Page 361 - Ship Construction.DJ Eyres 6Ed

Ch31-H8070.fm Page 350 Wednesday, October 18, 2006 7:06 AM
350 Ship Construction
is always accessible. Where the distance exceeds 0.02L a single automatic
non-return valve without positive means of closing may be accepted. In
manned machinery spaces, main and auxiliary sea inlets and discharges in
connection with the operation of machinery may be controlled locally. Scup-
pers and discharge pipes originating at any level and penetrating the shell
either more than 450 mm below the freeboard deck or less than 600 mm
above the summer water-line should be fitted with an automatic non-return
--- ใช้เพื่อการศึกษาเท่านั้น---
valve. Scuppers leading from superstructures or deckhouses not fitted with
weathertight doors should be led overboard.
งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
(11) Side Scuttles Below the freeboard deck or within the enclosed super-
structures side scuttles should be fitted with efficient hinged, water-tight,
inside deadlights. No side scuttle should be fitted with its sill below a line
drawn parallel to the freeboard deck at side and having its lowest point 2.5
per cent of the ship’s breadth above the summer water-line or 500 mm
whichever is the greater distance.

(12) Freeing Ports The minimum freeing port area (A) on each side of the
ship where sheer in way of the well is standard or greater than standard, is
given, in square metres, by:
ึ
A = 0.7 + 0.035l where l is the length of bulwark in the well and is
less than 20 m
and A =0.07l where l is greater than 20 m.

In no case need l be greater than 0.7L. If the bulwark is greater than
1.2 m in height A is increased by 0.004 sq. m/m of length of well for each
0.1 m difference in height. If the bulwark is less than 0.9 m in height, A is
reduced by 0.004 sq.m/m of length of well for each 0.1 m difference in
height. Where there is no sheer A is increased by 50 per cent and with less
than standard sheer the per cent increase is obtained by interpolation.
The lower edges of freeing ports should be as near the deck as practicable.
Two-thirds of the freeing port area is required to be provided in the half of
the well nearest the lowest point of the sheer curve, where the deck has sheer.
Openings in the bulwarks are protected by bars spaced approximately
230mm apart. If shutters are fitted, these should be prevented from jamming.

(13) Protection of Crew Efficient guard-rails or bulwarks of minimum
height 1 metre are to be fitted on all exposed parts of freeboard and super-
structure decks. A lower rail may be permitted by the Administration. The
maximum vertical spacing between deck and lower rail is 230 mm, and
between other rails is 380 mm.
Satisfactory means should be provided for protection of crew in getting
to and from their quarters and other parts used in the working of the ship.