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

123 (1) In this section, freeboard plane means the plane that is parallel to the deepest load waterplane of a ship and tangent to the line of sheer taken at the level of the upper surface of the main deck, excluding any raised portions thereof, but including any sheathing.

(2) The door-sill or coaming top of every

• (a) exterior crew access opening

  • (i) in a wheelhouse,

  • (ii) through which no flooding could occur into a space below the main deck, or

  • (iii) located on any deck, other than the part of a forecastle deck in the bow section or the main deck, and through which flooding could occur into a space below the main deck, and

• (b) interior crew access opening that gives direct access from a space above the main deck to a space below the main deck

shall be not less than 150 mm above the deck outside the door-sill or coaming.

(3) Subject to subsections (4) and (5), the door-sill or coaming top of every exterior crew access opening, other than a wheelhouse door opening, located on the part of a forecastle deck in the bow section or on the main deck and through which flooding could occur into a space below the main deck shall be not less than 610 mm the deck outside the door-sill or coaming.

(4) Where a crew access opening described in subsection (3) is located on a raised portion of the main deck extending aft not more than three-quarters of the length of the ship, the height of its door-sill or coaming may

• (a) in the case of a door-sill or coaming located in the part of the forward half-length of the ship not in the bow section, be reduced by 460 mm or an amount equal to one-quarter of the vertical distance between the freeboard plane and the upper surface of the deck outside the mid-point of the opening, whichever is the lesser;

• (b) in the case of the door-sill of a doorway located in the aft half-length of the ship, be reduced by 460 mm or an amount that would reduce the height of the door-sill to a level 610 mm above the freeboard plane, whichever is the lesser; and

• (c) in the case of the coaming of a hatch located in the aft half-length of the ship, be reduced by 305 mm or an amount that would reduce the height of the coaming top to a level 610 mm above the freeboard plane, whichever is the lesser.

(5) The door-sill or coaming top of every exterior crew access opening referred to in subsection (3) on a ship that has

• (a) no sleeping accommodation on board,

• (b) no accommodation of any kind below the main deck, and

• (c) a type ‘A’ closing appliance fitted to every crew access opening that gives direct access to a space below the main deck

shall be not less than 150 mm above the deck outside the door-sill or coaming.