I'm not involved at all this year so have specifics to give. Aero engineers have long been involved in competitive sailing. Trimaran not sure, I'd have to look closer at the execution but it could be to maintain a minimum wetted surface at dynamic support speeds while providing the required stability and low speed buoyancy.
Allow me to translate. The new sailing boats are fast as hell.
It isn't completely different. It is a wing standing on end.