Okeanos Aggressor II is a 120 ft diesel-powered liveaboard sailing from Puntarenas, Costa Rica, to Cocos Island — a UNESCO World Heritage site 342 miles offshore famed for schooling hammerheads, whitetip sharks, mantas and tuna. She hosts 22 guests in 11 staterooms: nine deluxe cabins with double and twin bunk, a master with queen bed and two large suites, all with private bathrooms. Charters of 8-10 nights give up to seven full days of diving; on board are a spacious salon, shaded cocktail area, sun deck, bar and grill, with all meals and beverages included.