'Nova: Why Ships Sink,' on PBS

So, "Nova" asks, could more accidents happen? Some developments would seem ominous, notably that -- as the show reports -- modern cruise ships are extremely tall, displacing their center of gravity. The higher center of gravity reduces the roll but increases the possibility of capsizing. The show also ran several tests of steel -- modern steel and Titanic-era steel -- and the comforting news is that modern steel is seven times stronger. However, that didn't help the Costa Concordia, which brushed against an underwater rock outcrop. Divers later discovered a buckled strip of steel that had been sheered from the ship's side.

One other cautionary move before you book that trip -- check to see if musician Moss Hills is on the passenger manifest. Mills heroically saved passengers on two stricken ships -- the misbegotten Achille Lauro, which sank in 1994, and the Oceanos, which sank in 1991. He's also interviewed -- and says he loves cruise ship work.

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