New Tandem Cat Design launched in St. Croix, US Virgin Islands...

I wonder if you could get the same frequency effect with a stabilized monohull as the starting point rather than a cat?

I.e. a tandem center section stabilized by two small amas.

Or maybe a tandem proa (just one ama)?

 

I believe a stabilized tandem-monohull would have a similar frequency effect, maybe less so in beam seas though.

 

Beam seas are where stabilized monohulls normally shine though, IIRC, since the low displacement of the amas means they submerge deeper before effectively resisting thus a slower rolling motion than with a true trimaran.

Which does bring up one issue now that I think of it: a tandem hull demands at least some accommodations be placed up high which puts them where the range of motions can be greater. Hmmmm ... maybe a tandem "stabilized bi-hull" with most accommodations in the hulls but a salon/flying bridge over the air gap?

Also, might make for a nice place to tuck a launch.

 

"the low displacement of the amas means they submerge deeper before effectively resisting thus a slower rolling motions than with a true trimaran."

True, as long as the slower rolling motions don't go lesser than 0.5 HZ. Not sure why, but something about the human anatomy makes us more sea-sick at lower frequencies according to ISO 2631/3 and BS-6841 standards.
Colwell gives a nice summary of the motion sickness experiments and research, link- http://www.dtic.mil/dtic/tr/fulltext/u2/a214733.pdf

"Hmmmm ... maybe a tandem "stabilized bi-hull" with most accommodations in the hulls but a salon/flying bridge over the air gap?"

Sounds like a great idea