Here’s a Wired story on what the Navy’s doing in Japan:
… The contamination may be spreading. But so is the Navy’s assistance role in the relief effort. The 7th Fleet said it expects the U.S.S. Tortuga to arrive on Tuesday at the eastern coast of Hokkaido, carrying two heavy-lift MH-53 helicopters. It’ll pick up Japanese troops and vehicles and send them on to Aomori, in northern Honshu. Four more ships are expected to arrive starting on Wednesday: the Blue Ridge, the Essex, the Harpers Ferry and the Germantown.
Retired Capt. Jan van Tol, who commanded the Essex during the 2005 tsunami relief missions in Indonesia, explained that heavy-lift helicopters are needed “given the likely damage to coastal transportation infrastructure and the rugged Japanese terrain.” He told Politico, “Essex is on her way up from Malaysia (means a week away…), and other big decks will no doubt be assigned. They’re the real assets for this given their heavy helo lift capacity, though the carriers will no doubt get the headlines with their SH-60s. Remember that operating the heavy helos is not merely a matter of the deck space (of which the CVNs obviously have a lot more), but also of the aircraft maintenance capability needed to keep the helos operating (and I expect they’ll be worked very heavily).”
–Despite Contamination, Navy Copters Keep Aiding Japan (emphasis added)