(6)In [section 331-A and this section,] [ Substituted by Act 21 of 1966, Section 28, for " this section" (w.e.f. 28.5.1966).] the expression "grain" includes wheat, maize, oats, rye, barley, rice, pulses and seeds, and the expression "ship carrying a cargo of grain" means a ship carrying a quantity of grain exceeding one-third of the ship's registered tonnage reckoning one hundred cubic feet or two tons of weight of grain as equivalent to one ton of registered tonnage.Sub-division load lines