[SeniorMoment]

Covered up exactly like the U-boats that lurked right off the coast of the United States during WWII - or am I wrong about that?

[cripplecreek]

There are at least two U-boats at the bottom of the Gulf of Mexico.

[DuncanWaring]

The way I've heard it, people could read by the light of burning ships offshore after the ships had been torpedoed.

Difficult to 'cover up' U-boats in that situation.