Re: 6 Americans, 1 Brit vanish at sea
It should be better appreciated by all sailors how vulnerable a vessel is to a knockdown/rollover by a freak wave once the average wave height approaches the beam of the vessel. It certainly sounds like she was in those conditions. Much of heavy weather vessel management is maintaining control and attitude to keep the vessel in the least vulnerable attitude. A small steering mistake or failure that the vessel would normally survive can be fatal if it happens at the wrong moment.
"Freak wave" is a poor term because there are probably two or three waves of the right size and shape at any one spot in severe conditions every day. The chances of a boat being at that spot are very low, however. People circumnavigate and never see one.
Rig loss in such an event could quickly lead to sinking if the attached wreckage damaged the hull. The remaining hope, if she was rolled, is that all communications ability was lost and rescuers are looking for masts and overlooking the boat. It's a pretty grim and slim hope.
A ship strike would also be high on the list in those conditions. Lookout becomes difficult on both sides and there is a tendency for big ship lookouts to assume that no one would be out in such conditions anyway. I've seen that effect in coastal waters on nasty days.
A large piece of debris, just awash and invisible until one wave before.....
The sea is a dangerous place, even for the most experienced and competent.