The document outlines standard specifications for the construction and stability of local fishing vessels under 24 meters in length. Key criteria include adequate stability for service conditions, buoyancy requirements, and methods for determining stability through rolling period tests. The regulations also define tests, calculations, and the responsibilities of authorities regarding vessel stability and construction.

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Standard Specifications for the Construction of a Local
Fishing Vessel of less than 24 Metres in Length Overall
Country …………
Act…...................
Regulation ……..
Section………….
Schedule 6 Stability and associated seaworthiness

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Contents
1 Stability and associated sea worthiness .................................................................1
1.1 General...............................................................................................................1
1.1.1 A local fishing vessel shall be so designed and constructed to provide
adequate intact stability for the anticipated service conditions. ............................1
1.1.2 Wherever practicable, guidance shall be provided for an approximate
determination of the vessel’s stability by means of the rolling period test
including values of rolling coefficients particular to the vessel ............................1
1.1.3 The freeboard of a decked fishing vessel at the maximum foreseeable
operating displacement shall be:............................................................................1
1.2 Stability criteria..................................................................................................1
1.2.1 The stability of a local decked fishing vessel shall be examined on the
basis of the following criteria: ...............................................................................1
1.2.2 An approximate determination of the righting moment characteristics
may be accepted by the Minister or delegated authority if satisfied that it is
reasonable to employ a particular method to the type of vessel being examined..1
1.2.3 Vessels shall be able to withstand, to the satisfaction of the Minister or
delegated authority, the effect of water on deck, taking account of the seasonal
weather conditions, the sea states in which the vessel will operate, the type of
vessel and its ..........................................................................................................1
1.2.3 mode of operation. .....................................................................................2
1.2.4 The number and type of operating conditions to be considered shall be to
the satisfaction of the Minister or delegated authority and shall include the
following as appropriate: .......................................................................................2
1.2.5 In addition to the specific operating conditions given in 1.2.4, the
Minister or delegated authority shall also be satisfied, that the minimum stability
criteria given in 1.2.1 are met under all other actual operating conditions
including, those which produce the lowest values of the stability parameters
contained in these criteria. .....................................................................................2
1.2.6 Every decked vessel of 12 m in length overall and above shall undergo an
inclining test upon its completion and the actual displacement and position of the
centre of gravity shall be determined for the light ship condition.........................2
1.2.7 Where alterations are made to a decked fishing vessel affecting its light
ship condition and the position of the centre of gravity, the vessel may be re-
inclined, if the Minister or delegated authority considers this necessary and the
stability information revised. .................................................................................2
1.2.8 The inclining test of an individual decked fishing vessel may be omitted
if basic stability data are available from the inclining test of a sister vessel and
that it is demonstrated to the satisfaction of the Minister or the delegated
authority, that reliable stability information for the vessel can be obtained from
such basic data. ......................................................................................................2

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1.2.9 Suitable stability information, to the satisfaction of the Minister or
delegated authority, shall be supplied to enable the skipper to assess with ease
and certainty the stability of the vessel under various operating conditions. Such
information may include specific instructions to the skipper warning him of
those operating conditions that could adversely affect either the stability or the
trim of the vessel....................................................................................................2
1.2.10 Where alterations are made to a vessel affecting its stability, revised
stability calculations shall be undertaken to the satisfaction of the Minister or
delegated authority and the stability information for the skipper shall be revised.2
1.3 Buoyancy ...........................................................................................................2
1.3.1 The Minister or delegated authority may require a wooden fishing vessel
without a deck to be fitted with buoyancy chambers to assist floatation in the
event of flooding....................................................................................................2
1.3.2 The Minister or delegated authority shall require all fibreglass fishing
boats of open construction to be fitted with sealed buoyancy chambers of
sufficient volume that the vessel when fully flooded with all normal crew,
fishing gear and engine(s) aboard will remain afloat. The means of testing for
adequate buoyancy shall be in accordance with the provisions of Schedule 8......2
2 Approximate determination of stability by means of the rolling period tests........3
2.1 Formula..............................................................................................................3
2.1.1 The Minister or delegated authority may use the following formula
extracted from Appendix IV of the Annex to Assembly Resolution A.1681
(ES.IV) of the International Maritime Organization, to make an approximate
determination of stability by means of the rolling period test. ..............................3
2.1.2 The factor "f" is of the greatest importance and for unloaded fishing boats
(but with fuel, stores and equipment). The Minister or delegated authority may
determine more exactly the “f” value(s) for each vessel or class of vessels, as and
when an inclining experiment is carried out in parallel with a rolling test............3
2.1.3 The Minister or delegated authority may use the values for “f”given in
Table 1. ..................................................................................................................3
Table 1 ...........................................................................................................3
2.1.4 The rolling test shall not be taken in a seaway. .........................................3
2.1.5 The formula given above in paragraph 2.1.1 can be reduced to GMo = F
÷ Tr2 provided that the Minister or delegated authority has determined the
value of “F” for the vessel. ....................................................................................3
2.1.6 The calculated value of GMo shall not be less than the critical value set
by the Minister or delegated authority...................................................................3
2.1.7 The initial stability may also be determined graphically by using one of
the attached tables 1 (metric) and 2 (Feet) for feet and/or metric units as
described below: ....................................................................................................3
2.2 Table1 ................................................................................................................5
2.3 Table2 ................................................................................................................6
List of Schedules............................................................................................7

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1 Stability and associated sea worthiness
1.1 General
1.1.1 A local fishing vessel shall be so designed and constructed to provide adequate intact
stability for the anticipated service conditions.
1.1.2 Wherever practicable, guidance shall be provided for an approximate determination
of the vessel’s stability by means of the rolling period test including values of rolling
coefficients particular to the vessel
1.1.3 The freeboard of a decked fishing vessel at the maximum foreseeable operating
displacement shall be:
 compatible with the stability criteria set out in section 2 of this schedule;
 provide a reasonable degree of safety for crew working on deck or in exposed
areas;
 ensure a reasonable degree of safety for the vessel to prevent entry of water into
enclosed spaces having regard to the closing appliances provided and to the
influence of water being shipped and trapped on deck
1.2 Stability criteria
1.2.1 The stability of a local decked fishing vessel shall be examined on the basis of the
following criteria:
 that the area under the righting lever curve (GZ curve) shall not be less than 0.055
m-radians up to 30° angle of heel and not less than 0.090 m-radians up to 40° or
the angle of flooding f if this angle is less than 40°. Additionally, the area under
the righting lever curve (GZ curve), between the angles of heel of 30° and 40° or
between 30° and f, if this angle is less than 40°, shall not be less than 0.030 m-
radians. f is the angle of heel at which openings in the hull, superstructures or
deckhouses which cannot rapidly be closed watertight commence to immerse. In
applying this criterion, small openings through which progressive flooding cannot
take place need not be considered as open;
 the righting lever GZ shall be at least 200 mm at an angle of heel equal to or
greater than 30° and the maximum righting lever GZmax should occur at an angle
of heel preferably exceeding 30° but not less than 25°; and
 the initial metacentric height GM0 shall not be less than 350 mm for single deck
vessels. In vessels with complete superstructure, the metacentric height may be
reduced to the satisfaction of the Minister or delegated authority but in no case
shall it be less than 150 mm.
1.2.2 An approximate determination of the righting moment characteristics may be
accepted by the Minister or delegated authority if satisfied that it is reasonable to
employ a particular method to the type of vessel being examined.
1.2.3 Vessels shall be able to withstand, to the satisfaction of the Minister or delegated
authority, the effect of water on deck, taking account of the seasonal weather
conditions, the sea states in which the vessel will operate, the type of vessel and its

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mode of operation.
1.2.4 The number and type of operating conditions to be considered shall be to the
satisfaction of the Minister or delegated authority and shall include the following as
appropriate:
 departure for the fishing grounds with full fuel, stores, ice, fishing gear, etc.;
 departure from the fishing grounds with full catch;
 arrival at home port with full catch and 10% stores, fuel, etc.; and
 arrival at home port with 10% stores, fuel, etc. and a minimum catch, which
shall normally be 20% of full catch but may be up to 40% provided the competent
authority is satisfied that operating patterns justify such a value.
1.2.5 In addition to the specific operating conditions given in 1.2.4, the Minister or
delegated authority shall also be satisfied, that the minimum stability criteria given in
1.2.1 are met under all other actual operating conditions including, those which
produce the lowest values of the stability parameters contained in these criteria.
1.2.6 Every decked vessel of 12 m in length overall and above shall undergo an inclining
test upon its completion and the actual displacement and position of the centre of
gravity shall be determined for the light ship condition.
1.2.7 Where alterations are made to a decked fishing vessel affecting its light ship
condition and the position of the centre of gravity, the vessel may be re-inclined, if
the Minister or delegated authority considers this necessary and the stability
information revised.
1.2.8 The inclining test of an individual decked fishing vessel may be omitted if basic
stability data are available from the inclining test of a sister vessel and that it is
demonstrated to the satisfaction of the Minister or the delegated authority, that
reliable stability information for the vessel can be obtained from such basic data.
1.2.9 Suitable stability information, to the satisfaction of the Minister or delegated
authority, shall be supplied to enable the skipper to assess with ease and certainty the
stability of the vessel under various operating conditions. Such information may
include specific instructions to the skipper warning him of those operating conditions
that could adversely affect either the stability or the trim of the vessel.
1.2.10 Where alterations are made to a vessel affecting its stability, revised stability
calculations shall be undertaken to the satisfaction of the Minister or delegated
authority and the stability information for the skipper shall be revised.
1.3 Buoyancy
1.3.1 The Minister or delegated authority may require a wooden fishing vessel without a
deck to be fitted with buoyancy chambers to assist floatation in the event of flooding.
1.3.2 The Minister or delegated authority shall require all fibreglass fishing boats of open
construction to be fitted with sealed buoyancy chambers of sufficient volume that the
vessel when fully flooded with all normal crew, fishing gear and engine(s) aboard
will remain afloat. The means of testing for adequate buoyancy shall be in accordance
with the provisions of Schedule 8.

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2 Approximate determination of stability by means of the rolling
period tests
2.1 Formula
2.1.1 The Minister or delegated authority may use the following formula extracted from
Appendix IV of the Annex to Assembly Resolution A.1681 (ES.IV) of the
International Maritime Organization, to make an approximate determination of
stability by means of the rolling period test.
GM0 = (f x B ÷ Tr.) 2
where:
f = factor for the rolling period (different for feet and metric system),
B = breadth of the ship in feet or metric units,
Tr = time for a full rolling period in seconds
(I.e. for one oscillation "to and from" port-starboard-port, or vice versa).
2.1.2 The factor "f" is of the greatest importance and for unloaded fishing boats (but with
fuel, stores and equipment). The Minister or delegated authority may determine more
exactly the “f” value(s) for each vessel or class of vessels, as and when an inclining
experiment is carried out in parallel with a rolling test.
2.1.3 The Minister or delegated authority may use the values for “f”given in Table 1.
Table 1
Type Metric System Feet System
double boom shrimp fishing boats f - 0.95 f -0.555
deep sea fishing boats f - 0.80 f -0.445
boats with a live fish well f -0.60 f - 0.335
2.1.4 The rolling test shall not be taken in a seaway.
2.1.5 The formula given above in paragraph 2.1.1 can be reduced to GMo = F ÷ Tr2
provided that the Minister or delegated authority has determined the value of “F” for
the vessel.
2.1.6 The calculated value of GMo shall not be less than the critical value set by the
Minister or delegated authority.
2.1.7 The initial stability may also be determined graphically by using one of the attached
tables 1 (metric) and 2 (Feet) for feet and/or metric units as described below:
 The values for B and f are marked in the relevant scales and connected by a
straight-line (1). This straight line intersects the vertical line (mm) in the point
(M).

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 A second straight line (2) which connects this point (M) and the point on the Tr
scale corresponding with the determined rolling period, intersects the GM scale at
the requested value.

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2.2 Table1

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2.3 Table2

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List of Schedules
Schedule 1 Prescribed Forms
Schedule 2 Prescribed Fees
Schedule 3 Safety Equipment for a Local Fishing Vessel
Schedule 4 Fire Protection, Fire Detection, Fire Extinguishing and Fire Fighting
Equipment.
Schedule 5 Equipment/Ground Tackle/Anchors and Chains
Schedule 6 Stability and Associated Seaworthiness
Schedule 7 Scantlings for the Construction of a Wooden Hulled Local Fishing Vessel
Schedule 8 Scantlings for the Construction of a Fibreglass Hulled Local Fishing Vessel
Schedule 9 Scantlings for the Construction of a Steel Hulled Local Fishing Vessel
Schedule 10 Machinery and Electrical Installations
Schedule 11 Specifications for the Marking of Fishing Vessels