Post on 24-Oct-2015
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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 with intact 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 “such information satisfactory to the Administration as is necessary to enable him by rapid and simple processes to obtain accurate guidance as to the stability of the ship under varying conditions 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 what is “satisfactory” 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
JURISDICTIONJURISDICTIONDetermined by ship type and trading pattern
– Military – DoD’s own rules but are often guided by commercial rules which they may make mandatory (ref. s.3, Navigation Act 1912)
– Trading ship (ref. s.2(a), Navigation Act) - State requirements (USL Code) for intra-state voyages incl charter 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 (USL Code) unless on international voyages, then AMSA
– Pleasure craft (ref. s.2(d), Navigation Act) - State Boating laws re equipment but refer AYF and relevant parts of AS.1799 re design and construction
DEFINITIONSDEFINITIONSPassenger ship (SOLAS) is ship which carries more
than 12 passengersCargo ship (SOLAS) is any ship which is not a
passenger shipSpecial 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 Offshore Supply Vessel (OSV) Guidelines
– Intact and damage stability requirements Mobile Offshore Drilling Unit (MODU) Code
– Includes intact & damage stability High-Speed Craft Code (2000)
– Alternative to SOLAS construction/equipment /certification requirements, includes intact & damage stability criteria
Special Purpose Ship Code– Modifies SOLAS for SPSs, includes intact & damage
stability criteria Uniform Shipping Laws (USL) Code
– Used by State/NT authorities, stability mainly intact
IMO INTACT STABILITY CODEIMO INTACT STABILITY CODEAdopted 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 by IMO (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
TYPICAL TRIM & STABILITY TYPICAL TRIM & STABILITY BOOKLET AS PER MO.12BOOKLET AS PER MO.12
General stability-related info– vessel particulars, draft mark diagram, immersion angle
& heeling lever diagramsInfo for Master and officers
– Instructions & stability criteriaWorked example of stability condition calculationCalculations for typical / “worst” loading conditionsSupporting data/tables/graphs
– Tank plan & table, tank calibrations, hydrostatic tables, KN tables, nomenclature, inclining report
NOTE – Actual required content varies with ship type
STABILITY CRITERIA –STABILITY CRITERIA –LANDING CRAFT LANDING 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
STABILITY CRITERIA –STABILITY CRITERIA –MBD DAY SAILER/RACER MBD DAY SAILER/RACER
As “pleasure craft” no statutory stability requirements apply– But refer AYF stability requirements(?)
Refer yacht stability requirements(?) of AS.1799 Small Pleasure Boats Code– 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!)
STABILITY CRITERIA –STABILITY CRITERIA –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 Code calls up the “Severe wind and rolling criterion” from the IMO Intact Stability Code– Absence of adjustments to tabulated factors to apply to
HSC renders such application difficult
STABILITY CRITERIA –STABILITY CRITERIA –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 relevant operational information being
included in Trim & Stability Booklet)
ANY QUESTIONS????ANY QUESTIONS????
DAMAGE STABILITYDAMAGE STABILITY – SOLAS & MARPOL – SOLAS & MARPOL
SOLAS Ch. II-1 Part B provides deterministic requirements for subdivision of passenger ships, Res. A.265(VIII) is probabilistic alternative
SOLAS reg.II-1/8-1 covers probabilistic subdivision and damage stability of ro-ro passenger ships
SOLAS Ch.II-1 Part B-1 provides for probabilistic subdivision & damage stability for dry cargo ships of L>80m unless covered by deterministic criteria
MARPOL Annex I specifies oil tanker subdivision & damage stability requirements incl. double-hulls
DAMAGE STABILITY – DAMAGE STABILITY – SOLAS/MARPOL-RELATED CODESSOLAS/MARPOL-RELATED CODES
International Bulk Chemical (IBC) Code gives requirements for chemical carriers– note that where a chemical carrier can carry
petroleum grades in addition to noxious liquid substances in bulk, MARPOL Annex I also applies
International Gas Carrier (IGC) Code gives requirements for liquefied gas carriers
Other Codes cover existing ships – unnecessary to list here
NOTE RE PROBABILISTIC NOTE RE PROBABILISTIC
DAMAGE STABILITYDAMAGE STABILITYRes. 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-1/8-1Amendments to SOLAS Ch. II-1 scheduled for
adoption in May to “harmonise” probabilistic method for passenger & cargo ships (flood length)
Probabilistic principles likely to be extended to Load Line and MARPOL Conventions’ damage stability
MARPOL Annex I oil outflow and guidelines for double-hull equivalence are already probabilistic
INTACT STABILITY DATA -INTACT STABILITY DATA -DAMAGE STABILITY LINKDAMAGE STABILITY LINK
A given ship at a given displacement and trim will have a limiting intact KG at which it meets any damage stability criterion
Tracking this data over a range of intact displacements and trims gives a series of limiting KG curves within which the ship must be operated to maintain compliance with the criterion
Such curves are most useful to the Master when integrated into the intact stability booklet– preferably on the same page as similar limiting KG
information for intact stability criteria
OTHER ASPECTS OF OTHER ASPECTS OF STABILITYSTABILITY
SHIPS FOR DRY BULK SHIPS FOR DRY BULK CARGOESCARGOESThe most important criterion for such ships is in
relation to ships which may carry grain, which must comply with the International Grain Code which is given 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 and coal trades – commercially important in terms of both resale features and being able to accept grain cargoes when they arise
– Involves provision of Grain Stability DataFor specialised bulk cargoes, Bulk Cargoes Code
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 Convention Annex I, Ch. IV provides for assignment of “lumber” load lines– stability requirements are as per 4.1 of Intact
Stability Code which in turn calls up the Code of Safe Practice for Ships Carrying Timber Deck Cargoes
SUMMARYSUMMARYIt 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 intact stability criteria related to cargoes and the operational linkage between intact and damage stability should not be overlooked
ANY QUESTIONS????ANY QUESTIONS????