"It's a triple hull," she said.

It's a trimaran, a yacht with a triple hull.

Beneath the smoothly sliding flanks of the triple hull, the water was so clear that it added to Duncan's feeling of insecurity.

Detectors in the triple hulls responded, registered on control gauges of the navigation deck.

The bottoms of both outriggers had been solidly planked, to afford sitting and standing space for the outboard banks of rowers, creating what was, in effect a triple hull.

Kassad hung on torn metal and pulled himself through a rent in the triple hull of the HS Merrick.

At 100 ft from nose to stern, and 20 ft at the beam, the submarine has a triple layered hull (which can handle depths of more than three miles).