AMSA_Stability

8/6/2019 AMSA_Stability

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STABILITY REQUIREMENTSSTABILITY REQUIREMENTS

Rob Gehling

Principal Adviser ± Technical Marine Standards

Maritime Safety & Environmental Strategy

AMSA, Canberra



YOUR TASKYOUR TASK

Presumed to be to design your vessel withintact stability characteristics to meet the

appropriate statutory criteria

- and ultimately prepare trim & stability

booklet as would be required for

submission to a regulatory authority



YOUR AIM!YOUR AIM! If under AMSA jurisdiction, to provide the Master

with ³such information satisfactory to theAdministration as is necessary to enable him byrapid and simple processes to obtain accurate

guidance as to the stability of the ship under varyingconditions of service´

± Refer SOLAS II-1/22.1

± Load Lines Protocol (1988) reg. 10(2)(b) similar

Appendix 2 of Marine Orders Part 12 defines whatis ³satisfactory´ to AMSA

Other jurisdictions (eg. State, Military) have similar,

if sometimes less stringent requirements



MY BACKGROUNDMY BACKGROUND

3 years as Naval Architect in Drawing Office of

large shipyard, preparing and gaining approval for

stability booklets

12 years in AMSA and its predecessors, assessing

and approving stability booklets

Australian delegate to IMO¶s Sub-Committee on

Stability, Load Lines and Fishing Vessels Safety(SLF) since 1988, taking specific interest in

operational intact stability issues

± Recently elected as Vice-Chairman of SLF



JURISDICTIONJURISDICTION Determined by ship type and trading pattern

± Military ± DoD¶s own rules but are often guided bycommercial rules which they may make mandatory (ref.s.3, Navigation Act 1912)

± Trading ship (ref. s.2(a), Navigation Act) - Staterequirements (USL Code) for intra-state voyages inclcharter boats, but AMSA (Marine Orders/SOLAS) for inter-state and international service

± Fishing vessel or fishing fleet support vessel (ref.

s.2(b)/(ba), Navigation Act) ± State requirements (USLCode) unless on international voyages, then AMSA

± Pleasure craft (ref. s.2(d), Navigation Act) - StateBoating laws re equipment but refer AYF and relevant parts of AS.1799 re design and construction



DEFINITIONSDEFINITIONS Passenger ship (SOLAS) is ship which carries more

than 12 passengers

C argo ship (SOLAS) is any ship which is not a

passenger ship S pecial purpose ship (Special Purpose Ship Code) is

a mechanically self-propelled ship which by reason

of its function carries more than 12 special

personnel (persons who are not passengers or crew

and who are in board in connection with the special

purpose of the ship or special work being carried out

aboard the ship, number includes any passengers)



CODESCODES Off shore S upply Vessel ( OS V) Guidelines

± Intact and damage stability requirements

M obile Off shore Drilling Unit ( M O DU) C ode

± Includes intact & damage stability

H igh-S peed C ra f t C ode (2000)

± Alternative to SOLAS construction/equipment/certification requirements, includes intact & damagestability criteria

S pecial Purpose S hip C ode ± Modifies SOLAS for SPSs, includes intact & damage

stability criteria

Uni f orm S hipping Laws (U S L) C ode

± Used by State/NT authorities, stability mainly intact



IMO INTACT STABILITY CODEIMO INTACT STABILITY CODE

Adopted in November 1993 through res. A.749(18)and has since been amended by res. MSC.75(69)

Intended to be a consolidation of requirements and

guidance information adopted byIMO (eg. res.A.167(ES.IV), A.168(ES.IV), A.206(VII),

A.268(VIII) & Codes for specific vessel types)

± Non-mandatory but now under review again with view to

some parts being made mandatory

Useful reference but not implemented by Australia

(refer Marine Orders Part 12) because of problems

with weather criterion among other things



BOOKLET AS PER MO.12BOOKLET AS PER MO.12

General stability-related info ± vessel particulars, draft mark diagram, immersion angle

& heeling lever diagrams

Info for Master and officers

± Instructions & stability criteria

Worked example of stability condition calculation

Calculations for typical / ³worst´ loading conditions

Supporting data/tables/graphs

± Tank plan & table, tank calibrations, hydrostatic tables,KN tables, nomenclature, inclining report

NOTE ± Actual required content varies with ship type



STABILITY CRITERIASTABILITY CRITERIA ± ±

LANDING CRAFTLANDING CRAFT Statutory Authority is Dept of Defence, so following

info relates to hypothetical (?) application of

commercial criteria

Criteria are at 6.2.2 and 6.2.3 of Appendix 2 to

Marine Orders Part 12, most likely using 6.2.3(k), or

8.C.16 of USL Code

± Allows for maximum GZ to occur at angles between

15deg. and 25deg, but requires higher area under GZ

curve to 30deg. than normal IMO criteria

± Note that criteria not to vary between load conditions




MBD DAY SAILER/RACERMBD DAY SAILER/RACER

As ³pleasure craft´ no statutory stability requirements apply

± But refer AYF stability requirements(?)

Refer yacht stability requirements(?) of AS.1799 S mall

Pleasure Boats C ode

± Not mandatory but have effect under consumer protection and

trade practices law

Statutory stability requirements could apply if vessel put

into survey for commercial operations (eg. harbour sailing)

± USL Code section 8.C.12 implemented by State authorities and

also called up by Marine Orders Part 12 (not AMSA jurisdiction!)




NWBS DAY TRIP BOATNWBS DAY TRIP BOAT Apply relevant criteria from section 8.C.1 of USL

Code

± Assuming vessel is under State jurisdiction (not AMSA)

Could use criteria of 2.3 to 2.5 of 2000 HSC Code ± Call-up standards of Annexes 7 and 8 of Code,

depending on whether craft is monohull or multihull

Note that 1.1 of Annex 8 to the 2000 HSC Codecalls up the ³Severe wind and rolling criterion´ from

the IMO Intact Stability Code

± Absence of adjustments to tabulated factors to apply to

HSC renders such application difficult




NWBS DAY TRIP BOAT (CONT)NWBS DAY TRIP BOAT (CONT) Note that Table 2.3.4 of 2000 HSC Code provides

for some inter-changeability between the

requirements of Annexes 7 and 8 ± Eg. trimarans¶ stability is similar to monohulls but amahs

of can be tailored to meet the specified stability criteria

CFD may soon enable compliance with 2.4 to be

verified by calculation but trials required for now

Intact stability criteria currently being researched as

major part of review of 2000 HSC Code



AUSTAL MONOHULL AUSTAL MONOHULL

CREW/SUPPLY VESSELCREW/SUPPLY VESSEL Mexican flag and high service speed would

normally pose questions

± But these are answered by specification of IMO Code on

Intact Stability (IS Code)

± Severe Weather Criterion NOT required

Note 2000 HSC Code could not be applied as HSC

Code requires high-speed criterion to be met at

displacement of maximum operational weight

Consider using 4.5.6 of IS Code in place of 3.1.2

± Offshore cargo handling probably precludes fitting

passenger cabin above cargo deck



DAMAGE STABILITYDAMAGE STABILITY

(Not part of brief for this presentation

but generally results in relevantoperational information being

included in Trim & Stability Booklet)



ANY QUESTIONS???? ANY QUESTIONS????



NOTE RE PROBABILISTICNOTE RE PROBABILISTIC

DAMAGE STABILITYDAMAGE STABILITY Res. A.265 (IX) (1973) is probabilistic alternative to

SOLAS Ch.II-1 damage stability requirements

± now applied to ro-ro passenger ships through

SOLAS reg.II

-1/8-1 Amendments to SOLAS Ch. II-1 scheduled for

adoption in May to ³harmonise´ probabilisticmethod for passenger & cargo ships (flood length)

Probabilistic principles likely to be extended to LoadLine and MARPOL Conventions¶ damage stability

MARPOL Annex I oil outflow and guidelines for

double-hull equivalence are already probabilistic



INTACT STABILITY DATAINTACT STABILITY DATA --

DAMAGE STABILITY LINKDAMAGE STABILITY LINK

A given ship at a given displacement and trim willhave a limiting intact KG at which it meets anydamage stability criterion

Tracking this data over a range of intactdisplacements and trims gives a series of limitingKG curves within which the ship must be operatedto maintain compliance with the criterion

Such curves are most useful to the Master whenintegrated into the intact stability booklet

± preferably on the same page as similar limiting KGinformation for intact stability criteria



OTHER ASPECTS OFOTHER ASPECTS OF

STABILITYSTABILITY



CARGOESCARGOES The most important criterion for such ships is in

relation to ships which may carry grain, which mustcomply with the I nternational Grain C ode which isgiven mandatory effect in SOLAS reg. VI/9

± Most bulk carriers are designed to comply with this Code

even if they are intended to engage in the iron ore andcoal trades ± commercially important in terms of bothresale features and being able to accept grain cargoeswhen they arise

± Involves provision of Grain Stability Data For specialised bulk cargoes, Bulk C argoes C ode

should be checked for any extra requirements

± Eg. transportable moisture limits, extra watertight

integrity / bilge requirements, gas sniffing (coal)



TIMBER CARGOESTIMBER CARGOES

Many Handy-size bulk carriers are arranged for

carriage of timber on deck (clear side-decks,

stanchions) 1966 Load Line C onvention Annex I, Ch. IV

provides for assignment of ³lumber´ load lines

± stability requirements are as per 4.1 of I ntact S tability C ode which in turn calls up the C ode o f

S a f e Practice f or S hips C arrying Timber Deck

C argoes



SUMMARYSUMMARY It is essential to establish the jurisdiction and

regulatory environment in which the ship will

operate at the outset

± This varies between your selected projects AMSA intact stability requirements generally build

on basic IMO stability criteria, HSC is exception

Looking beyond intact stability, relevant intactstability criteria related to cargoes and the

operational linkage between intact and damage

stability should not be overlooked



ANY QUESTIONS???? ANY QUESTIONS????

AMSA_Stability

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