The 56-meter-long sailing yacht Bayesian sank at anchor of Sicily in extreme weather early Monday morning, with the loss of one dead and six missing. Among the missing are British tech tycoon Mike Lynch and his 18-year-old daughter, Hannah.

Following the sinking, the most common question asked was “How could a well-found yacht of that size be knocked down and sink, even in the high winds and a reported waterspout that were present at the time of the tragedy?”

Was the yacht simply overwhelmed by the weather or was there some aspect of the design or operation of the yacht that made it vulnerable? The immediate answer is that it is just too soon to tell.

Nevertheless, Bayesian was a distinctive vessel, with a 72-meter-tall mast, said to be the tallest aluminum mast in the world. One account of the sinking suggests that the mast failed about halfway up the lofty spar before the yacht was knocked down. Damage done by the impact of the falling broken mast, spreaders, and rigging could have been substantial but seems unlikely to be sufficient to sink the yacht.

One other feature, however, could have made a difference. Bayesian had a lifting keel. At sea, with the keel fully lowered, the yacht had a draft of 10 meters. When entering shallower harbors, the keel could be lifted, reducing the draft to 4 meters.

Of course, Bayesian would have significantly less stability with the keel lifted. It is conceivable that the reduced stability due to a lifted keel was enough to make the knockdown possible. 

Was the keel lifted when the yacht was struck by the severe weather? It is too soon to tell.  So far, James Catfield, the captain of the Bayesian has released a four-word statement — “We didn’t see it coming.”