There’s a few ways to make an underwater reef.
The first way — the original way — is to be Mother Nature herself, conjure up some algae, and pile it on top of itself until it forms a “three-dimensional framework that is modified in various ways by other organisms” that just so happen to be hanging on or above the sea floor.
The second way: ask oysters to do it (they can sometimes).
Or, finally, do the following:
What you’re seeing in the video above is courtesy of the United States Navy’s participation in RIMPAC (the Rim of the Pacific Exercises) “the world’s largest international maritime warfare exercise” — in (you guessed it!) the Pacific Ocean.
It’s the retired old decommissioned ship the USS Thatch (FFG 43) being hit with torpedoes and missiles in an effort to provide both naval practice (SINKEX it was actually dubbed) AND an artificial reef for fish and other aquatic life.
After it took this huge hit, the ship bobbed in the water for 12 hours, then finally sunk.