CONTENTS

INTRODUCTION 76

1. Purpose 76

2. Definition 76

PART A MANDATORY CRITERIA 79

Chapter 1 General 79

1.1 Application 79

Chapter 2 General Criteria 80

2.1 General 80

2.2 Criteria regarding righting lever curve properties 80

2.3 Severe wind and rolling criterion(weather criterion) 80

Chapter 3 Special Criteria for Certain Types of Ships 84

3.1 Passenger ships 84

3.2 Oil tankers of 5,000and above ···········································································

84

3.3 Cargo ships carrying timber deck cargoes 84

3.4 Cargo ships carrying grain in bulk 85

PART B RECOMMENDATIONS FOR CERTAIN TYPES OF SHIPS

AND ADDITIONAL GUIDELINES 86

Chapter 1 General 86

1.1 Purpose 86

1.2 Application 86

Chapter 2 Recommended design criteria for certain Types of Ships 87

2.1 Fishing vessels 87

2.2 Pontoons 88

2.3 Containerships greater than 100 in length 89

2.4 Offshore supply vessels 91

2.5 Special purpose ships 91

2.6 Mobile offshore drilling units(MODUs) 91

Chapter 3 Guidance in Preparing Stability Information 92

3.1 Effect of free surfaces of liquids in tanks 92

3.2 Permanent ballast 93

3.3 Assessment of compliance with stability criteria 93

3.4 Standard conditions of loading to be examined 93

3.5 Calculation of stability curves 95

3.6 Stability booklet 96

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INTRODUCTION

1. Purpose

1.1The purpose of the Guidance is to present mandatory and recommendatory stability criteria and other measures for ensuring the safe operation of ships, to minimize the risk to such ships, to the personnel on board and to the environment. This INTRODUCTION and Pt A of the Guidance ad- dress the mandatory criteria and Pt B contains recommendations and additional guidelines.

1.2This Guidance contains intact stability criteria for the following types of ships and other marine vehicles of 24 in length and above, unless otherwise stated:

.1 cargo ships;

.2 cargo ships carrying timber deck cargoes;

.3 passenger ships;

.4 fishing vessels;

.5 special purpose ships;

.6 offshore supply vessels;

.7 mobile offshore drilling units;

.8 pontoons; and

.9 cargo ships carrying containers on deck and containerships.

1.3 Administrations may impose additional requirements regarding the design aspects of ships of novel design or ships not otherwise covered by the Guidance.

2. Definitions

For the purpose of this Guidance the definitions given hereunder shall apply. For terms used, but not defined in this Guidance, the definitions as given in the 1974 SOLAS Convention, as amended, shall apply.

2.1Administration means the Government of the State whose flag the ship is entitled to fly.

2.2Passenger ship is a ship which carries more than twelve passengers as defined in regulation I/2 of the 1974 SOLAS Convention, as amended.

2.3Cargo ship is any ship which is not a passenger ship, a ship of war and troopship, a ship which is not propelled by mechanical means, a wooden ship of primitive build, a fishing vessel or a mo- bile offshore drilling unit.

2.4Oil tanker means a ship constructed or adapted primarily to carry oil in bulk in its cargo spaces and includes combination carriers and any chemical tanker as defined in Annex II of the MARPOL Convention when it is carrying a cargo or part cargo of oil in bulk.

2.4.1

2.4.2

2.4.3

Combination carrier means a ship designed to carry either oil or solid cargoes in bulk. Crude oil tanker means an oil tanker engaged in the trade of carrying crude oil.

Product carrier means an oil tanker engaged in the trade of carrying oil other than crude oil.

2.5Fishing vessel is a vessel used for catching fish, whales, seals, walrus or other living resources of the sea.

2.6Special purpose ship has the same definition as in the Code of Safety for Special Purpose Ships, 2008(IMO Res.MSC.266(84)).

2.7Offshore supply vessel means a vessel which is engaged primarily in the transport of stores, mate- rials and equipment to offshore installations and designed with accommodation and bridge erections in the forward part of the vessel and an exposed cargo deck in the after part for the handling of cargo at sea.

2.8Mobile offshore drilling unit(MODU or unit) is a ship capable of engaging in drilling operations for the exploration or exploitation of resources beneath the sea-bed such as liquid or gaseous hy- drocarbons, sulphur or salt.

2.8.1 Column-stabilized unit is a unit with the main deck connected to the underwater hull or foot- ings by columns or caissons.

2.8.2 Surface unit is a unit construction intended for

with a ship- or barge-type displacement hull of single or multiple hull operation in the floating condition.

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2.8.3 Self-elevating unit is a unit with moveable legs capable of raising its hull above the surface of the sea.

2.8.4 Coastal State means the Government of the State exercising administrative control over the

drilling operations of the unit.

2.8.5 Mode of operation means a condition or manner in which a unit may operate or function while on location or in transit. The modes of operation of a unit include the following:

.1 operating conditions means conditions wherein a unit is on location for the purpose of con- ducting drilling operations, and combined environmental and operational loadings are within

the appropriate design limits established for such operations. The unit may or supported on the sea-bed, as applicable;

.2 severe storm conditions means conditions wherein a unit may be subjected to

environmental loadings for which the unit is designed. Drilling operations

be either afloat

the most severe are assumed to

have been discontinued due to the severity of the environmental loadings, the unit may be either afloat or supported on the sea-bed, as applicable; and

.3 transit conditions means conditions wherein a unit is moving from one geographical location

to another.

2.9 High-speed craft(HSC)* is a craft capable of a maximum speed, in metres per second( ), equal to or exceeding:

* : The Code of Safety for High-Speed Craft, 2000(2000 HSC Code) has been developed following a thorough revision of the Code of Safety for High-Speed Craft, 1994(1994 HSC Code) which was derived from the previous Code of Safety for Dynamically Supported Craft(DSC Code) adopted by IMO in 1977, recognizing that safety levels can be significantly enhanced by the infrastructure associated with regular service on a particular route, whereas the conventional ship safety philosophy relies on the ship being self-sustaining with all necessary emergency equipment being carried on board.

∇

where:

∇ = volume of displacement corresponding to the design waterline ( ).

2.10 Containership means a ship which is used primarily for the transport of marine containers.

2.11 Freeboard is the distance between the assigned load line and freeboard deck**.

** : For the purposes of application of chapters I and II of Annex I of the International Convention on Load Lines, 1966 or the Protocol of 1988 as amended, as applicable to open- top containerships, "freeboard deck" is the freeboard deck according to the International Convention on Load Lines, 1966 or the Protocol of 1988 as amended, as applicable as if hatch covers are fitted on top of the hatch cargo coamings.

2.12 Length of ship

The length should be taken as 96% of the total length on a waterline at 85% of the least moulded depth measured from the top of the keel, or as the length from the fore side of the stem to the axis of the rudder stock on the waterline, if that be greater. In ships designed with a rake of keel the waterline on which this length is measured should be parallel to the designed waterline.

2.13 Moulded breadth is the maximum breadth of the ship measured amidships to the moulded line of the frame in a ship with a metal shell and to the outer surface of the hull in a ship with a shell of any other material.

2.14 Moulded depth is the vertical distance measured from the top of the keel to the top of the free- board deck beam at side. In wood and composite ships, the distance is measured from the lower edge of the keel rabbet. Where the form at the lower part of the midship section is of a hollow

character, or where thick garboards are

fitted, the distance is measured from the point where the

line of the flat of the bottom continued inwards cuts the side of the keel. In ships having rounded

gunwales, the moulded depth should be

measured to the point of intersection of the moulded lines

of the deck and side shell plating, the lines extending as though the gunwale were of angular

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design. Where the freeboard deck is stepped and the raised part of the deck extends over the point at which the moulded depth is to be determined, the moulded depth should be measured to a line of reference extending from the lower part of the deck along a line parallel with the raised part.

2.15 Near-coastal voyage means a voyage in the vicinity of the coast of a State as defined by the Administration of that State.

2.16 Pontoon is considered to be normally:

.1 non self-propelled;

.2 unmanned;

.3 carrying only deck cargo;

.4 having a block coefficient of 0.9 or greater;

.5 having a breadth/depth ratio of greater than 3; and

.6 having no hatchways in the deck except small manholes closed with gasketed covers.

2.17 Timber means sawn wood or lumber, cants, logs, poles, pulpwood and all other types of timber in loose or packaged forms. The term does not include wood pulp or similar cargo.

2.18 Timber deck cargo means a cargo of timber carried on an uncovered part of a freeboard or su- perstructure deck. The term does not include wood pulp or similar cargo.*

* : Refer to regulation 42(1) of the International Convention on Load Lines, 1966 or the Protocol of 1988 as amended, as applicable.

2.19 Timber load line means a special load line assigned to ships complying with certain conditions related to their construction set out in the International Convention on Load Lines and used when the cargo complies with the stowage and securing conditions of the Code of Safe Practice for Ships Carrying Timber Deck Cargoes, 1991(IMO Res.A.715(17)).

2.20 Certification of the inclining test weights is the verification of the weight marked on a test weight. Test weights should be certified using a certificated scale. The weighing should be per- formed close enough in time to the inclining test to ensure the measured weight is accurate.

2.21 Draught is the vertical distance from the moulded baseline to the waterline.

2.22 The inclining test involves moving a series of known weights, normally in the transverse direc- tion, and then measuring the resulting change in the equilibrium heel angle of the ship. By using this information and applying basic naval architecture principles, the ship's vertical centre of grav- ity( ) is determined.

2.23 Lightship condition is a ship complete in all respects, but without consumables, stores, cargo, crew and effects, and without any liquids on board except that machinery and piping fluids, such as lubricants and hydraulics, are at operating levels.

2.24 A lightweight survey involves taking an audit of all items which should be added, deducted or relocated on the ship at the time of the inclining test so that the observed condition of the ship can be adjusted to the lightship condition. The mass, longitudinal, transverse and vertical location of each item should be accurately determined and recorded. Using this information, the static water- line of the ship at the time of the inclining test as determined from measuring the freeboard or verified draught marks of the ship, the ship's hydrostatic data, and the sea water density, the light- ship displacement and longitudinal centre of gravity( ) can be obtained. The transverse centre of gravity( ) may also be determined for mobile offshore drilling units(MODUs) and other ships which are asymmetrical about the centreline or whose internal arrangement or outfitting is such that an inherent list may develop from off-centre mass.

2.25 An in-service inclining test means an inclining test which is performed in order to verify the pre- calculated and the deadweight's centre of gravity of an actual loading condition.

2.26 stability instrument is an instrument installed on board a particular ship by means of which it can be ascertained that stability requirements specified for the ship in the Stability Booklet are met in any operational loading condition. A Stability Instrument comprises hardware and software.

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