Underwater Cannon

[Soot]

Apparently not such a good idea, here.

The museum is interesting.

[BoomLover]

I found this quite interesting!  Lots of great inventions! Thanks for posting it. BoomLover

[Cannoneer]

Soot,
I don't know who would be the rightful wiiner in a contest for the person who first entertained the idea of a cannon designed to fire below the water line, but I do know that Robert J. Fulton actually experimented with firing cannons under water, and there is a documented letter with sketches that Fulton sent to Thomas Jefferson in 1813 that describes experiments he conducted firing cannons at heavy wooden planks under water. Robt. Fulton finally settled on the concept of using large Columbiads (100-pounders) for this purpose, and they would be able to fire under water by utilizing an air tight box of Fulton's invention, that would be built into the bulkhead of a ship. The airtight locks would allow the guns to be brought into the ship for loading, and to be run out into battery for firing with an airtight seal put in the bore of the gun. Fulton came to the conclusion that with cannon of this size, firing a large enough charge, the guns could penetrate and sink a British ship-of-the-line at a distance of ten feet. I think it's pretty much apparent that the distance of ten feet needed for the under water cannon to be successful, might impose a slight problem in getting the U.S. vessel safely within striking distance of an enemy vessel. It would be my guess that Thomas Jefferson (who was light years away from being an intillectual slouch) may have readily understood the difficulties inherent in Fulton's proposals.

[Soot]

I'd be scared to death to fire a gun underwater, I would think the added pressure would make things quite unsafe.
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[gulfcoastblackpowder]

While it doesn't work well for cannon, it is the work on this type of concept that led to the development of torpedoes, which work elegantly well:

The first usage of the term torpedo to refer to a naval explosive was by American inventor Robert Fulton. In 1800, Fulton launched his submarine, Nautilus, and demonstrated its method of attack using a floating explosive charge Fulton called a torpedo. The submarine would tow the torpedo, submerging beneath an enemy vessel and dragging the torpedo into contact with it. Fulton successfully destroyed demonstration targets in both France and Britain, but neither government was interested in purchasing the vessel and Fulton's experiments ceased in 1805.

...

The first working prototype of the modern self-propelled torpedo was created by a commission placed by Giovanni Luppis (Ivan Lupis), an Austrian naval officer from Rijeka/Fiume, a port city of the Austrian Empire, and Robert Whitehead, an English engineer who was the manager of a Fiume factory. In 1864, Luppis presented Whitehead with the plans of the salvacoste (coastsaver), a floating weapon driven by ropes from the land, and made a contract with him in order to perfect the invention.

Whitehead was unable to improve the machine substantially, since the clockwork motor, attached ropes, and surface attack mode all contributed to a slow and cumbersome weapon. However, he kept considering the problem after the contract had finished, and eventually developed a tubular device, designed to run underwater on its own, and powered by compressed air. The result was a submarine weapon, the Minenschiff (mine ship), the first self-propelled torpedo, officially presented to the Austrian Imperial Naval commission on December 21, 1866.
http://en.wikipedia.org/wiki/Torpedo

(I figured I'd include the bit on Fulton, since he was already mentioned, and Luppis' design was a derivative of his.

[Cat Whisperer]

Soot -

I've seen, in an 1860 something Scientific American, sketches of cannons designed to be shot at very nearby ships under the waterline.  Muzzles were capped with sheet copper and pitch.  Muzzle went through a sealed port in the side.  Effect was to blow the bottom of the enemy ship wide open - sinking it fast.
Don't know if it was ever tried.

[GGaskill]

The water so impairs the flight of the shot that ranges were in the ten's of feet to be effective.  You can imagine the effectiveness of conventional guns at that short a range.

Torpedos, on the other hand, are usually launched at targets beyond the effectiveness of muzzleloading cannon, although they weren't really well developed until the muzzleloader was a museum piece.

[Soot]

I think somebody should post this on the Mythbusters forum, those idiots will try anything.

[Cat Whisperer]

I think somebody should post this on the Mythbusters forum, those idiots will try anything.

Good idea!  (And WELL put.)
It would be entertaining.