small vessels, made very strong with large beams, particularly calculated for throwing shells into a town, castle, or fortification, from 13 and 10-inch mortars; two of which are placed on board of each ship. They are said to have been invented by M. Reyneau, a Frenchman, and to have been first put in action at the bombardment of Algiers in 1681: till then it had been judged impracticable to bombard a place from the sea.
Bomb Ketch. The old bomb-ketches carried one 13-inch and 1 10-inch mortar, with 8 six-pounders, besides swivels, for their own immediate defence. The modern bomb-vessels carry 2 10-inch mortars 4 68-pounders, and 6 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 coasts and harbours. A bomb-ketch is generally from 60 to 70 feet long from stem to stern, and draws 8 or 9 feet water. The tender is generally a brig, on board of which the party or 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 embrasures being fixed and properly secured, the port must be let down low enough to be covered by the sole of the embrasure. 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 embrasures 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 re-action; 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.