I recently discovered a new leak in the bow of my Oday 23. It looks like it might be coming from the anchor locker drain, or it could be the u-bolt just below it. I plan to rebed those fittings this winter. The thru-hull fitting is metal and looks like 1/2 dia. I'd like to replace it with a mushroom head, but am afraid the diameter would be too large for the stem. Any suggestions?