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.
How do two ships in the wide ocean collide? It seems unlikely, and yet it happens all the time. Often, the ocean is not all that wide. Many collisions occur in shipping lanes and port approaches, where ships are brought together in close proximity. Here are some videos of actual collisions between ships: