Steve, Try Blue Heron Marine for the housing. It is an Airmar transducer with a Ray label. I'd go with your gut. If I remember correctly, you are on a mooring without a charger. If the leak gets worse, you are literally sunk!
Sorry! Joel 35/3 Annapolis On Thu, May 9, 2013 at 11:09 AM, Stevan Plavsa <stevanpla...@gmail.com>wrote: > I installed an ST40 thru-hull in my bow where the old knot-meter thru-hull > used to be. Same size hole and all. Backing block was completely dry and > rot free so I left it alone and didn't replace it. I used 4200 to seal the > thing in there. Now, the hole is located at the 'vee' of the hull and the > instructions say "hand tighten only". Well, I hand tightened alright, but > like .. hand TIGHTENED. Apparently I'm a lot stronger than whoever wrote > the instructions ... I'll get to that later. > > As soon as the boat was floating I went in and had a look at all of the > thru-hulls .. all but one, of course, the new knot meter! I had also > replaced a thru-hull for the galley drain located just behind the > companionway steps this winter and last year I replaced three others. No > problems with any of those. > > I'm blaming a stressful launch for my failure to check on that thru-hull. > Anyway, it was leaking. We only discovered while underway half way back to > the club. I didn't want to go back because I swore I'de never go back there > after my experience with haul-out and launch this year, it's a terrible > place. I figured if I have to haul the boat I'll do it somewhere else and > there are other places. The leak wasn't sinking the boat or anything but I > noticed something odd .. a previous owner had glassed over the limber hole > from the bow section to the bilge. So, the bilge pump wasn't going and the > bilge water wasn't rising so that's another reason I didn't notice. I'm on > a mooring so I took the boat to the shared dock to survey the situation. > The leak was pretty bad. The bow had about a foot of water in it after 45 > minutes in the water, not good. > > I bailed all the water out to observe the leak and it was surely coming > from the housing, NOT from between the hull and thru-hull fitting .. > rather, from between the thru-hull fitting (housing) and transducer. Ok I > thought, it's either the housing or the ducer .. I put in the blank, same > leak. Ok, so it's the housing, WTF. > > I messed with it until I got the leak slowed down to a trickle and left it > alone. Yes both o-rings were present on both the transducer and blank plug, > I had also lubed them with the provided silicon lubricant. This housing > keep in mind, is the newer design with the flapper valve, whole thing is > plastic. I drove back to check on it again later that evening and the water > ingress wasn't too bad. I bailed the half bucket of water out and called it > a night. > > The next morning I took the day off work and started making calls to local > marinas pricing out a haul out and calling the chandleries to find a > replacement thru-hull. No one had what I needed in stock and everyone was > busy with launch, they could make time for me, but it was going to be > expensive! I weighed my options and decided to try the cheapest, lowest > risk option first .. bigger o-rings. This was recommended to me by an > employee at one of the chandleries and he pretty much saved the day. I > happened to have the EXACT o-ring on board! One of them anyway, the larger > upper one .. I had purchased a pack of replacement o-rings for the fuel > fill, there were three o-rings in the package so I had two left, just > enough for both the plug and ducer! > > This slowed the ingress down to a trickle, barely noticable. After 45 > minutes there was maybe two tablespoons of water in the bow. Ok, now we're > making progress. I went to home depot and bought a pack of assorted o-rings > but none of them were the right diameter or thickness ... I also purchased > yellow plumbers tape. I put a few wraps around the ducer UNDER where the > lower o-ring is located and slipped the o-ring over the layers of plumbers > tape. LEAK STOPPED. Just about anyway, if I 'jiggle' the transducer I can > get it to leak but if i leave it alone the area remains dry. > > My theory is that I overtightened the thru-hull fitting causing it to > deform due to it's location on the curved part of the hull. The hole is > flat mind you and the flange fits in just fine but I don't know .. that's > my theory. I know that these plastic thru-hulls are prone to cracking when > over-tightened... I don't think mine is cracked because the larger o-rings > have stopped the leak. > > So finally my questions: > > 1. is my thinking ok? Is it possible that the housing IS in fact cracked? > I can't see any cracks. > 2. how critical is a boat haul? If the housing isn't cracked what are the > chances that it COULD crack while in some chop or something? I imagine the > hull is pretty rigid up there at the vee of the bow, it's thick and not a > large unsupported area. > > My gut tells me to haul the boat and replace the thru-hull with > raymarine's bronze version but thats' going to be a very expensive > exercise. The original knot meter fitting was plastic as well and that > lasted 32 years. > > Thanks all. > > Steve > Suhana, C&C 32 > Toronto > > > > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com > CnC-List@cnc-list.com > > -- Joel 301 541 8551
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