looking at the drawings of the Cal 20 I'd be very cautious of sailing with the rail buried. Why? Because there is no space between the cockpit coaming and the rail. IF you get a big puff while the rail is dipping you certainly could take on water in the cockpit and with no bridge deck and I see no cockpit scuppers you could start taking water below. IF the mast gets slammed down 90 you'll most certainly take lots of water in the cockpit and most likely below. Keep you lower hatch boards locked in place and if you don't have good sized cockpit scuppers keep a bailing bucket of two in the cockpit.