This weapon was originally fitted aft, above the electric motor and gasoline engine. Little is known about this weapon. There is no record of it being fired and it was removed during the modifications made during the winter of 1898-99.
Charles Morris described the gun as follows:
"Directly above this [the torpedo] expulsion tube is placed the Holland Pneumatic Dynamite Gun of 8.425 inches bore, having a fixed elevation of 15 degrees, but by filling and emptying the trim tanks this can be increased or decreased. The muzzle of gun is fitted with a water-tight cap. It will discharge a projectile of 222 lbs. weight, charged with 50 to 80 lbs. gun cotton, giving a range in the air of 1000 yards or 30 yards when fired under water. It is operated by air and gun-powder and is quickly handled. Six or more of these projectiles can be carried."1
In a letter to Captain Frederick Rodgers dated March 28, 1899, Lieutenant Nathan Sargent reported: "The forward pneumatic gun was then tried with air pressure only, the gun powder cartridges, which are to be used in connection with the air pressure not having arrived yet. The gun was loaded with a wooden projectile, three feet long by eight and a half inches in diameter and was fired with six hundred pounds pressure. The projectile was thrown four hundred yards without any divergence from the line of fire."2
The Navy Department had little interest in the gun, however, and the gun was not tested in subsequent Navy trials. The gun is an earlier version of patent 708,552 entitled "Submarine or Other Gun" which was submitted by John Holland on September 13, 1898 and illustrated below.
1 is the barrel of the gun.
2 is an air reservoir or jacket about the barrel to receive and hold a charge of compressed air.
3 is a tubular slide-valve adapted to interpose between the breech chamber 4 and the air reservoir.
6 is the breech-block which closes the breech of the gun.
7 is the discharging-valve which controls air passage 5a
P is the projectile in the gun
C is the gun powder cartridge
The specification for the USS Holland describes the torpedo system as follows:
"Consists of one 'lower deck tube, Type 2, for 45 cm. x 11-ft. 8-in. White-head torpedo,' constructed after the plans of the Bureau of Ordnance. This is placed at the extreme forward end of the ship, opening outboard, 3 feet below the light waterline. The cap is hinged, lifting upwards and operated by worm gearing from inside the ship. Cap make a water-tight joint when closed against a rubber gasket.
Air at 50-lbs pressure per square inch is used for expulsion of torpedoes. Ten pounds per square inch being used to empty expulsion tube of water.
"The ship has the capacity for carrying three 45 cm . x 11-ft. 8-in. White-head torpedoes, and means of compensating for each and every one."
The torpedoes were loaded through the torpedo tube using a specially built "cage" (shown below) to lower the torpedo into the water and insert it into the tube from the outside. Once the torpedo was in the tube, the outer cap was closed, the tube was drained, and the torpedo hauled into the interior of the submarine.
The Whitehead Mark I torpedo was powered by a three cylinder reciprocating engine powered by compressed air supplied from an air flask (max 1350 psi). The warhead consisted of 118 pounds of wet guncotton. The range was 800 yards at 26.5 knots. The air flask was charged from the submarines compressed air supply shortly before the torpedo was fired."3
ÓCopyright 1999,2000,2001,2002 Gary McCue