Wife and I did a Caribs cruise on her a few years ago . Wonderfull vessel and very comfortable in a heavy sea .
She is Not a Cat but a SWATH ( Small Water Plane Twin Hull ) Technology invented and developed in NoVa Scotia Canada . US use the technology for stable "Gun Platforms "
The hull has two large cigar shaped pontoons which are submerged as opposed to a Cats 2 hulls .
Very well appointed accomodations with few passengers and lots of crew ; Luxury .
I saw somwhere on SN that she is now a Casino as opposed to a cruise ship .
The line of shafting was incorect at design and she had a low top speed which made repositioning from the Caribs to the Meddi a long event .
yeah i watched a do***entary on them. very good in rough sea, out match any cat or mono for stability. can have a reasonable top speed. but very economical as you can have a very narrow hull on top of the water as all the bouancy is under the water.
Here's a link to the principle of this type of vessel posted a while back on the stealth ship thread.
There are some pictures in the gallery of this type of vessel in a dry dock where you can see what is underwater but I can't find them so the link is all I could come up with.