✨ Marine Safety Regulations
3260
THE NEW ZEALAND GAZETTE.
[No. 77
Effective Length of Enclosed Superstructures with Middle Line Openings.
Rule LII.—Enclosed Superstructure with Middle Line Openings in the Deck not Provided with Permanent Means of Closing.
Where there is an enclosed superstructure with one or more middle line openings in the deck not provided with permanent means of closing (see Rules VIII to XVI), the effective length of the superstructure is determined as follows:—
(1) Where efficient temporary closing appliances are not provided for the middle line deck openings (see Rule XLV), or the breadth of opening is 80 per cent. or more of the Breadth B₁ of superstructure deck at the middle of the opening, the ship is considered as having an open well in way of each opening, and freeing ports are to be provided in way of this well. The effective length of superstructure between openings is governed by Rules XLVII, XLIX, and L.
(2) Where efficient temporary closing appliances are provided for middle line deck openings and the breadth of opening is less than 0·8 B₁, the effective length is governed by Rules XLVII, XLIX, and L, except that where access openings in ’tween deck bulkheads are closed by Class 2 closing appliances, they are regarded as being closed by Class 1 closing appliances in determining the effective length. The total effective length is obtained by adding to the length determined by (1) the difference between this length and the length of the ship modified in the ratio of—
B₁ — b
——— where b = breadth of deck opening ;
B₁
B₁ — b
where ——— is greater than 0·5 it is taken as 0·5.
B₁
Deductions for Superstructures.
Rule LIII.—Deductions for Superstructures.
Where the effective length of superstructures is 1·0 L, the deduction from the freeboard is 14 inches at 80 feet length of ship, 34 inches at 280 feet length, and 42 inches at 400 feet length and above; deductions at intermediate lengths are obtained by interpolation. Where the total effective length of superstructures is less than 1·0 L the deduction is a percentage obtained from the following table:—
| Superstructures. | Total Effective Length of Superstructure (E). | Line. |
|---|---|---|
| 0. | 0·1 L. | |
| Per Cent. | Per Cent. | |
| All types with forecastle and without detached bridge | 0 | 5 |
| All types with forecastle and detached bridge* | 0 | 6·3 |
- Where the effective length of a detached bridge is less than 0·2 L, the percentages are obtained by interpolation between lines B and A.
Where no forecastle is fitted the above percentages are reduced by 5.
Percentages for intermediate lengths of superstructures are obtained by interpolation.
Sheer.
Rule LIV.—General.
The sheer is measured from the deck at side to a line of reference drawn parallel to the keel through the sheer line at amidships.
In ships designed to trim by the stern in service, the sheer may be measured in relation to the load line, provided an additional mark is placed at 0·25 L forward of amidships, to indicate the assigned load line. This mark is to be similar to the load line disc amidships.
In flush deck ships and in ships with detached superstructures the sheer is measured at the freeboard deck.
In ships with topsides of unusual form in which there is a step or break in the topsides, the sheer is considered in relation to the equivalent depth amidships (see Rule XXXV).
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VUW Te Waharoa —
NZ Gazette 1934, No 77
NZLII —
NZ Gazette 1934, No 77
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Rules for determining Maximum Load Lines of Merchant Ships
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🚂 Transport & CommunicationsLoad Lines, Merchant Ships, Marine Safety, Regulations, Superstructure, Freeboard Deck, Bulkheads, Closing Appliances, Bridge, Forecastle, Trunk