STABILITY REQUIREMENTS

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STABILITY REQUIREMENTS

• Rob Gehling
• Principal Adviser Technical Marine Standards
• Maritime Safety Environmental Strategy
• AMSA, Canberra

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YOUR 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

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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

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MY 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 IMOs 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

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JURISDICTION

• Determined by ship type and trading pattern
• Military DoDs 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

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DEFINITIONS

• Passenger ship (SOLAS) is ship which carries more
  than 12 passengers
• Cargo ship (SOLAS) is any ship which is not a
  passenger ship
• Special 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)

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CODES

• 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

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IMO 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 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

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TYPICAL TRIM STABILITY BOOKLET 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 / worst 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

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STABILITY CRITERIA 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

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STABILITY CRITERIA 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!)

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STABILITY CRITERIA NWBS 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

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STABILITY CRITERIA 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

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AUSTAL MONOHULL CREW/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

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DAMAGE STABILITY

• (Not part of brief for this presentation but
  generally results in relevant operational
  information being included in Trim Stability
  Booklet)

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ANY QUESTIONS????
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DAMAGE STABILITY 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 Lgt80m unless covered by deterministic
  criteria
• MARPOL Annex I specifies oil tanker subdivision
  damage stability requirements incl. double-hulls

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DAMAGE STABILITY SOLAS/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

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NOTE RE PROBABILISTIC DAMAGE 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 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

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INTACT STABILITY DATA -DAMAGE 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

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OTHER ASPECTS OF STABILITY
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SHIPS FOR DRY BULK CARGOES

• The 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 Data
• For 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)

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TIMBER 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

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SUMMARY

• 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 intact
  stability criteria related to cargoes and the
  operational linkage between intact and damage
  stability should not be overlooked

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ANY QUESTIONS????