4.2 Fishing vessels

 The provisions given hereunder apply to decked seagoing fishing vessels as defined in 1.3.4. The stability criteria given in 4.2.3 and 4.2.4 below should be complied with for all conditions of loading as specified in 4.2.5, unless the Administration is satisfied that operating experience justifies departures therefrom.

 Apart from general precautions referred to in sections 2.3and 2.5, the following measures should be considered as preliminary guidance on matters influencing safety as related to stability.

• .1 all fishing gear and other large weights should be properly stowed and placed as low as possible;

• .2 particular care should be taken when pull from fishing gear might have a bad effect on stability, e.g., when nets are hauled by power-block or the trawl catches obstructions on the sea-bed;

• .3 gear for releasing deck load in fishing vessels carrying catch on deck, e.g., herring, should be kept in good working condition for use when necessary;

• .4 when the main deck is prepared for the carriage of deck load by division with pound boards, there should be slots between them of suitable size to allow easy flow of water to freeing ports to prevent trapping of water;

• .5 fish should never be carried in bulk without first being sure that the portable divisions in the holds are properly installed;

• .6 reliance on automatic steering may be dangerous as this prevents changes to course which may be needed in bad weather;

• .7 in all conditions of loading necessary care should be taken to maintain a seaworthy freeboard.

• .8 particular care should be taken when the pull from fishing gear results in dangerous heel angles. This may occur when fishing gear fastens onto an underwater obstacle or when handling fishing gear, particularly on purse seiners, or when one of the trawl wires tears off. The heel angles caused by the fishing gear in these situations may be eliminated by employing devices which can relieve or remove excessive forces applied through the fishing gear. Such devices should not impose a danger to the vessel through operating in circumstances other than those for which they were intended.

  4.2.3.1 The general intact stability criteria given in section 3.1.2 (paragraphs 3.1.2.1 to 3.1.2.3) should it apply to fishing vessels having a length of 24 m and over, with the exception of requirements on the initial metacentric height GM_o (paragraph 3.1.2.4) which, for fishing vessels, should not be less than 0.35 m for single deck vessels. In vessels with complete superstructure or vessels of 70 m in length and over the metacentric height may be reduced to the satisfaction of the Administration but in no case should be less than 0.15 m.

  4.2.3.2 The adoption by individual countries of simplified criteria which apply such basic stability values to their own types and classes of vessels is recognized as a practical and valuable method of economically judging the stability.

  4.2.3.3 Where arrangements other than bilge keels are provided to limit the angle of roll, the Administration should be satisfied that the stability criteria referred to in 4.2.3.1 are maintained in all operating conditions.

  4.2.4.1 The Administration may apply the provisions of 3.2 to fishing vessels of 45 m length and over.

  4.2.4.2 For fishing vessels in the length range between 24 m and 45 m, the Administration may apply the provisions of 3.2. Alternatively the values of wind pressure (see 3.2.2.2) may be taken from the following table:

 where h is the vertical distance from the centre of the projected vertical area of the vessel above the waterline, to the waterline.

  4.2.5.1 The standard loading conditions referred to in 4.2.1 are as follows:

• .1 departure conditions for the fishing grounds with full fuel, stores, ice, fishing gear, etc;

• .2 departure from the fishing grounds with full catch and a percentage of stores, fuel, etc., as agreed by the Administration;

• .3 arrival at home port with 10% stores, fuel, etc., remaining and full catch;

• .4 arrival at home port with 10% stores, fuel, etc., and a minimum catch, which should normally be 20% of full catch but may be up to 40% provided the Administration is satisfied that operating patterns justify such a value.

  4.2.5.2 Assumptions for calculating loading conditions should be as follows:

• .1 allowance should be made for the weight of the wet fishing nets and tackle, etc., on deck;

• .2 allowance for icing, where this is anticipated to occur should be made in accordance with the provisions of section 5.3;

• .3 in all cases the cargo should be assumed to be homogenous unless this is inconsistent with practice;

• .4 in conditions referred to in 4.2.5.1.2 and 4.2.5.1.3 deck cargo should be included if such a practice is anticipated;

• .5 water ballast should normally only be included if carried in tanks which are specially provided for this purpose.

  4.2.6.1 For decked vessels with a length less than 30 m, the following approximate formula for the minimum metacentric height GM_min (in metres) for all operating conditions should be used as the criterion:

The formula is applicable for vessels having:

• .1 f/B between 0.02 and 0.20;

• .2 l_s/L smaller than 0.60;

• .3 B/D between 1.75 and 2.15;

• .4 sheer fore and aft at least equal to or exceeding the standard sheer prescribed in regulation 38(8) of the International Convention on Load Lines, 1966;

• .5 height of superstructure included in the calculation not less than 1.8 m.

For ships with parameters outside of the above limits the formula should be applied with special care.

  4.2.6.2 The above formula is not intended as a replacement for the basic criteria given in 4.2.3 and 4.2.4 but is to be used only if circumstances are such that cross curves of stability, KM curve and subsequent GZ curves are not and cannot be made available for judging a particular vessel's stability.

  4.2.6.3 The calculated value of GM_min should be compared with actual GM values of the vessel in all loading conditions. If a rolling test (see section 7.6), an inclining experiment based on estimated displacement or another approximate method of determining the actual GM is used, a safety margin should be added to the calculated GM_min.