A Failed Eruption:
The Dynamite Cruiser Vesuvius
By Mike Bennighof, Ph.D.
January 2024

The latter decades of the 19th century saw a flowering of technical innovation, as steam-powered ships, railroads and telegraphs completely changed the social and economic landscape. In 1867, Swedish inventor Alfred Nobel patented dynamite, a far more powerful explosive than gunpowder.

Dynamite saw extensive use in construction and mining, but attempts to use it as a weapon foundered on its chemical properties. Dynamite is nitroglycerine mixed with diatomaceous earth (the fossilized shells of tiny sea creatures); nitroglycerine is highly explosive but also very unstable. Dynamite is much less sensitive to shock, but it will “sweat” out its nitroglycerine over time which makes it dangerous to store for long periods. Experiments with dynamite-filled artillery shells failed with terrible results; the heat of firing such a shell through a conventional cannon detonated the explosive before it left the barrel. Chicago schoolteacher D.M. Medford solved this problem with a pneumatic gun, using compressed air to fling a small dynamite charge.

In 1883, Medford arranged a demonstration at Fort Hamilton, New York, in hopes of selling his invention to the U.S. Army. Medford failed to get a contract, but one of the observers, Lt. Edmund Zalinski, was impressed enough to start his own series of experiments. Zalinski built ever-larger weapons, and in 1885 showed naval officers a pneumatic gun with an 8-inch bore and a purported range of two miles. Impressed, the U.S. Navy sought funding for a ship armed with the novel weapon.

The dynamite cruiser Vesuvius, in the early 1890s.

Vesuvius was laid down at William Cramp & Sons’ shipyard in Philadelphia in September, 1887. Though classed as a “dynamite cruiser” she was a very small ship, displacing 929 tons. By comparison, the cruiser Baltimore also building at Cramp’s displaced 4,400 tons. Vesuvius could make 20 knots, a good speed for the day, but she was a very poorly-designed vessel. She proved difficult to steer in even mild seas, had a huge turning radius, rolled very heavily and had severe structural weaknesses around the pneumatic gun installation. The three tubes took up about half of the small ship’s internal space.

The pneumatic guns, canted at an 18-degree angle, could not be trained; to aim them the entire vessel had to be turned. Range was controlled by altering the compressed-air charge. Because of her small size, Vesuvius only carried 10 rounds for each gun. Once fired, the projectiles had a very short range — just under 3,000 yards at maximum range, using sub-caliber rounds. Because of the very low muzzle velocity (anything higher would set off the dynamite charge), the rounds tended to drift badly in windy conditions. They did carry a very large charge, 500 pounds of dynamite.

Internal plans of Vesuvius.

Commissioned in 1890, Vesuvius joined the North Atlantic Squadron and underwent test firings. These apparently made little impression on the Navy; plans for a sister ship, authorized in 1889 while Vesuvius was still under construction, were quietly dropped. Vesuvius’ major duty consisted of appearances to “show the flag” at minor festivals and county fairs on the East Coast, but even so her fragile hull wore out quickly and in 1895 she was decommissioned for overhaul.

In early 1897 she rejoined the North Atlantic Squadron, and went to Cuba to join the blockade when the Spanish-American War broke out the next year. She served as a dispatch boat, carrying messages between the fleet off Santiago and Key West. Finally deployed to bombard the Spanish defenses in June, she could operate only at night since the Spanish coast-defense guns greatly outranged her pneumatic launch tubes.

Eight times Vesuvius crept towards the entrance to Santiago’s harbor and lobbed three projectiles toward the harbor on each occasion before speeding away. As the targets could not be sighted from the craft, accuracy was poor and it’s somewhat debatable whether the Spanish even realized they had been shelled — while American commanders claimed the bombardments had “great psychological effect,” there is no evidence of this from the Spanish side.

The power of Vesuvius: a Zalinski dynamite shell.

“The first shot struck near the ridge of the hills,” an observer wrote later, “and exploded with a tremendous roar. . . . An immense volume of red earth was blown straight up into the air to a height of 200 feet. The effect of the second shot, which struck higher up on the cliff, was similar to that of the first. The third shot went over the hill, and probably reached the supposed location of the torpedo boats in the harbor.”

As soon as the war ended, Vesuvius was laid up in Boston. In 1904 her pneumatic tubes were removed and she was converted into a torpedo test craft, with four tubes of various types, and performed for three years before another overhaul. Recommissioned in 1910, she remained in harbor service at Newport, Rhode Island, until scrapped in 1922.

As a weapons system, Vesuvius represented a waste of $350,000 of tax money but in the continuing tradition of the military-industrial complex represented a great success for Zalinski and the investors in his Pneumatic Gun Company. Many foreign naval officers toured the ship and reported home on their observations; no other navy ever constructed a dynamite cruiser. By the turn of the century, new explosives could deliver just as much force as dynamite without the stability problems.

Vesuvius appears in Great War at Sea: Remember the Maine with the appropriate gunnery factor of zero. She is utterly useless in the game, as she was in life.

Click here to order Great War at Sea: Remember the Maine.

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Mike Bennighof is president of Avalanche Press and holds a doctorate in history from Emory University. A Fulbright Scholar and award-winning journalist, he has published over 100 books, games and articles on historical subjects. He lives in Birmingham, Alabama with his wife, three children and his dog, Leopold.