Long Island Sound averages 60 ft in depth, with the greatest depth of over 300 ft at the eastern end. Tidal effects are strongest at the narrow western end, where all the inrushing water flow piles up and makes tidal variations of up to 7 ft. Strong tidal currents are also prevalent, and visibility tends to be poorer than the open ocean, especially at depth.
The United States Coast Guard has donated a number of vessels as artificial reefs over the years. They seem to be sensitive about having their vessels shown in a "bad" way, and typically paint out all the markings before turning them over.