7.8.1 Where bulwarks on the weather portion of
the freeboard or superstructure decks or, in fishing vessels, the
working decks form wells, freeing ports should be arranged along the
length of the bulwark as to ensure that the deck is freed of water
most rapidly and effectively. Lower edges of freeing ports should
be as near the deck as practicable.footnote
7.8.2 In ships to which the International Convention
on Load Lines, 1966 or the Protocol of 1988 relating thereto as amended,
as applicable, applies, freeing ports should comply with regulation 24 of this Convention.
7.8.3 In decked fishing vessels of 12 m in length
and over, freeing ports should comply with the followingfootnote.
7.8.3.1 The minimum freeing port area A in
m2, on each side of the vessel for each well on the working
deck, should be determined in relation to the length l and
height of bulwark in the well as follows:
-
.1
A = K*l
where:
-
K =
0.07 for vessels of 24 m in length
and over
-
K =
0.035 for vessels of 12 m in
length; for intermediate lengths the value of K should
be obtained by linear interpolation (l need not be taken
as greater than 70% of the vessel's length);
-
.2 where the bulwark is more than 1.2 m in average
height, the required area should be increased by 0.004 m² per
metre of length of well for each 0.1 m difference in height; and
-
.3 where the bulwark is less than 0.9 m in average
height, the required area may be decreased by 0.004 m² per metre
of length of well for each 0.1 m difference in height.
7.8.3.2 The freeing port area calculated according
to 7.8.3.1 should be increased where the Administration or competent
authority considers that the vessel's sheer is not sufficient to ensure
rapid and effective freeing of the deck of water.
7.8.3.3 Subject to the approval of the Administration
or competent authority, the minimum freeing port area for each well
on the superstructure deck should be not less than one-half the area A given in 7.8.3.1 except that where the superstructure deck
forms a working deck for fishing operations the minimum area on each
side should be not less than 75% of the area A.
7.8.3.4 Freeing ports should be so arranged along
the length of bulwarks as to provide the most rapid and effective
freeing of the deck from water. Lower edges of freeing ports should
be as near the deck as practicable.
7.8.3.5 Pound boards and means for stowage and
working the fishing gear should be arranged so that the effectiveness
of the freeing ports will not be impaired or water trapped on deck
and prevented from easily reaching the freeing ports. Pound boards
should be so constructed that they can be locked in position when
in use and will not hamper the discharge of shipped water.
7.8.3.6 Freeing ports over 0.3 m in depth should
be fitted with bars spaced not more than 0.23 m nor less than 0.15
m apart or provided with other suitable protective arrangements. Freeing
port covers, if fitted, should be of approved construction. If devices
are considered necessary for locking freeing port covers during fishing
operations they should be to the satisfaction of the competent authority
and easily operable from a readily accessible position.
7.8.3.7 In vessels intended to operate in areas
subject to icing, covers and protective arrangements for freeing ports
should be capable of being easily removed to restrict ice accumulation.
Size of opening and means provided for removal of these protective
arrangements should be to the satisfaction of the competent authority.
7.8.3.8 In addition, in fishing vessels of 12
m in length and above but less than 24 m in length where wells or
cockpits are fitted in the working deck or superstructure deck with
their bottoms above the deepest operating waterline, efficient non-return
means of drainage overboard should be provided. Where bottoms of such
wells or cockpits are below the deepest operating waterline, drainage
to the bilges should be provided.
7.8.4 In offshore supply vessels, the Administration
should give special attention to adequate drainage of pipe stowage
positions, having regard to the individual characteristics of the
vessel. However, the area provided for drainage of the pipe stowage
positions should be in excess of the required freeing port area in
the cargo deck bulwark and should not be fitted with shutters.