M60 tanks undergo a thorough cleaning before use as reefs
The Artificial Reef Program used four types of obsolete Army armored vehicles as artificial reef materials off the New Jersey coast. These were cleaned at local military bases, loaded onto barges for transport, and pushed off at their final destination. Once the Army had disposed of its excess inventory, the program ceased, around 1999. The Artificial Reef Program has sunk almost 400 tanks altogether, far too many to list them here in this website.
Most of these sharks are in more danger from us than we are from them. Real sharks are ashamed of them.
"Dogfish" is a generic name for a large number of small, generally harmless, and unaggressive sharks, not all of which are very closely related. Smooth Dogfishes are related to Tiger, Bull, and other Requiem Sharks, while Spiny Dogfishes are in a completely different group, more closely related to Angel Sharks. Compare these with the unrelated Chain Dogfish, a "Cat" shark. Sandbar sharks have nothing in common with the others here, except their small size. None of these little sharks is really dangerous, although any of them could give a good bite if provoked. Generally, they will avoid you.