A former Navy minesweeper which was later refitted and used in the Bahamas as a cable layer, the globe-trotting MV Mahi ended its floating life as a research vessel for the University of Hawaii and adds a been-everywhere, done-everything mystique to underwater Oahu. Placed on the bottom in 1982, the Mahi was turned completely around and partially collapsed during Typhoon Iwa, so it is no longer recommended to divers as a penetration wreck dive. But even without an accessible interior, the 176-foot wreck remains the most popular dive site on the west side of Oahu. Cruise over and around it, and you will be rewarded with puffers, nudibranchs, octopuses and possibly even a fly-by of spotted eagle rays. Oahu's ubiquitous white tip reef sharks are usually also in attendance on this site - just another feature that makes the Mahi well worth a visit.