Nautilus Under Sea

Nautilus Under Sea is the smallest and most characterful vessel in the Mexican fleet of Nautilus Adventures. The hull went into the water in 1968 as the submarine tender for Dr. Perry of Perry Oceanographic, and later became the legendary Undersea Hunter, carrying expeditions to Cocos Island and appearing in IMAX shoots across the Pacific. A shipyard refit stretched the hull to 32 metres and added a new superstructure, an extended sun deck, a bulbous bow and a stabilisation system. The name on the bow changed; the character did not.

There are just 19 guests and nine staterooms, each with its own bathroom and shower and its own climate control. The crew numbers nine — roughly one crew member for every two guests. The lower deck cabins still wear the polished woodwork of the original ship, the Emerald premium suite sits on the sun deck next to the hot tub, and the Rosario stateroom beside the dive deck is wheelchair accessible, which is rare on a dive vessel.

The ship works out of Cabo San Lucas and La Paz on two big themes. The first is the Revillagigedo archipelago, which everyone simply calls Socorro: 235 nautical miles into the open Pacific, a day of crossing and five full diving days at El Canyon, The Boiler, Roca Partida, Cabo Pearce and Punta Tosca. The draw is the friendliest giant oceanic mantas in the world, with wingspans up to seven metres, up to twelve species of shark — hammerhead, silvertip, silky, Galapagos, whitetip reef — and bottlenose dolphins that come to divers of their own accord. The second theme is the Sea of Cortez, the “aquarium of the world” in Jacques Cousteau’s phrase: Las Animas with its hammerheads, La Reina with its baitballs, the sea lion colony at Los Islotes, wrecks, the Loreto and Cabo Pulmo national parks, summer whale shark gatherings in Bahia de los Angeles and the autumn sardine run in Magdalena Bay.

The dive deck is generous, with large camera tables and personal camera storage; dives are made from tenders, with a water-level platform. Nitrox is available but charged separately. The operator has been running trips here since 1978 and holds a certified ISM safety management system — the only dive operator that does.

On board there is an air-conditioned salon with a library and media collection, a dining room, two bars, a freshwater hot tub, loungers on the sun deck, kayaks and paddleboards. The kitchen is a mix of Mexican and North American: an early continental breakfast before the first dive, a hot breakfast after it, lunch, snacks after every time in the water, and dinner served plated or family style.