|I hardwired one of these at the forward end of the v-berth and another on the main bulkhead over the dinette. They move a lot of air, they're quiet and they don't seem to draw much power. Lots of marine stores sell them (mine were from Genco).
Another option is to perch a standard window air conditioner on the foredeck and then construct a plenum leading to the forward hatch from scrounged cardboard and duct tape. Cooling that small space, a good unit can pull the temperature down to the point that ice will form around the waterline. Looks really stylishly yachty, too. (I wish I'd taken a photo - it was a C&C 25.)
C&C 27 Mk IV