Cox bolt driving gun - video

[Altair]

The Cox bolt driving gun is designed for underwater rescue and salvage operations. It fires hollow or solid bolts through ship hulls. Hollow bolts are used to supply fresh air to the trapped crew while solid bolts are used for fixing.

More:

Diver Tools - Submarine Bolt Driving Gun

Previously:

steam-powered submarine
The H.L. Hunley, the first submarine to sink a warship
Firefighting shotgun - GIFs and video

[sossol]

I'm surprised that this hasn't been weaponized yet. It would be an easy way to introduce explosive or toxic gas to any vessel for the kill, or a sedative for the capture. Two spikes pumping the components of a hypergolic fuel would make for a bad day on the boat.
Make the tip self-separating and it could be part of a cluster warhead of a torpedo used to sink a vessel. It would be a slow leak, but in a discrete location it could be effective device, and could give the crew time to escape.

[Haroun]

I wonder how it feels to be underwater & firing that gun. I'd think the shock wave would be pretty awful. & hull thickness is a lot more than 3/4".