Smaller keel cb boats have a good portion of the ballast in the board so keeping it down in severe weather is probably best for self righting. On larger boats the weight normally is a small portion of the total ballast. This set up makes more lateral resistance without the ballast to back it up...the math on this can be found in Skene's Elements of Yacht Design. I think Sparkman & Stevens wrote about this years ago when one of their keel c/b ketches got caught in a hurricane...I think that particular boat was featured in a National Geographic series and design named Gulfstream. Food for thought...if a boat is "hove to" with a drogue out from the bow and the board down, when a wave hits the bow it can pivot around easier and put the beam to weather...enhancing the knockdown probability. Keeping the board up changes the arm and reduces the pivot. Bill