On the port side a quadrangular opening was made, and fitted with a construction representing a strong double iron bottom, firmly fastened to an oaken frame that had been put on inside, on the four sides of the opening, and with through-going bolts, 1" in diameter, to the timbers.
Torpedoes:—No. 1.—13 lbs. dynamite, enclosed in 1/12" iron case. It was placed on the starboard side, amidships, 7' below the water line, and 2' 2" from the bottom of the ship.
No. 2.—16 lbs. dynamite, enclosed in a glass vessel. It was placed on the starboard side, 7-3/4' below the water line, 3' from the bottom of the ship, and 40' from her stern.
No. 3.—16 lbs. dynamite, enclosed in 1/12" iron case. It was placed on the port side, 5-3/4' below the water line, 2' from the bottom of the ship, and 30' from her stern.
No. 4.—10 lbs. dynamite, in a case as above. It was placed on the port side, 6-1/2' below the water line, 2-1/6' from the bottom of the ship, and 70' from her stern.
No. 5.—13 lbs. dynamite, in case as above. It was placed 7-1/3' below the water line, 2-1/6' from the centre of the iron bottom.
These five torpedoes were fired at the same moment.
Effect of explosion:—The hull of the ship was lifted about a foot, and sunk in 1-1/2 minutes.
No. 1 Mine.—Timbers broken and thrown inside, into the hold, on a space of about 15' × 8'; three more timbers on one side of this hole broken; inside oak planking rent off on a length of 14'; two iron bands torn up and bent, one of them broken in two places; outside planking torn off on a space of 21' × 12'; several planks still higher up broken.
No. 2 Mine.—Timbers blown away on a space of about 8' square; inside planking torn off on a length of 20'; two iron bands broken, and torn up and bent; and outside planking rent off on a space of 19' × 12'.