Hello John, You may be interested in how I replaced the aluminum thru-hull on our early "iron board" M17. I used copper water pipe-it's not bronze but pretty corrosion resistant. Search the posting for "hula pie", "copper", and "thru-hull" to get that info. By using a 45 degree ell as the actual part going thru the hull the drain is as low and close to the bottom as possible and the hose is all downhill-no trapped water. Also I used layer upon layer of glass both inside and out and wrapped over the ell for strength-the prep for this was to grind out a slight "dish" on each side about 6 inches in diameter to accept the layers of glass which were each slightly larger in diameter than the last. Glad to hear of your adventures, Ron Goodspeed M17 "hula pie" #025