The Coast Guard spends much more time thinking about how to keep ships from sinking, than it does about how to sink them. But because the Coast Guard is tasked with maritime security and because of the potential for terrorists using a ship as a means of attack, the question has become relevant. It becomes important when you consider, is the Coast Guard adequately armed for its missions. I’ve mentioned several times that I don’t believe the 57 mm gun is adequate to stop a medium to large ship being used as a weapon. I’ll try to explain why I have reached that conclusion and offer some examples.

Stopping–keeping it from reaching the target–rather than sinking a ship is probably more the relevant criteria, but generally ships don’t sink rapidly, particularly if you are trying to do it with a gun, so almost inevitably it is necessary to do enough damage to ultimately sink the ship if you are going to stop it in a timely fashion. Many of the ships that I will talk about continued to fight on for over an hour after the first hits were registered. Think of sinking a close surrogate for stopping a ship before it reaches its objective.

There are of course many examples of ships either surviving grievous attacks or alternately ships sink after a single hit. What it takes to sink a ship is highly variable and at best probabilistic. Its highly dependent upon ship design and preparation, but the most important variable seems to be size.

World War II experience

Over a long period, I’ve made an informal study of this subject. The primary source I used was the US Navy Report of War Damage series available here. The same index also includes reports of individual ship damage and reports of damage to British warships. I would also recommend the “Destroyer Report: Gunfire, Bomb and Kamikaze Damage, 17Oct41-15Aug45” which includes annotated damage control plates. The amount of damage these little ships took and in some cases survived is truly amazing.

The US Navy Report of War Damage series briefly outlines all incidents of damage to US Navy Battleships, Carriers, Cruisers, Destroyers, and Destroyer Escorts as they were known at the time the document was published and includes diagrams of the location of hits. Continue reading →