13. Instances of General Average.—
The classic example[30] is throwing overboard (or, as it was called, jettisoning) a part of the cargo in order to escape a storm. Thus if there is a ship worth $20,000, freight list, $10,000, and cargo $70,000, of which X owns $30,000, Y $20,000, and Z $20,000, and $10,000 of X's goods were jettisoned, each interest, including X, will bear 10 per cent of the sacrifice; the ship pays X $2,000; the freight list pays him $1,000; and Y and Z pay him $2,000 each; he receives $7,000 and stands $3,000 and so the sacrifice is equally borne by all. Cargo may be burnt as fuel, or lost by a sale or pledge to raise money to continue the voyage; a mast may be cut away to lighten the ship or the engines injured by overwork to escape disaster or expenses incurred by deviating to a port of refuge for repairs; cargo may be warehoused or transshipped; salvage expenses may be incurred in saving the venture from a stranding or sinking after a collision; and all the various and multiform forms of loss sustained and expenses incurred for common safety, within the definition, are made good by the contribution of all.
Ordinarily a jettison of cargo carried on deck does not give rise to general average, although deck cargo is not exempt from contributing its share of the average for other cargo jettisoned for its safety. But deck cargo will be entitled to participate in general average where the goods are of such character as it is customary in the trade to carry on deck; also where the other cargo-owners have expressly consented that it be carried on deck; also usually in coasting and river voyages. The cases excluding deck cargo from average have generally arisen out of sailing vessels and it may be that the rule should be confined to sailing vessels.