So I googled some images of the boat. While the back is open and requires canvas to close, the front and sides look to have substantial solid windows. That picture you posted has a funny angle that makes the saloon appear much shorter than it looks in other pictures. In those, the saloon is substantially closed in with just an open back that one needs to step out into to be in the clear.

Besides, there are many boat designs that are just fine without enclosed bridgedecks - Mainecat, etc. This doesn't make them unseaworthy - even in January. Most catamarans are "open" in the back anyway - to the extent that the large sliding doors are almost always left open.

Nobody is suggesting that the relative "openness" of the boat caused the dismasting, are they?

Mark