Displacement 930 tons;
Length Overall: 252’4”; Breadth: 26’6″; Draft: 9′
The USS Vesuvius was a one-of-a-kind experimental vessel launched in 1888. She was built by William Cramps and Sons in Philadelphia, PA and powered by two triple expansion steam engines, each driving one propeller. The contract called for a top speed of 20 knots, and the Vesuvius made 21 knots at her sea trials for acceptance.
The main battery consisted of three pneumatic cannon, which were mounted in fixed position taking up most of the forward part of the hull. The three guns can be seen protruding from the deck in the photo above. The photo below shows the guns looking forward.
The guns fired projectiles of nitrocellulose and nitroglycerine, explosives that were more stable than dynamite, but still sensitive enough to require the pneumatic cannon for firing. The guns were fired by compressed air, and the hull also had space for large compressed air tanks, compressors, and storage for multiple projectiles.
One purpose of the design was to permit “silent bombardment” of civilian targets, rather than ship to ship gun battles. Popular press at the time of her launch referred to the Vesuvius as the “Dynamite Cruiser” and “The Terror Ship” because the cannon were silent when fired and a target could be bombarded without warning. The first indication of attack would be the explosion of the projectiles.
The Vesuvius participated in 8 shore bombardments of Santiago, Cuba, during the Spanish-American war. Although some reports of the results were positive, particularly the fear induced in the civilian population, the ship was largely unsuccessful. Aiming the cannon required orientation of the ship, as in the older former mortar-equipped bomb vessels, and the Vesuvius was also poorly armed to counter an attack from even small vessels coming out from the shore. Vesuvius mounted only three 3-pounder guns in addition to the pneumatic cannon.
The Vesuvius had an extremely sharp hull, with an overall length of 252 feet, breadth of 26.5 feet, and draft of 9 feet. Her lines at given below in a plan obtained from the National Archives. The original plan is dated 1887.
Below is another contemporary plan including an outboard profile drawing of the ship, also from the National Archives.
One consequence of the rather extreme hull design and the powerful engines became evident when she was came under attack from shore based craft during one bombardment of Santiago. Lacking adequate defensive weaponry, the ship needed to reverse quickly to escape the attackers and nearly put her stern under water due to the power of the propellers and the low freeboard astern.
As a result of the experience with the Vesuvius, there were no more pneumatic cannon equipped ships built, and in 1904-5 Vesuvius was refitted as a torpedo-testing vessel, equipped with three 18 inch torpedo tubes and one 21 inch tube. At least one of these tubes was mounted in the hull, athwartships. She conducted torpedo experiments for a couple of years before ending up at Newport as a station ship until sold and scrapped in 1921.