The recent sinking of the M/S Explorer off the coast of Antarctica, which left 154 passengers and crew members huddled in small lifeboats on the frigid water for hours, drew attention to the growing popularity of Antarctic tourism. It also raised questions about the safety of navigating the unpredictable, icy seas.

''There is no question that going to extreme parts of the world has some risk attached,'' said Sven Lindblad, president and owner of Lindblad Expeditions, an adventure travel company that operates the ship Endeavor in Antarctica. He advised passengers to ``make sure the ship you choose is ice-strengthened, but above all, ask about the experience of the captain and crew.''

The Explorer, built by Lindblad's father and sold to Canada-based G.A.P. Adventures after many years of sailing around Antarctica, was seaworthy, with an ice-hardened double hull, Lindblad said. Moreover, it had a veteran crew of polar mariners.

''It seems it was just an odd occurrence,'' Lindblad said.