I had to replace those through hulls on my M17 as well. As others have already said, they are 1-1/2" outside diameter. Mine were crumbling but he hoses were in good shape. I cut/ground the old through hulls out and replaced them with some nice 1-1/2" stainless steel tubing which I glassed into place. The boat spent 10 summers in salt water before I purchased it. It's definitely a good idea to check those annually and keep some tapered wooden plugs on hand for emergencies. If you get a bad leak there only plugging the drains (probably from the outside) or a very quick trip to the launch ramp will save your boat! Mark Dvorscak M23 Faith (Former M17 owner) -----Original Message----- From: montgomery_boats-bounces@mailman.xmission.com [mailto:montgomery_boats-bounces@mailman.xmission.com] On Behalf Of GILASAILR@aol.com Sent: Wednesday, October 03, 2007 9:21 PM To: montgomery_boats@mailman.xmission.com Subject: Re: M_Boats: M-17 early deck model cockpit drain Sorry to ask a 'dumb' technical question - my boat is not here at the moment. Does anyone know the size tubing used on the early model cockpit drain from the cockpit sole to the thru-hull pipe? Maybe I should go look in the MSOG technical section for repairs - I seem to remember someone replacing the pipe thru hulls............. Trailing off into the sunset -albeit a BEAUTFUL one............ GaryO 1/2 yellow 1/2 white M-17 16 days to Lake Havasu Team Geezer Racing.....Old and in the Way Arizona Sailing Squadron ************************************** See what's new at http://www.aol.com _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats