A French naval officer who investigated the ship, M. Montgéry, also wrote a description, published in "Notice sur la Vie et les Travaux de Robert Fulton."[13]
[Illustration: Figure 5.--FLOATING BATTERY _Spanker_ built, in England by William Barnard, at Deptford on the Thames, and launched June 14, 1794. Rigged as a bomb ketch, its length is 111 feet 7 inches in the keel, extreme beam 42 feet 4 inches, depth of hold 8 feet. Upper deck plan also shown.]
It should be noted in regard to what Montgéry wrote about the _Battery_, that in 1821 it had been considered desirable to disarm the ship. The engineer in charge, William Purcell, had reported that as there were not proper scuppers, dirt and water had entered the hull and had collected under the engine and boilers, causing damage to the hull, and also that with guns removed, the _Battery_ would float too high for the paddle wheel to propel the vessel; so it had been decided to remove all machinery as well as the armament.
Montgéry's description, published in 1822, was taken from his report to the Minister of Marine and Colonies. It noted the battery was made of two hulls separated by a channel, or "race," 15-1/2 feet wide, running the full length of the vessel. The two hulls were joined by a deck just above the waterline, as well as by an upper deck, and also connected at their keels by means of 12 oak beams each 1 foot square. The vessel was 152 feet long, 57 feet beam, and 20 feet deep. Sides were 4 feet 10 inches thick, and the ends of the hull were rounded and alike. There were two rudders at each end, one on each hull, alongside the race. The eight paddle blades, each 14-1/2 feet by 3 feet, turned in either direction by stopping the engine piston at half-stroke and reversing the flow of steam. Rigged with two lateen sails and two jibs, the ship sailed either end first. The engine of 120 hp was in one hull and two boilers were in the other. Other sources, Marestier, and Colden in _Procès-verbaux des Séances de l'Académie des Sciences_,[14] gave additional information (some of it incorrect): the engine was inclined, with a 4-foot-diameter cylinder, 5-foot stroke, direct-connected to the paddle wheel, which was turned at 18 rpm. The boilers were 8 × 22 feet with the fireboxes in inside cylinders, each about 5 feet in diameter, and extending about half the length of the boiler from the fire doors. Two fire tubes, each about 3 feet in diameter, returned the gases from the inside end of the fireboxes to the stacks at the firing end. Except at the fire-door end, the firebox was completely surrounded by water. The boiler pressure of about 6 psi was not maintained, varying somewhat with each stroke of the engine.