dock blocks over 1 .5m (5.0") high refer to Clause 0404 .

0415 . Plinths are commonly of masonry, concrete or steel and are surmounted by dockblocks. The dock blocks above the plinths must be no more than 1 .5m (5'0") highand must be cribbed or double spur shored as required in Clause 0402 . The plinthsmust be of sufficient continuous length along the dock to give stability to thedock blocks against tripping ie never less than 3m (10'0") in length .

Side Blocks

0416 . Side blocks may be used only if authorized by the Docking Plan . When docking avessel with underwater damage side blocks can additionally be authorized by theMinistry Overseer/MOD Representative when the width of the dock is such thatthe use of breast shores is not practical . They are to be erected and made in thesame way as centreline blocks, but where they are higher than 1 .5m (5'0") they areto be cribbed in groups about 6 (20'0") to 9m (30'0") apart and length not less than3m (10'0") . For vessels with steep rise of floor considerable profiling may benecessary to achieve the maximum area of contact bewteen hull and side blocks .

0417 . Great care is to be taken to avoid side blocks taking the initial drydocking load ieside blocks must not be set high .

Removal of Dock Blocks

0418. When a vessel is in dock and removal of blocks is necessary for access to the keel,every third block may be removed provided that the consequent pressure on theremaining blocks does not exceed the maximum compressive stresses inClause 0407 .

0419. In order to minimize the risk of tripping the two remaining in place must retaintheir associated cribbing or double spur shoring . Similar requirements apply tothe removal of side dock blocks.

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0420. If it is essential to remove more keel blocks (eg to renew a keel plate) thencompensating side blocks must be employed . The pressures on the remaining keelblocks and on the compensatory side blocks must not exceed the maximumcompressive stresses in Clause 0407 . These side blocks are to be positionedbeneath bulkheads, longitudinals, frames or other strength members and checkmeasurements made so that the ship's form is maintained .

0421 . On completion of work and before undocking, all keel blocks are to be replacedand hardened up . Procedures for this operation are to be provided as prescribed inClause 0304 .

5. DOCKING DOWN

Tidal Docks

0501 . These provisions do not apply to docks in the Mediterranean or other areas wheretidal fluctuations are comparatively small .

0502 . When MOD vessels are drydocked in tidal docks they are to be placed in the dockonly on a rising tide and the caisson (dock gate) is to be replaced at least one hourbefore high water . Similarly undocking is also to take place at least one hourbefore high water to allow for the possibility of redocking should the need arise .

0503. The planning for the drydocking must include the provision of tidal informationwhich accurately predicts tidal flow across the dock entrance and the height ofthe tide above the dock sill at the various relevant times .

0504. MOD vessels are not to be left afloat in tidal docks unless there is no possibilityof bottoming .

Dry Docking Vessels with External Tile Fits

0505 . a . Prior to drydocking any vessel with an externally applied rubber/acousticdamping tile fit, any blocks in way of tiles are to be lined with polythenesheeting to avoid damage by stiction to tiles whilst undocking .

b . Adequate provision must be made for block height/shape on any vessel witha rubber tile fit, consideration being given to the reduction in the tilethickness due to loading. (See Clause 0505 c .)

c. For vessels with a "rubber" tile fit careful consideration must be given tothe tile loading in way of dock blocks as excessive loads will structurallydamage the tiles and consequently reduce performance characteristics .Guidance should be sought from NA221 for safe design loads on the varioustile types prior to drydocking any vessel with such a fit .

0506. The flow of water entering the dock is to be controlled until the top of the dockblocks are under water to avoid the possibility of tripping .

Heel and Trim

0507 . a . Before a MOD vessel is docked down it must be ascertained that it isupright . An angle of heel must be eliminated either by the transfer ofliquids within the vessel or by the use of temporary weights . See Clauses0317-0319 for requirements of trim and stability .

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b.

For nuclear powered submarines the contract requirements will usuallystipulate permissible limits for heel and trim .

Turning Propellers

0508 . In order not to disturb the dock blocks and to avoid washing debris into the caissongroove, the propellers (or other propulsion) of the vessel being drydocked must notbe turned within the dock . This restriction also applies to any accompanying oradjacent craft such as tugs etc .

0509. Prior to docking down, the propellers, stabilisers, hydroplanes and rudders are tobe turned to their drydocking positions and restrained from further movement .

Positioning of Vessel

0510. The methods of moving the vessel into and out of the dock and positioning thevessel correctly with respect to the dock block arrangement is to be determinedby the Contractor . The method chosen must be approved by the MOD Overseer/Representative and must not create a risk of damage to the vessel or herequipments.

Sueing

0511 . Except for nuclear powered submarines and other submarines drydocked in cradlesand as allowed by Clause 0904 the vessel will sue first at the after cut up (ACU) .As soon as the ACU has sued on the dock blocks the breast shores (seeClauses 0515-0517) closest to the cut up are to be put in place (packed but notwedged thus allowing movement whilst the vessel's trim changes until she has suedalong the full keel length). This is intended to ensure that during the criticalperiod of reduced stability the vessel may be steadied if the need unexpectedlyarises .

0512. As soon as the vessel sues along her full keel length all breast shores are to bespeedily put in place and wedges hardened up. Until this has been done the waterlevel must not be allowed to fall any further . Vessels with fixed domes are tohave the domes pumped out at rate which minimizes the difference in waterlevels inside and outside the dome .

0513. As soon as the dock is dry an inspection is to be carried out to verify the vessel iscorrectly placed on the blocks and that arrangements are intact and correct .

Temporary Steadying Shores for Docking Conventional Submarines

0514. The breast shores for conventional submarines (of the Oberon or Porpoise types)are usually at about the waterline or lower at maximum beam . For this reason itis not practicable to place the breast shores in position until the water has fallenby a considerable amount. It is therefore necessary to give support to thesubmarine by temporary steadying shores placed against the lower part of the fin(at the precise strong position shown on the Docking Plan).

0515. The temporary steadying shores are to be placed when the submarines sues aft butare to be kept slack . From the time of sueing aft until the keel is fully in contactwith the blocks along its length care must be taken to ensure that shores do notjam between the fin and the dock altars on which they rest .

0516 . a.

After the submarine has sued along the full length of the keel thetemporary steadying shores are to be hardened up . They may be kept in

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place until the submarine is undocked . If removed during the period indock they must be replaced and hardened up before undocking .

b. For 'O' and 'P' class submarines drydocked in cradles the cradle blocks willbear on tank sides not pressure hull . Blocks are to be arranged to allow agap of (0.25") from the hull form . If this is not taken up by out oftolerance of the hull then it must be made good by wedging at the earliestopportunity.

Breast Shores

0517. Breast shores can be heavily loaded . They are to be of a suitable material such assteel or timber which is free from shakes or rot. Shores are to be of sufficientcross section to ensure that buckling failure cannot occur in the event ofunexpected high axial loading. Shores of 150mm (6") diameter are sometimesadequate when very short lengths are required but most docks demand a minimumof 300mm (1'0") square .

0518. When in place, the heads (ie the ship ends of the shores) of breast shores are to behigher than the heels (ie the dry dock altar ends of the shores) so that the shorescannot jam when the vessel undocks .

0519. Breast shores are to be placed, as indicated on the Docking Plan, at points of highhull strength such as on bulkheads or decks . Unless otherwise indicated on theDocking Plan they are to be as high as practicable on the hull . Procedures(Clause 0304) are to provide for periodic inspection of shoring arrangementsduring the period in dock and to include hardening up requirements/precautions.

Bilge and Cut-Up Shores

0520. When bilge and cut-up shores are required, they are to be put in place as soon aspracticable. The period during which the vessel is unsupported is to be kept to anabsolute minimum .

0521 . The statements in Clause 0517 regarding the materials, sizes and strengths ofbreast shores apply equally to bilge and cut-up shores . For GRP vessels the headsof breast, cut-up and bilge shores are to be padded to prevent hull damage .

Putting more than one Vessel into Dry Dock

0522. When two or more vessels of similar draughts are being drydocked down at thesame time, care must be taken to ensure the second vessel does not accidently suewhilst attending to the first . The Contractor is to satisfy the MOD Overseer/Representative before the event that sufficient precautions will be taken .

Washing Down

0523. a. Washing down is usually best done from the dock bottom using highpressure fresh water hoses . It is to be carried out as soon as practicable,but not until the survey information on the extent of outer bottom foulinghas been obtained for recording on the form D495 .

b . Contractors are to take precautions to contain arisings which result fromwashing down so as to control/prevent pollution which the toxins andpoisons in anti-fouling coatings would otherwise cause .

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D495 Report-Fouling and Condition of Paintwork

0524 . Information needed to complete the D495 Report of Docking (eg extent of fouling,condition of paintwork etc) is to be obtained by the Contractor as soon as thevessel has been docked down .

Responsibility for the Vessel

0525 . Unless otherwise provided for in the contract, the Contractor is responsible forthe safety and stability of the vessel for the entire time the vessel is in dock -from the time the stem passes through the dock entrance until it leaves onundocking. All necessary assistance will be given to the Contractor by Ships'Staffs including :

a. obtaining the consent of the Contractor's nominated Docking Officerbefore transferring ballast, fuel, water and other liquids ; moving weights ;and consuming fuel and fresh water etc . Refer to BR 1754 for movementof fuels ;

b .

giving the Contractor's nominated Docking Officer full details of weightsand liquids moved or consumed ;

c .

when requested supplying hydrostatic and stability curves, tank tables andother data held onboard .

0526 . The Contractor is responsible for the timely repair of any damage caused byhimself, his agents, servants or sub-contractors etc . Such repairs are to be to astandard agreed by the MOD Overseer/Representative .

Additional Requirements when Dry Docking Submarines

0527 . The Contractor's nominated Docking Officer is to inform the Commanding Officer(PNO during build) of the time when it is expected that the submarine will belanded on the blocks, and the time when flooding is to be started when undockingand of the required condition of trim . The Commanding Officer is to be requestedto inform the Contractor's nominated Docking Officer when the submarine is atthe required trim . The Commanding Officer is to be further requested not tochange this trim without consulting the contractor's nominated Docking Officer .

0528. The Contractor's nominated Docking Officer is to have previously agreed with theCommanding officer (PNO during build) that a responsible ship's officer will bepresent to take charge on the submarine and to arrange for any changes in thedisposition of weights which may be found necessary .

0529 . When the drydocking operation is complete the Contractor's nominated DockingOfficer is to inform the Commanding Officer (PNO during build) that thesubmarine is docked down and shored .

0530 . It is desirable to crack open main Kingston valves (0 and P class) before thevessel is docked down owing to the possible difficulty in operating these fittingswhen a submarine is on the blocks .

0531 . All main tanks are to be blown before entering the dock, those fitted withKingston valves having these left open if the procedure described in Clause 0530has been adopted .

0532 . When a submarine has no crew onboard the Contractor's nominated DockingOfficer is to take full responsibility for the dry docking and undocking of the

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vessel. He is to ensure that the vessel is brought to the required state of trimbefore the operation is begun .

6. UNDOCKING

Pre-checks and Certification

0601 . The Certificate in Annex B is to be fully completed before water is admitted forundocking. This certificate is not applicable to new construction vessels that arebeing fitted out prior to MOD acceptance into service .

0602 . Before undocking, the dock is to be cleared of all arisings, stores and rubbish toprevent anything being washed up into seatubes etc and jamming valves . Blocksecurings are to be checked, especially if they have been removed and replaced.

0603. Propellers, stabilisers, hydroplanes and rudders are to be in their docking positionsand restrained from further movement .

0604 . Before undocking, the dock is to be inspected by the Contractors NominatedDocking Officer to ensure that the requirements of Clauses 0602 and 0603 havebeen met. Additionally the MOD Overseer/Representative is to be afforded theopportunity to also carry out such an inspection . A MOD inspection does nothowever, relieve the Contractor of his full responsibility for the undocking . Thetime of commencement of undocking is to be notified in advance to the MODOverseer/Representative .

Undocking Vessels with Sonar Domes

0605 . When undocking HM Ships fitted with retractable sonar hull outfits it is necessaryfor the dome to be lowered a suitable distance during the initial stages of floodingthe dock and/or rig fine mesh nets to prevent foreign matter floating up throughthe keel aperture .

Particular care is to be taken that when the water level reaches approximately1 .5m (5'0") over the top of the dock blocks the domes are immediately rehoused .The responsibility for ensuring that this is done rests with the CommandingOfficer or, for a vessel not in commisson, the Contractor, who is to arrange for animmediate report to be made to the Contractor's nominated Docking Officer ifany difficulties are being experienced in housing the dome, in order that measurescan be taken to prevent the ship becoming waterborne . A report is always to bemade to the Contractor's nominated Docking Officer when the dome has beenhoused .

0606 . A fixed sonar dome is to be filled with water whilst undocking, at a rate whichminimizes the difference in water level, between the inside and outside of thedome.

0607. Both the handbook of the hull outfit concerned and the installation instructionslay down the precautions appropriate to each particular hull outfit, and both areto be consulted as necessary .

0608. Immediately all underwater valves are covered pumping is to cease until a carefulsearch for leaks inside the vessel is completed, and these made good .

D495 Reports-On Completion of Docking

0609. The D495 Report of Docking is to be completed within one week after undocking .

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7. UNDOCKING O&P CLASS AND UPHOLDER CLASS SUBMARINES

0701 . The D495 Report of Docking is to be completed within one week after undocking .

0702. The Contractor's nominated Docking Officer is to ascertain from the CommandingOfficer, (PNO during build) before commencing undocking, that all main tankKingston valves are shut .

0703 . Guidance List of Conditions When Undocking Patrol/Conventional Submarines(where relevant)

The guidance list is as follows :

a .

All pressure hull welding (inserts and blanks) to be completed.

b.

Pressure tight blanks to be fitted where equipment has yet to be installed .

c .

Hull valves and cocks below waterline to have been tested, lashed shut andopen ends blanked .

d .

Hull valves above the waterline not tested to be blanked .

e . All pressure hull hatches to be shut and clipped except for the conningtower, upper and lower, which, although left open, are to be checked forsatisfactory closing. Where a hatch has not been installed, a pressure tightblank is to be fitted . The upper and lower conning tower hatches are to beproved at the vacuum test, and any service leads subsequently passedthrough the conning tower are to have breaking connections adjacent to theupper hatch .

f . The boundaries of escape of compartments are to have been testedsatisfactorily . Main bulkheads of untested compartments are to beexamined for watertight integrity, blanks being fitted where necessary .Main bulkhead doors to be operable, open and unobstructed .

Fuel, ballast auxiliary and compensating tanks to have been satisfactorilytested on completion of all work within .

g .

h .

Main vents to be shut and harbour cottered . Kingston valves to be shut .Vent and Kingston valve hand levers to be readily available .

i .

Electrical cable hull glands to be completed below waterline . Incompleteassemblies above the waterline to be blanked .

All underwater external gratings and fairings to be fitted. Greasingarrangements below waterline to be proved correct .

k .

Outer boundary vacuum test to have been satisfactorily completed .

1 .

Main and trim line systems complete and operationally tested .

m.

Auxiliary diesel driven pump to be secured to casing and connected to mainline cable wash down connection .

n .

The LP blower, ballast pump, appropriate hydraulic/telemotor pump andone air loaded accumulator (ALA) to be operational .

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Hydraulic/telemotor system to be sufficiently complete for the operationof bow and stern caps, main vents and Kingston valves . The forward andaft telemotor hand pumps to be available for pressurising bow and sterncap operating systems etc .

At least two HP air groups to be fully charged and available for directblowing, blowing HP to LP, salvage blows, one ALA and main propellershaft emergency seals .

q .

LP air system to be complete and operationally tested .

r . Torpedo tube control arrangements for bow and stern caps where fitted tobe complete and tested . Tube fittings to be complete or blanked.Bow/stern caps and rear doors where fitted to be shut .

s. Linkages to the rudder and after hydroplanes to be checked and secure withall greasing proved. Rudder and hydroplanes to be secured in centralposition .

t .

All external work on main shafting and stern seals to be complete andtested.

u .

Garbage ejector to be installed or tube blanked externally .

v . For 0 and P class submarines . (Requirements for SSK UPHOLDER classwill be incorporated in due course. Pending such instructions the designauthority is to be consulted via the Ministry Overseer/Representative .)Hull Outfit 3 watertight trunk to be water pressure tested and the 719Directing Gear cage vacuum tested.

w.

Sonar hydrophones fitted and hull glands packed .

x.

Clinometers to be fitted .

y.

Damage control lighting to be provided.

z .

Trim to be in accordance with statement issued by dockyard/shipyardDesign Division.

8. NUCLEAR POWERED SUBMARINES

General

0801 . For new construction nuclear powered submarines the Shipbuilding Contractor isto produce written drydocking and undocking instructions which are to besubmitted to PNO for MOD comment . MOD comment is to be incorporated intothe instructions before commencement of the drydocking/undocking procedures .

0802. HM nuclear powered submarines in commission will normally be drydocked atDevonport, Rosyth or Faslane . The Contractors at Devonport and Rosyth are toprepare Nuclear Procedures containing the pre-requisites and detailed instructionsfor drydocking and undocking nuclear powered submarines . The MOD Overseer/Representative is to be afforded the opportunity to be represented on theProcedure Authorization Groups approving these nuclear procedures . The NuclearProcedure Co-ordinator for these nuclear procedures is to be the Contractor'snominated Docking Officer.

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0803 . Should another shiprepair yard be required to drydock a nuclear poweredsubmarine, a liaison officer or team will normally be provided by SuperintendentShips DGSR and/or FOSM and/or the Squadron concerned .

0804 . Details of the docking requirements, and the necessary shore services, adaptors,hoses, flooding bonnets etc are available, if needed, from Superintendent ShipsDGSR . For Fleet Dockings this information is to be obtained from the designatedrepair authority . Such information can be obtained via the MOD Overseer/Representative .

0805 . The certificates at Annexes A and B are to be expanded to include the nuclearsubmarine requirements (eg nuclear safety requirements, housing of the secondarypropulsion unit etc) .

0806 . Nuclear safety justification and clearance of the drydocking facility by thedirectorate of Naval Policy and Security is an essential requirement for SSNs andSSBNs.

0807 . The maintenance of stability control during the entire period in dock is essential .

Dock Integrity

0808 . Unless stated otherwise in the contract or specification :

a .

The graving dock/floating dock/shiplift is to be the subject of an approvedNuclear Safety Report in accordance with BR 3018 Annex A.

b . The maintenance of the graving dock/floating dock/shiplift, caisson(s) orgate and pumping, flooding and draining arrangements is to be covered by aplanned maintenance system acceptable to the MOD Overseer/Representative .

c. The operation of the graving dock/floating dock/shiplift, caisson(s) or gateand pumping, flooding and draining arrangements are to be covered bywritten operating procedures acceptable to the MOD Overseer/Representative .

Cradles

0809 . Nuclear powered submarines are drydocked into cradles, details of which areshown on the relevant Docking Plans. The option also exists for conventionalsubmarines. See also Clause 0516 b .

0810. Before each drydocking operation the cradle is to be examined for rot, splits andshakes etc in accordance with Clause 0405 . Unsound timber is to be replaced withgood timber before the drydocking operation . Wherever practicable the othersections and clauses of this NES are to apply. The cradle is also to be checked (aspart of the inspection at Clause 0325) for accuracy of profile and cross-sectionbefore each drydocking .

0811 . Special care is needed to protect the acoustic tile outfit and(see Clause 0505 c) .

Services

0812 . The following shore services, essential for nuclear safety are to have been testedand connected (except that the supply of demineralized water may be available at

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sonar flank arrays,

e.

A supply of demineralized water, available at agreed notice ;

f .

Other services and supplies as required by the Contract, NES 53 orTechnical Instructions for Nuclear Submarines (TINS) .

0813. The connection and listing of the shore services as in Clause 0812 and all otherrelevant nuclear safety drydocking pre-requisites are to be included as pre-requisites in the nuclear procedures for drydocking the nuclear poweredsubmarine.

0814. The following additional facilities are required if the crew arenuclear powered submarine during the drydocking period .

a .

Fresh water supplies of up to 4000 gallons per day .

NES 850Issue 1

agreed notice) in accordance with the procedures called for in Clause 0801 beforedrydocking a nuclear powered submarine in a shiplift, floating or graving dock :

a . Primary alternative and stand-by electrical shore supplies are to be inaccordance with NES 53 and Technical Instructions for Nuclear Submarines(TINS) Volume 1 CPCA MEMO 82 ;

b.

A primary supply of salt or fresh water for reactor cooling and acompletely independent standby supply;

c .

A facility for discharge of radioactive primary coolant, ie portable effluenttank or connection to an effluent treatment plant ;

d .

Nuclear accident communications ;

(i) From the Control Room to the Emergency Monitoring Headquarters(EMHQ), or where there is no EMHQ, the Port Headquarters orequivalent .

(ii)

From the Manoeuvring Room to the shore Electrical Power SystemsControl Room .

to live aboard the

b.

Suitable connections to the combined sewage and slop drain tank overboarddischarge systems .

0815. Before commencing to pump the dock, the Contractor's nominated DockingOfficer is to have received from the Commanding Officer confirmation in writingthat the reactor plant and containment are in the state specified in the pre-requisites to the Nuclear Docking Procedure and that flooding bonnets and hosesfor cooling water are fitted in the required positions and functioning satisfactorily(unless the bonnets and hoses have been fitted by the Contractor) .

0816. When the submarine has been docked down, the Contractor is to arrange aradiation survey of the submarine hull, dock walls and bottom in the vicinity ofthe reactor compartment . The Contractor is to erect radiological controlled areaor supervised area signs as necessary - BR 3030(2) Section 2 Chapter 1 refers .

0817. All relevant undocking nuclear safety pre-requisites are to be included as pre-requisites in the nuclear procedure for undocking the nuclear powered submarines .

0818. Where work on or in connection with nuclear powered submarines is to beundertaken by a non-nuclear repair contractor, the Commanding Officer of thesubmarine is responsible for the scrutiny of intended work for nuclear and

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radiological implication . No work with a nuclear implication is to be carried outby a non-nuclear contractor without prior MOD approval .

9.

ROYAL FLEET AUXILIARIES

General

0901 . Other relevant sections and clauses in this NES are also applicable to thedrydocking and undocking of Royal Fleet Auxiliaries (RFAs) .

0902 . Trim and stability requirements for drydocking and undocking RFAs are as statedelsewhere in this NES but are additionally to be discussed and agreed with theMOD Technical Superintendent for the RFA.BR 875 refers .

0903 . When bottom plugs are to be removed, a plug account is to be opened andannotated in agreement with the RFA Technical Superintendent .

0904 . When a RFA is undocked a joint inspection by the Contractor and the RFATechnical Superintendent of the ship's bottom and the dock bottom is to becarried out immediately before water is admitted into the dock . If for any reasonthe inspection takes place earlier, a watchkeeper is to be stationed at the drydock to prevent any person or persons taking action which would affect the safetyof the vessel . The watchkeeper is not to leave his station until flooding hasstarted .

The dock inspection party will commence their inspection at the forward end ofthe ship and work their way aft checking each plug in turn and marking it off onthe plug account . Attention is to be paid to all plugs not only those known to havebeen removed. Particular attention is to be paid to the latter to ascertain thatthey are properly grommeted and secure .

0905 . When the water in the dry dock has covered the sea suction valves and before thevessel floats off the dock blocks, the Contractor's nominated Docking Officer isto request of the RFA Technical Superintendent (or in his absence the ship's ChiefEngineer) to arrange an internal inspection to ascertain that no leakage is takingplace. This inspection is to include all ship's side valves . Tanks, compartments orother spaces which cannot be visually examined are to be sounded to prove theyare secure and no leakage is taking place .

0906 . The ship's Chief Engineer is to be asked to verify before undocking that all ship'sside valves are in good order and lashed in the closed positions ; that gratingsecuring arrangements, rudder and associated parts, stern gland and outsidefastenings are correct and in good order .

0907. During the period of dry docking and during any tank testing, bilge and side shoresare to be fitted in way of ballasted tanks .

0908 . Shores and blocks are to be checked daily .

0909. The Contractor is to give the RFA Technical Superintendent and the Officer incharge of the ship, at least 24 hours notice in writing of drydocking or undocking .

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10.

SLIPS

General

1001 . Smaller vessels may be slipped instead of drydocked . Other sections and clausesin this NES are applicable also to slipping in so far as they are practicable,particularly those relating to blocks and their loading .

1002. The written procedures required by Clause 0304 are to include measures to ensurethat the vessel is adequately supported along the keel without keel overhang ateither end.

1003. If satisfactory service is to be obtained from a slipway it needs to be properlymaintained and the area kept free of obstruction, mud, dirt, rubbish etc . Before aMOD vessel is slipped, the Contractor's slipway is to have been the subject of asatisfactory survey during the preceding twelve months . The survey is to havebeen carried out jointly with a surveyor suitably qualified in civil engineering .The survey is to cover concrete aprons, piling, security of tracks, rails and rollerpaths, underwater sheaves, hauling wires, security of hauling winch etc . Anyrequired remedial action is to have been taken . The Contractor will be requiredto provide evidence that the survey and remedial action has been completedsatisfactorily. A valid certificate of test for winch machinery is to be madeavailable for inspection prior to slipping/unclipping vessels .

1004 . The maintenance undertaken is also to include preservation of the cradlemembers, servicing of the winch machinery and condition survey of the wires,wheels, rollers, pawls, pullage, sheaves and rail clips etc .

Restraint against Tipping

1005. A slip cradle is to provide restraint against the vessel tipping during slipping orunslipping. At least two side support structures are to be attached to each side ofthe mobile platform, positioned to prevent a heel of more than 5° and of strengthsufficient to resist a horizontal force of 4W sin 5 0 applied at the points of contactwith the vessel, where W is the weight of the vessel .

Keel Clearance

1006. Draught boards indicating the depth of water available over the top of theforemost and aftermost carriage block when the cradle is down are to be fitted .

1007. Draught and displacement of the vessel are to be checked and the craft lightenedif necessary to bring it within the lifting capacity of the slipway . An initialclearance of at least 150mm (6") is to be allowed between the bottom of the craftand the top of the capping block on the carriage when the craft is correctlypositioned over the cradle . When slipping on slipways leading from busy, tidal, oropen waters the minimum clearance between the keel and cradle is to be 300mm(12") and great care is to be taken to ensure that the wash from passing ships andboats does not cause the craft to surge and to ground prematurely .

1008 . Pre-slipping planning is to include a check that external hull fittings will be clearof the supporting blocks .

Slipping

1009. As the craft is drawn out of the water, wedges are to be packed tightly betweenthe bottom of the craft and cradle blocks where hard bearing is not obtained, in

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- 11. SHIPLIFTS AND SYNCROLIFTS

General

order to distribute the weight of the craft as evenly as possible over the lengthand breadth of the cradle .

1010. When slipping a vessel onto a cradle of two or more parts (ie collapsible cradle)the vessel is to be positioned with a clearance of 150mm (6") over the first blockwhen in the correct location and the vessel is to be so trimmed that she will notsue all along until the cradle has been fully extended and the vessel supported atthe correct positions in accordance with the slipping instructions .

1011 . Where pawls are fitted, the cradle is to be held by the engagement of one or morepawls in the pawl rack . Spur shores are to be placed and wedged up from the floorof the slip to the cradle, whether or not pawls are fitted .

Unslipping

1012. Precautions are to be taken when lowering the cradle to prevent it taking charge .Backhaul wires are to be kept clear of the cradle track . Particular precautionsare to be taken when the cradle is in two or more sections (ie collapsible cradle) .As the vessel takes to the water, care is to be taken to prevent the wedgesjamming between the deck edge and the dolphins . Just prior to the vessel floatingoff the cradle the winch is to be stopped to allow a careful search for leaks to bemade.

1101 . Shiplifts may be used if the written permission of the MOD has been previouslyobtained for the type of vessel and the particular lift. Permission will only begranted if a full safety and reliability assessment based on fault free analysis ofthe lift's power and control systems demonstrates acceptable levels of risk to thevessel. Other sections and clauses in this NES are applicable also to Shiplifts sofar as they are practicable .

Written Procedures

1102. Procedures as required by Clause 0304 are to be written by the Contractor beforeany MOD vessel is lifted or lowered or transported on the associated system .These written procedures are to include contingencies satisfactory to the MODOverseer/Representative for the failure of the lift at a mid position (especially intidal waters) .

1103. Before lifting a vessel the loading limits for the ship must be calculated and, withthe addition of suitable margins, displayed at the shiplift console for comparisonwith loadings measured by the lift. Weights of shiplift beams and cradles mustobviously be taken into account. The loading limits are :

a.

The maximum individual block loading that the local ship structure cansupport.

b. The loading pattern which combined with the ships weight distribution,exceed the acceptable longitudinal bending moment at any section of thevessel .

Note that during the lift the varying loading along the lift will cause thelift to go out of level because high loads will stretch the lift ropes morethan low loads. The lift will stop when the highest (lowest loaded) beam

FOX 2749/366

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NES 850Issue 1

reaches ground level and then it must be levelled by varying the remainingbeams. Because of the stiffness of vessel and dock preparation, this willgive large loading increases in the highly loaded beams with very smallmovement and therefore very quickly . A considerable margin is thereforerequired from the limiting loadings to allow levelling to be undertakensafely .

1104. As Clause 1103, the equivalent loadings for any transfer system must becalculated, displayed on the transfer systems load monitoring equipment, andsatisfactory arrangements made to monitor it throughout operation of the system .

1105. Operating/Emergency procedures must give full details of the recover actions tobe taken if any of the loading limits are exceeded .

12. FLOATING DOCKS

General

1201 . Other sections and clauses in this NES are to be instigated where applicable .

Additional Requirements

1202. MOD owned floating docks (whether operated by MOD or a Contractor) are to beoperated completely in accordance with MOD instructions for the dock. Writtenprocedures in accordance with Clauses 0304 and 0802 are required andadditionally are to be approved by MOD .

1203 . Floating docks owned by Contractors or sub-contractors may be used if thewritten permission of the MOD has been previously obtained for the particulardock and the type of vessel. The granting of such permission will depend on anumber of factors including the scrutiny (but not necessarily approval) of thewritten dock operating procedures (see Clauses 0304 and 0802) and verificationthat the dock structure, equipment, systems and stability meet agreed standards .

1204. It is to be noted that ships structural overhangs forward and after cause additionalloads on the blocks during docking in the way of the forward and after cut ups,until the overhanging structure can be supported by vertical shores . Theadditional loadings have particular relevance to floating docks in that they maylocally exceed the weight per foot loadings of the dock structure .

1205 . Dock Operating Instructions for MOD owned floating docks give maximumpermissible displacements for bearing lengths of keels, for ships without curves oflongitudinal distribution of weight (load curves) and these should never beexceeded .

1206 . Where a curve of longitudinal distribution of weight (load curve) is available for avessel then this is to be superimposed on the net lift curve of the dock . If the liftcurve exceeds the load curve over its whole length then it is safe to dock thatvessel (the load curve will have isolated peaks due to concentrated weights - it isacceptable to mean these peaks over the length of one dock ballast tank) .

1207. The requirements of Clause 0320 apply .

1208. If the ship's curve of longitudinal distribution of weight does not show theadditional loadings on the blocks and dock structure due to overhanging shipstructure at the cut-ups, then these additional loads are to be calculated . Amethod of calculations is shown in NES 110 Vol 1 -Structures Manual .

FOX 2749/366 2 3.

NES 850Issue 1

1209 . Floating docks used for drydocking nuclear submarines require safety reportsproviding justification of the facility . The requirements for the administration ofthe Safety Report are specified in BR 3018 . The report is to concentrate onstating how the nuclear safety of the submarine(s) will be ensured through theinterfaces between it and the dock and will be completed for endorsement bynuclear safety authorities. Key hazards which need safeguarding against arethose events which cause unplanned heel, trim or loading of the dock, hencetransfer of these effects to the interface arrangements and the submarine . Thedock design, operating and maintence authorities are to combine to produce thecompleted report .

1210. When pumping floating docks a methodical plan is always to be used . It is to becarried out in such a manner that longitudinal and transverse deflections of thedock are prevented and is done by removing water from the tanks below thelargest loads . This is essential to prevent excessive bending moments and thepossible rupturing of tanks and reduction of dock strength .

1211 . In MOD owned floating docks deflections are never to be allowed to exceed thepermissible amounts shown in the Dock Operating Instructions .

1212 . The centre of gravity of a floating dock is usually before or abaft the longitudinalcentre of buoyancy . Without a vessel, the dock is kept level by flooding the tanksone end more than the other, such that the combined centre of gravity of dockand water is coincident with the longitudinal centre line (centre of buoyancy) .When drydocking, the ship is so positioned that its weight trimming moment(about the dock centre line) balances that of the dock . This enables the maximumamount of water to be pumped out to obtain maximum lift .

1213 . Further information can be obtained from BR 1762 - Floating Docks Theory andPractice .

13. LIFTING BY CRANE(NB This NES does not apply to small craft and boats whose overall length is 15m(50'0") or less)

Agreement of MOD

1301 . No MOD craft or vessels are to be lifted by crane, without the written authorityof the MOD Project Manager . In certain circumstances this authority will bebacked by a drawing showing the approved method of lifting . Written proceduresin accordance with Clause 0304 are required and additionally are to be approvedby MOD.

Verification of Structural Strength

1302 . A contractor's request for permission to lift by crane is to be accompanied by acertificate, signed by a competent Naval Architect, verifying that the vessel hassufficient structural strength to withstand the proposed method of lifting .

Lifting Gear

1303 . The Contractor is to ensure that strops, shackles and other lifting gear are to bein good condition and within test date .

FOX 2749/366 24 .

NES 850Issue 1

1304. A contractor's request for permission to lift by crane is to be accompanied by acalculation to show that the materials, equipment and rig he proposes to use iscapable of the task.

Weight of Craft

1305 . The displacement of the craft or vessel is to be recorded before attempting tolift. A comparison is to be made between the displacement and the intended (ordesigned) lifting weight. In no circumstances is the intended (or designed) liftingweight to be exceeded.

Support on Blocks

1306 . All other sections and clauses in this NES relating to dock block and shoringsupport are applicable so far as they are practicable .

Replacing in Water

1307. Particular care is to be taken to record variations of the weight of the vesselwhilst out of the water and action taken to prevent the intended (or designed)lifting weight being exceeded . Clauses 0601-0608 are also to be satisfied . Priorto removing lifting arrangements a careful search is to be made internally forleaks.

14. CRAFT OF HARD CHINE CONSTRUCTION

General

1401 . Other sections and clauses in this NES are applicable so far as they areappropriate. This NES does not apply to small craft and boats whose overalllength is 15m (50'0") or less .

Additional Requirements

1402 . When drydocking, slipping or lifting craft of hard chine construction under 30m(100'0") in length, the boats are to be docked on special soft topped side chocksshaped to suit the underwater form of the boat. The boats are not to bedrydocked on their middle lines . The chocks are to be arranged on, or as near aspossible to, bulkheads. The Docking Plan is to be consulted to determine theextent of chocking in the vicinity of sonar domes or other projections . A workingclearance of 225mm (8.75") is to be allowed transversely between the inner endsof chocks and the extremities of projections . Care must therefore be taken thatthe middle line of the boat does not swing off the middle line of the chock cradleby more than 150mm (6") .

1403 . The Docking Plan is also to be consulted regarding the longitudinal disposition ofchocks and their minimum height .

1404 . During slipping operations a minimum vertical clearance of 225mm (8 .75") is to bemaintained between the bottom of projections and any fixed member of thecradle. See also Clauses 1001 to 1012 .

1405 . When craft are lifted, tanks are to be emptied and heavy weights such as weaponsand stores are to be removed . Only an approved lifting rig is to be used whenslinging the vessel . See also Clauses 1301 to 1307 .

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NES 850Issue 1

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26.

ANNEX A

DOCKING CERTIFICATEFROM: (ENTER THE CONTRACTOR'S NAME

AND ADDRESS)To:The Commanding Officer/Master

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .HMS/RFA Date

DOCKING CERTIFICATE

It is requested that the certificates below may be completed, signed and returnedto me beforeHMS/RFA is to be docked in NoDock at on

The ship is to be upright and trimmedby the bow/stern .The condition of tanks should be as attached (Docking in floating docks only) .Attention is drawn to changes of weight whilst in dock . No large changes of

weight or moment are to be carried out by Ship's Staff without prior notice to theContractor's nominated Docking Officer and until his concurrence in the proposedchanges has been obtained . (BR 3000 Marine Engineering Manual Art 0509) .The nominated representative of the Contractor responsible for the docking andundocking is Mr(Telephone No)(Address as above) .

SignedManager

NES 850Issue 1

I, Weapons and Electrical Engineer Officer, of HMS/RFAhereby certify that the logs and sonar domes of HMS arein the housed position and will remain so until docked .

. . . . . . . . . . . . . . . . . . . . . . .Date and Time

I, Marine Engineer Officer of HMS/RFAhereby certify thatthe propellers and stabilizers of HMS/RFAare in the correctdocking position, that the ship is upright and at the correct trim, and that the ruddersare secured amidships and will remain so until docked .

. . . . . . . . . . . . . . . . . . . . . . .Date and Time

. . . . . . . . . . . . . . . . . . . . . . .

Date

NOTE: Permission of the Port Authority is required before a ship can enter dock withExplosive Stores FFO, Dieso, Avgas, Avcat or Avpin on board .

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27.

ANNEX A

NES 850Issue 1

ANNEX AFOX 2749/366

28.

To:The Commanding Officer/Master

NES 850Issue I

ANNEX BUNDOCKING CERTIFICATE

FROM: (ENTER THE CONTRACTOR'S NAMEAND ADDRESS)

• . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .• . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .•

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .HMS/RFA Date

The Contractor's Undocking Certificate below is communicated for yourinformation .

It is requested that the ship's undocking certificate below be completed, signedand returned toMr byon

. . . . . . . . . . . . . . . . . . . . . . .

Date

Signed (Manager)

CONTRACTOR'S UNDOCKING CERTIFICATEWe hereby certify that the stability of the vessel, taking into account changes

of weights by the contractor and changes of weights by the Commanding Officer issatisfactory for undocking .

We hereby certify that the valves, submerged torpedo tubes, sonar gear and allother underwater fittings and openings in HMS/RFAwhich have been under repair by the contractor have been examined and found to bewell and properly constructed and fitted, and are all tight .

All these valves and openings are closed and the ship is ready for undocking .The flooding of the dock will start aton

Signed(Contractor's nominated Docking Officer)

Date

SHIPS UNDOCKING CERTIFICATEWe, the undermentioned officers of HMS/RFAcertify

that the valves, submerged torpedo tubes, sonar gear and all the other underwater openingsof HMS/RFAwhich have been under examination or repairby ship's staff, have been found to be well and properly constructed and fitted and allvalves and other openings for which we are respectively responsible whether repaired ornot, are properly closed .

The logs, sonar domes and stabilizers are correctly housed : the rudder issecured amidships and the propellers are in the correct docking position with shaftlocked: anchors are housed and secure : Derricks, davits and cranes turned in andsecure : .

. . . . . . . . . . . . . . . . . . . . . . . . . .Marine Engineer Officer

Weapons Engineer Officer

Date

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29.

ANNEX B

NES 850Issue 1

CHANGES OF WEIGHTS IN DOCKWith reference to BR 3000 Marine Engineering Manual Art 0509,

I hereby certify that (delete as necessary) :(a)

No changes have been made by the Ship's Staff while the ship has been indry dock, in the distribution of weights, which will affect the draught, heel, trim andstability of the ship on being undocked .(b)

Changes made by Ship's Staff to the distribution of weights while theship has been in dock have been reported toin writing, and two clear working days' notice has been given .(c)

It is confirmed that the only changes made in the distribution of weightssince the report made in accordance with (b) are those which have been made atthe request of the contractor to counteract any earlier weight changes .

. . . . . . . . . . . . . . . . . . . . . . . . . .Commanding Officer

Date

ANNEX BFOX 2749/366

30.

1, Commanding Officer of HMS/RFA certify that :

* (a)

all explosive stores have been disembarked .

or

* (b)

explosive stores as detailed in the appendix attached have beenretained onboard, and

(i)

permission has been obtained from the Port Authority inaccordance with local Port instructions .(ii)

regulations laid down in NM & ER's (BR 862) Chapter 7 will becomplied with .(iii) arrangements have been made to meet the requirements forfiremains delivery rate and pressure .

Signed

Date

*delete as appropriate

Notes

(a)

List of compartments containing explosive stores are to be shown overleaf .(b)

Permission from Port Authority to retain FFO, Dieso, Avcat and Avpin, Avgas,Explosive Stores on board during docking is also required to be attached .

ANNEX C

AMMUNITION CERTIFICATEFROM: (ENTER THE CONTRACTOR'S NAME

AND ADDRESS)To:The Commanding Officer/Master

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .HMS/RFA Date

at

It is requested that the certificate below be completed, signed and returnedto me before HMS/RFAis docked in Nodockaton

Signed(Manager)

NES 850Issue 1

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ANNEX C

NES 850Issue 1

ANNEX CFOX 2749/366

32.

ANNEX D

INFORMATION DOCUMENTS (Not for Contractor's Use)

MOD(Naval) EstablishmentsBR 8593

Ship Refit, Repair, Maintenance and Associated Procedures .DGSR

Refitting Manual Vols land IIIMaritime Guide

Published annually by Lloyds Register of Shipping giving docksizes etc worldwide .

Admiralty Tide TablesSSCP 54

Procedures, Practices and Instructions for Principle NavalOverseers (Not for issue to Contractors)

3 .

In the tender and procurement processes documents can be obtained as follows :

a .

British Standards

British Standards Institution, Linford Wood,Milton Keynes, MK 14 6LE

b .

Defence Standards

D Stan 1, Kentigern House, 65 BrownStreet, Glasgow, G2 8EX

c .

Naval Engineering Standards - MOD Library Services (Bath), Foxhill,Bath, BA1 5AB

d . .

Other Documents

Tender or contract sponsor to advise .

MOD Library Services (Bath), Foxhill, Bath, BA1 5AB (Telephone Bath (0225)461211 can advise in cases of difficulty .

4 . All applications to Ministry establishments for related documents are to quote therelevant MOD Invitation to Tender or Contract number and date, together withthe sponsoring Directorate and the Tender or Contract Sponsor .

FOX 2749/366

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33 .ANNEX D

1 . The following documents are unlikely to be required by Contractors . They are

2 .

listed as sources of information for MOD procurement sections and use in navalbases . These documents are only contractual if specifically invoked by theContract.

BR 3001 Marine Engineering Technical InstructionsBR 3018 Technical Organisation and Administration of Nuclear

BR 3321Sub marinesAviation and Motor Transport Fuel System in HM Ships

BR 4000 The Dock BookBR 8581 Management Regulations for HM Naval Bases and other

NES 850Issue 1

ANNEX DFOX 2749/366

34.

ALPHABETICAL INDEX

NES 850Issue 1

Alignment. 0410 .Ammunition . Annex C .

Backhaul wires. 1012.Ballast tanks. 0322, 0525a, 0703g .Bar keels. 0407.Bottoming . 0504 .Bottom Plugs . 0903 .Breakage. 0303 .

Calculations. 0309, 0317a, 1103, 1104 .0317b, 0320,Cradle. 0318b .

Datums. 0324 .Declivity. 0318a .Diaphragm Plates . 0402 .

Distortion. 0321, 0413 .Diver . 0321 .Docking Plans. 0301, 0302, 0320, 0324, 0402, 0416, 0514, 0519, 0809, 1402, 1403 .

Earthing . 0313.

Fixed Domes. 0512, 0606 .Flow of Water . 0506.Fuel tanks . 0322, 0525a, 0703g .

Graving Dock . 0323, 0407, 0808b,Grounding . 0317a, 0318b .GRP Vessels. 0521 .

Hydrostatic curves . 0525c.

0808c, 0812a.

Inspection. 0325, 0604, 0810, 0904, 0905, 1003 .

Kingston Valves . 0530, 0531, 0702, 0703h, 0703o .

FOX 2749/366 35 .

NES 850Issue 1

Lightning Conductors. 0313 .Line of Sight. 0407 .

New construction. 0303 .Nuclear submarines. 0317b .

Pawls. 1011 .Permission. ANNEX A, ANNEX C.Poisons. 0523b.Profiling . 0416 .

Safety. 0525, 0806, 1209 .

Underwater projections. 0316 .

Weights . 0303b, 0309, 0321, 0525a, 0525b, 0528, 1103, 1204, 1205, 1206, 1208, 1212,1305, 1307, 1405, ANNEX A, ANNEX B .

FOX 2749/366

36 .

Services. 0311 .Signs. 0816 .Siphoning. 0321 .Sonar. 0414, 0811 .Stability . 0317a, 0317b,Stability Curves. 0525c .

0525, 0902 .

Stabilized Electrical Power . 0314 .Stabilizer . 0319 .Sue. 0318a, 0402, 0511, 0515, 0516a, 0522, 1010 .

Tidal docks. 0316, 0502 .Toxins. 0523b .

0532, 0703Z, 0902, 1010, 1212 .Trim. 0318, 0323, 0527,

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CO Crown Copyright 2000

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Contract Requirements

When Defence Standards are incorporated into contracts users are responsible for their correctapplication and for complying with contractual and statutory requirements . Compliance witha Defence Standard does not in itself confer immunity from legal obligations .

Revision of Defence Standards

Defence Standards are revised as necessary by up issue or amendment . It is important thatusers of Defence Standards should ascertain that they are in possession of the latest issue oramendment. Information on all Defence Standards is contained in Def Stan 00-00 Standardsfor Defence Part 3 , Index of Standards for Defence Procurement Section 4 `Index of DefenceStandards and Defence Specifications' published annually and supplemented regularly byStandards in Defence News (SID News) . Any person who, when making use of a DefenceStandard encounters an inaccuracy or ambiguity is requested to notify the Directorate ofStandardization (DStan) without delay in order that the matter may be investigated andappropriate action taken .