by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- Dynamite guns
- More stable than nitroglycerin
- Air provides a way
- U.S.S. Vesuvius
- Close-support ship
- Technical specifications
- Accuracy poor
- Thanks
Dynamite guns
When we think of airguns we think of quiet, low-powered guns that are safer than firearms because of their limited range and reduced tendency to ricochet. But that’s not the whole story. Over a century ago there was a special type of airgun that was used on the battlefield and the high seas to do major damage. I’m referring to the so-called dynamite guns of the late 1890s.
More stable than nitroglycerin
Dynamite was invented in 1866 by Swedish inventor, Alfred Nobel. He took nitroglycerin, another recent invention (1846) and stabilized it by combining it with silica to turn the sensitive liquid into a malleable paste he called dynamite. He discharged the dynamite with one of his blasting caps, originally perfected in 1863 to discharge nitroglycerin with shock rather than heat.
Dynamite was much more stable than nitroglycerin, but it still had problems. Sometimes the nitroglycerin in the compound “sweated” out in droplets of pure nitroglycerin that were as sensitive as any other nitro. That made the early dynamite a very sensitive product to handle.
Air provides a way
The military was quick to accept the new more powerful explosive, and they soon set about finding new ways to exploit it. One idea was to replace the blasting powder in explosive artillery shells with dynamite. This gave the shells increased power, but it did have a drawback. The conventional method of launching the shell — i.e. via a gunpowder explosion — was deemed too much shock for the dynamite to safely endure. It was too possible for the warhead to detonate inside the gun barrel from the shock of the gunpowder explosion at the instant of firing. A less aggressive way to launch the shells was needed.
Ohio schoolteacher D.M. Medford believed that compressed air would solve the explosion problem, and would also reduce the weight of the gun, since air pressure would be far below the pressure generated by exploding gunpowder. On the other hand, the gun barrels needed to be much longer, to allow the compressed air more time to accelerate the shell.
U.S.S. Vesuvius
Dynamite guns were built for the U.S. Army and also for the U.S. Navy. Today we are looking at the U.S.S. Vesuvius, a purpose-built dynamite cruiser. Her keel was laid in September, 1887 and she was launched April 28, 1888. She was 246 feet long with a beam (width) of 26.5 feet. She displaced 945 tons. She was commissioned June 2, 1890. There were 70 in her crew, and her captain was Lieutenant Seaton Schroeder.
U.S.S. Vesuvius with two guns down and one elevated. From Gas, Air and Spring Guns of the World.
Close-support ship
As long and narrow as the Vesuvius was, she didn’t handle that well in high seas and was not considered to be a good ocean-going vessel. Her strength was closing with a hostile coastline under cover of darkness and aligning herself with the target. Her three guns were 55 feet long and passed through two upper decks at an 18 degree angle. There was no ability to swivel them like the guns on a battleship. They pointed out over the bow of the ship and the entire ship had to be aimed at the target to engage. Minor adjustments consisted of shooting long or short, which equates to beyond or short of the target! Range was determined by the length of time to compressed air pushed against the shells while they were still inside the tubes.
Technical specifications
The guns worked on air compressed to 1000 psi. Compressors recharged the air storage tanks onboard, and could apparently keep up with the rate at which the guns fired. The cast iron tubes had 3/8-inch walls with 1/8-inch brass liners. The 7-foot shells were 14.75-inches in diameter and the bore of the guns was 15 inches. Undoubtedly the shells had something to obturate the bore so air couldn’t get past. The velocity at the muzzle was around 800 f.p.s.
The ship carried a load of 10 shells per tube, for a total of 30. The maximum warhead charge in a shell could be as much as 550 pounds of desensitized blasting gelatin — not dynamite, per se, though dynamite was the main component of this material. With the full weight warhead the maximum range was about 2000 yards, but the warhead could be reduced to 200 lbs. to double the range. It was said when the guns fired they sounded like a loud deep cough rather than an explosion.
The crew was said to be concerned about the use of the dynamite charges. They felt every time the guns fired might be their last, as a warhead could go off inside the thin tubes. Apparently there was a lot of skepticism over first-generation dynamite charges.
Accuracy poor
Accuracy was iffy at best. There is no record of any damage done by the nighttime bombardments, though the Spanish soldiers are reported to have been disconcerted by the quiet flight of the shells through the dark sky and also by the huge devastation they made when they hit. I see a parallel between a Vesuvius barrage and a V-1 rocket attack on London during WWII.
The Vesuvius was not a success. Though the ship did accomplish several fire missions during the war, the accuracy wasn’t up to the standards of traditional naval gunfire. The ship was removed from service at the end of the Spanish-American War and her three pneumatic tubes were removed. She was put back into service again several times for other duties and finally ended service in 1921.
Although a second dynamite cruiser was on the boards, plans were scrapped as soon as the Vesuvius started operations. The advantages of operating with compressed air were more than offset by the severe drawbacks of aiming, short range and inaccuracy.
Dynamite cruisers were built by other nations, but they used different means of compressing the air. Instead of precharged pneumatics, they had pistons that used a charge of gunpowder to compress the air at the instant of firing — making them spring-piston guns.
Thanks
I was inspired to write this review from an article in the United States Naval Institutes’s Naval History publication from June of 2015. A copy of that article by Commander Tyrone G. Martin, USN (retired) was sent to me by a Shotgun News reader, Jay P. Norton. I have known about the Vesuvius since first reading about the ship in the 1957 publication, Smith’s Standard Encyclopedia of Gas, Air and Spring Guns of the World, by W.H.B. Smith, but the Naval History article contained several facts not previously published.