Mystery leak.
Chris, Can you stay aboard or nearby in order to check the bilge every short while for a day? Have you ruled out the rudder shaft or if none, the gudgeons, etc? I don't know how deep your bilge is but if it was half full after five days, surely a little trickle would become apparent with patience. Are you limited to a small area to look in your bilge? With luck you could at least determine the direction the leak was coming from, forward, aft, port or starboard. Determine the maximum level of a full bilge and look for through hull fittings between there and the waterline. It could be something as simple as a loose hose clamp or a seeping fitting. Failing everything else and ruling out water incursion from above the waterline and assuming that the maximum safe height of the bilge is relatively close to the waterline, you might want to enlist the aid of your local boat yard. With the bilge totally full (fill it with a garden hose if necessary), they could haul you out and put the boat on stands for the day. Get a comfortable folding chair, sit in the shadow of the boat and with something to eat and drink, maybe a radio to while away the hours, sit down to watch for a trickle coming OUT of the boat. Wait a minute, you have an E25, how about doing the same with a trailer, you own or a borrowed one? Please keep us all informed of the eventual outcome. Glyn Judson, E31 hull #55, Marina del Rey, CA