Effect of explosion:—Effect produced apparently equal to that by No. 3 charge of 112 lbs. of gunpowder at 12'; indentation being from 1/2 to 1-1/4 inches in the outer skin opposite the torpedo.
10th Experiment.
Torpedo:—19 lbs. of dynamite, enclosed in a case similar to that used in the 9th experiment. It was placed 3·3' from No. 7 frame, 9·25' below the surface of the water.
Effect of explosion:—Hole produced in outer skin, 6·5' × 2' to 5'; inner skin only bulged and slightly cracked in two places. Above the longitudinal frame, a bulge was made in the outer skin 8' × 7', with the above-mentioned hole; below the longitudinal frame the indentation was 14' × 5' and 2·1" deep, with two horizontal cracks 10' x 13', and several inches broad.
11th Experiment.
Torpedo:—112 lbs. of gunpowder, enclosed in a cylindrical case of 3/64" steel, placed in a 3/16" steel case, with 223 lbs. of buoyancy. Ignition effected by a glass igniting bottle. It was placed 5·75' from No. 5 frame, 9·25' below the surface of the water.
Effect of explosion:—There was but little upcast of water outside the ship, but a great upcast through the ship. She immediately lurched to starboard, and on boarding her five minutes after, the target was found full of water.
The effect on the target was as follows, above the 2nd longitudinal frame, where strengthened by the wing passage bulkhead:—Outer bottom blown away from the 4th to the 6th frames for a length of 8 feet and a height of 4-1/2 feet, and bent in 6-1/2 feet. Inner bottom bent in and broken through between the 4th and 5th frames, with an irregular hole 8' square, and between the 5th and 6th frames, a similar sized hole. Wing passage bulkhead was bent in 2" to 3", and riven for a length of 29'; in the water-tight middle bulkhead athwartships the rivets in two vertical joints were completely torn away.
Between the 2nd and 3rd longitudinal frames, and below the wing passage bulkhead, both the inner and outer bottoms were completely blown away for a length of 12 feet and a height of 4 feet. The vertical and horizontal frames between the two bottoms had kept their position unchanged, and excepting that the bracket plate by frame No. 6 was bent, cracked, and torn away, the damage they had sustained was limited to some comparatively slight bending. The open hole formed in the target measured 76 square feet in outer bottom, and 60 square feet in inner bottom.