(a) Superstructure. (1) Vessels, shall have a forecastle of at least standard height and a length of at least 0.07L. In addition, if the vessel is less than 328 feet in length, a poop of at least standard height, or a raised quarter deck with either a deckhouse or a strong steel hood of at least the same total height shall be fitted aft.

(b) Double bottom tanks. (1) Double bottom tanks where fitted within the midship half length of the vessel shall have adequate watertight longitudinal subdivision.

(c) Bulwarks. (1) The vessel shall be fitted either with permanent bulwarks at least 39 1/2 inches in height, specially stiffened on the upper edge and supported by strong bulwark stays attached to the deck and provided with necessary freeing ports, or with efficient rails of the same height and of specially strong construction.