No. 3 Mine.—Timbers blown away on a space of 10-1/2' × 12' at one end, and 6' at the other; inside planking off for a length of 14'; one iron band torn up, and one broken; outside planking off on a space of 18' × 25' × 15'.
No. 4 Mine.—Timbers blown away on a space 4' × 16'; on the sides of this hole, ten timbers were broken; two iron bands torn up, and one broken; inside planking off for a length of 20'; outside planking off for a space of 20' × 23' × 10', and 13 feet.
No. 5 Mine.—The gas sphere of this mine had hit the middle of the outside plates on one of the angle-iron ribs. This rib was torn from the timbers and bent up, nearly 2' in the middle, but not broken. There was an oval hole in the outside plates 4' × 3' between two ribs, which ribs, with the plates on edge riveted to them, were bulged out about 5 inches. The inner plate, one large piece was blown up in a vertical position, after having cut all the bolts and rivets, sixty of 1", and thirty of 3/4", save those that fastened the lower side to the oaken frame and timbers. On a length of 30' and height of 20', the bottom, on all sides of the iron construction, had been bent inwards; the greatest bend was about 5"; three deck beams above had been broken.
By the joint effect of all the mines, almost all the iron deck beam knees had been rent from the side, and there was an opening between deck and hull on both sides for a length of about 130 feet.
Experiment at Kiel.—Target:—A large gun-boat, greatly strengthened internally by solid balks of timber.
Torpedo:—200 lbs. gunpowder. It was placed nearly under her keel, at a distance of 15 feet.
Effect of explosion:—Complete destruction of the vessel.
Experiment in England, 1874.—Target:—A rectangular iron case 20' long, 10' high, and 8' wide, divided into six compartments by means of one longitudinal bulkhead midway between the front and rear faces of the target, and two athwartship bulkheads equidistant from the ends of the target. Thickness of front and rear faces 11/16", of longitudinal bulkhead 1/4", of athwartship bulkheads 3/8".
Torpedo:—100 lbs. of gunpowder, enclosed in a spar torpedo case and fired by two detonators. It was exploded in contact with the target, 7-1/2' below the surface of the water, and 7' from top of target.
Effect of explosion on the target:—"Front of centre compartment destroyed and top blown off. Plate representing inner skin destroyed. Back of centre compartment (rear face of the target) much bulged, and penetrated; the hole measured 36' × 15". Large portions of the target were thrown to a height of 150 to 200 feet, and from 80 to 100 yards' distance."