The hull plating of the USS Holland consisted of 24 steel plates laid in eight strakes. The top, bottom, port and starboard strakes were laid tight against the frames, and the other four strakes were lapped on the outside of these strakes and connecting by two rows of staggered steel rivets.
The two transverse butt joints were "planed" making them flush on the outside. The joint was made by double riveting the shell plates to 3/16 inch thick steel "straps" located on the inside of the submarine. The eight forward plates were 0.30 inches thick, the eight midship plates were 0.35 inches thick and the eight aft plates were 0.25 inches thick.
Frames five through thirty were made of 3 x 3.5 inch angle bar installed with the heel against the inner shell plates. Frames one through four were made from 3 x 2.5 inch angle bar. The frame spacing was eighteen inches except between frame thirty and thirty-one where it was twenty-four inches. The frames were riveted to the hull using a single row of rivets with a liner under the outer hull plates.
On July 24, 1899, the Holland Torpedo Boat Company ran a test on ring stiffened cylinders subjected to external pressure. A 3/8 scale model of a portion of Hull No. 8 was built complete with the turret and access hatch. This model was placed in a tank where it was subjected to external hydrostatic pressure. At a pressure of 110 psi (equivalent to a depth of 253 feet), the hatch seal began to leak. The tests were stopped and the hatch seal was repaired. A pressure of 140 psi was applied during the second test with no noticeable flattening of the structure. At 150 psi, the structure showed slight deformation. At 175 psi (corresponding to a depth of nearly 400 feet), rivets began to crack and the test was halted. In his report dated August 7, 1899, Captain John Lowe argued that these results can be applied directly to the full sized submarine.
The ballast tanks, trimming tanks, compensating tanks and gasoline tank were "all of sufficient strength and stiffness for the purposes of the ship."1 Stapling made from 2.5" x 2.5" x 5 lbs. steel angles was used to ensure watertightness.
The deck plates in the machinery and armament spaces were made from 15 lbs steel plates. The beams beneath the deck were made from 2.5" x 2.5" x 5lbs. steel angles.
The superstructure was made from 7.5 lbs plate with 2.5" x 2.5" x 5 lbs steel angles spaced 36 inches apart for support. The superstructure provided a flat deck 37 feet long with a maximum width of 3 feet 7 inches in way of the turret.
The turret or conning-tower was made of 1 inch thick bronze with a clear opening of 18 inches. The access hatch was sealed with a rubber gasket and secured using a toggle mechanism. One inch by three inch ports were provided to enable the commander to navigate the submarine with the access hatch closed. The design of the turret reflects the original intention of providing a telescoping mechanism, but this mechanism was never installed and the turret remained at a fixed elevation.
Two masts were provided in order that the Navy Board of Inspection could observe the movements of the submarine while it was submerged. These masts extended 9 feet 6 inches above the deck and were secured fore and aft with wire rope.
ÓCopyright 1999,2000,2001,2002 Gary McCue