Sea Hunter

Sea Hunter is a 35-metre (115-foot) vessel operated by the Undersea Hunter Group, built in 1994 as a commercial diving support boat and converted for long-range diving expeditions. Her working past shows in the welded steel hull, the teak work deck, a 3,500-nautical-mile range and zero-speed stabilisers that are lowered into the water at anchor — so she barely rolls in the swell off the island. Ten cabins host up to 20 guests, looked after by a crew of ten.

Sea Hunter runs one itinerary year-round: out of Puntarenas to Cocos Island, 502 km off the mainland. The crossing takes 32–36 hours each way, leaving seven full days of diving at the island — usually three dives a day from two 24-foot fibreglass dive skiffs. Your gear stays on the skiff for the whole stay and tanks are refilled right there, so nothing has to be hauled back and forth between the mothership and the boat.

Cocos is first and foremost about sharks. At Bajo Alcyone, scalloped hammerheads gather over the seamount in schools of hundreds; Manuelita has cleaning stations that draw Galapagos and tiger sharks; Dirty Rock and Dos Amigos bring marble rays, mantas and walls of snapper. The island holds 12 shark species, 4 species of ray, 4 species of sea turtle and 27 endemic fish, including the rosy-lipped batfish. Dives are deep (18–30 m) and often in current: Open Water is the minimum, and the operator recommends the Deep Diver specialty and at least 25 hours underwater. Decompression dives are not permitted, the depth ceiling is 30 metres, a dive computer is mandatory and every guest is issued a Nautilus Lifeline GPS unit. Nitrox on board is free and unlimited — on these profiles that is the main safety margin.

Eight lower-deck cabins have a porthole; two upper-deck suites have large windows, a desk and chair, a flat-screen TV and a bathroom with granite surfaces, and each suite carries original hand-painted artwork by Carlos Hiller. Every cabin has individually controlled air conditioning, an en-suite bathroom, hot water and daily housekeeping. Public spaces include a lounge with sofas and a TV, a separate study with a library and a photo and video editing station, a dining room with five booths and a large sundeck.

The galley turns out American and Costa Rican cooking: three buffet meals a day, snacks between dives, fresh tropical fruit, fish, chicken and beef. Soft drinks and beer are included. Once a year the vessel goes into 4–6 weeks of scheduled maintenance — everything is stripped down, the hull is repainted and all diving equipment is serviced.