Hull Construction Regulations (C.R.C., c. 1431)

11 (1) Every ship of 50 m in length or more shall be fitted with a watertight double bottom that

• (a) in ships of no less than 50 m but less than 61 m in length, extends at least from the forward end of the machinery space to the collision bulkhead, or as near to that bulkhead as is practicable;

• (b) in ships of no less than 61 m but less than 76 m in length, extends at least from the forward end of the machinery space to the collision bulkhead and from the aft end of the machinery space to the afterpeak bulkhead, or as near to those bulkheads as is practicable; and

• (c) in ships of 76 m or more in length, extends at least from the collision bulkhead to the afterpeak bulkhead, or as near to those bulkheads as is practicable.

(1.1) Ships of no less than 24 m but less than 50 m in length that carry berthed passengers below the bulkhead deck shall be fitted with a watertight double bottom for the full length of compartments in which passenger spaces are located.

(2) When a double bottom is required by this section to be fitted in a ship, the inner bottom shall be continued out to the ship’s sides in such a manner as to protect the bottom to the turn of the bilge; the inner bottom shall be deemed to be adequate for this purpose if the line of intersection of the outer edge of the margin plate with the bilge plating is not lower at any point than a horizontal plane passing through the point of intersection with the frame line amidships of a transverse diagonal line inclined at 25 degrees to the base line and cutting it at a point one half of the ship’s moulded breadth from the middle line.

(3) Wells constructed in the double bottom for the purpose of drainage shall not be larger or extend downwards more than is necessary for such purpose, and shall not be less than 460 mm from the outer bottom or from the inner edge of the margin plate, provided that a well extending to the outer bottom may be constructed at the after end of a shaft tunnel.

(4) Wells for purposes other than drainage shall not be constructed in the double bottom; the Board may exempt any ship from the requirements of this subsection in respect of any well it is satisfied will not diminish the protection given by the double bottom.

(5) Nothing in this section shall require a double bottom to be fitted in way of watertight compartments used exclusively for the carriage of liquids, if the safety of the ship will not be impaired in the event of bottom or side damage by reason of the absence of a double bottom in that position.

(6) The Board may exempt any ship, other than a ship of Class I, from the requirements of a double bottom in any portion of the ship that is subdivided by application of a factor of subdivision not exceeding 0.5 if it is satisfied that the fitting of a double bottom in that portion of the ship would not be compatible with the design and proper working of the ship.