Tortoise, a 115-foot, eco-friendly superyacht built in 2015 by Arcadia Yachts, is essentially a fiberglass floating fortress—and it is currently available for charter in the Mediterranean. For about $112,000 per week, plus expenses, guests can escape the winter blues and find solace aboard with its contemporary interiors lavishly designed by the renowned Italian firm Poltrona Frau, known for its decadent leathers.

Dressed in an ocean-like turquoise-and-white motif, the yacht also brings the outdoors in, thr…