The tonnage of ammunition in boxes is equal to its weight: about 12 boxes make one ton.
BOMB Ketch. The bomb ketches upon the old establishment carry one 13 inch and one 10 inch mortar; with eight 6 pounders, beside swivels, for their own immediate defence. The modern bomb vessels carry two 10 inch mortars, four 68 pounders, and six 18 pounders carronades; and the mortars may be fired at as low an angle as 20 degrees; though these mortars are not intended to be used at sea, but on very particular occasions; their principal intention, at these low angles, being to cover the landing of troops, and protect our coast and harbours. A bomb ketch is generally from sixty to seventy feet long from stem to stern, and draws eight or nine feet water. The tender is generally a brig, on board of which the party of artillery remain, till their services are required on board the bomb vessel.
Instructions for their Management and Security in Action.
1. A Dutch pump, filled with water, must be placed in each round top, one upon the forecastle, one on the main deck, and one on the quarter deck; and furnished with leather buckets, for a fresh supply of water.
2. The booms must be wetted by the pumps before the tarpaulins and mortar hatches are taken off; and a wooden skreen, 5 feet square, is to be hung under the booms, over each mortar, to receive the fire from the vents.
3. The embrazures being fixed and properly secured, the port must be let down low enough to be covered by the sole of the embrazure. Previous to its being let down, a spar must be lashed across it, to which the tackles for raising it again must be fixed: this spar serves to project the tackles clear of the explosion.
4. The mortars must not be fired through the embrazures at a lower angle than 20 degrees, nor with a greater charge than 5 lbs. of powder.
5. Previous to firing, the doors of the bulkhead, under the quarter deck, must be shut, to prevent the cabin being injured by the explosion.
6. The bed must be wedged in the circular curb, as soon as the mortar is pointed, to prevent reaction; the first wedge being driven tight before the rear ones are fixed, in order to give the full bearing on the table, as well as the rear of the bed. The holes for dog bolts must be corked up, to prevent the sparks falling into them.
7. When any shells are to be used on board the bomb, they must be fixed on board the tender, and brought from thence, in boxes in her long boat; and kept along side the bomb ship till wanted, carefully covered up.