At Anchor Roll Stabilizers:
 

Roll Stabilizers (flopper stoppers) in open position are 42" x 28.5" giving you 1200 sq. inches of surface area. Flopper stopper plates and all the hardware are made from type 316 stainless steel for ultimate corrosion resistance. The entire unit weighs only 34lbs. and can fold to 15.5" x 42" so that it can be stowed easily. Chain bridle and welded hinges make for an extremely rigid device to handle the roughest anchorages. Use one unit for boats up to 50' and two units for boats up to 80'. Do you want to keep your wife on board...then here you go!