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smp 05-05-2013 10:28 PM

Raymarine ST40 speed transducer nearly sunk me
i followed the instruction to the letter. The transducer is leaking. I put in the plug, it leaks. The boat is in the water and I managed to get the leak slow enough that I can get some sleep tonight but tomorrow i have to pay for a haul out and I have to fix this.

Question is what how?
I doubt I can get the metal raymarine thru-hull for this transducer locally in time. There's only one marina around here with a lift that they'll let you sit in the slings I think 12 hours. So what are my options?

The ST40 is new. I bought it at the boat show this winter and installed it a week ago. Splashed the boat today and did not see any leaks because I failed to check that one! I checked all the rest of the thru-hulls but not that one. Launch is pretty stressful at the yard I was keeping my boat at this winter. The thru-hull is located in the bow and weirdly enough, that compartment is independent of the bilge! So the pump didn't let on like anything was wrong. Anyway....

What do I do now?
I'm going to call around to get the metal version of the thru-hull fitting (ST 40 ships with a plastic thru-hull) but like I said, I don't know if I'll be able to get it. I can't leave the boat in the water like this.

Maybe I did it wrong. Has anyone had this experience before? Both gaskets are present on the transducer and the blank and they both leak the exact same way! It's leaking up between the thru-hull fitting and the transducer of this I am sure. My guess is that the plastic thru-hull has a crack in it.
What a stressful day.

rugosa 05-05-2013 11:17 PM

Re: Raymarine ST40 speed transducer nearly sunk me
Sounds like cracked thru-hull fitting, maybe over tightened. Just installed ST60 through hulls in same C&C model, will double check for leaks at launch this week.

Call Ray @ Ray's Marine Systems Inc. 905-451-3285, best to call 9 am sharp as he leaves office no later than 10:30 for site visits. He is Raymarine authorized dealer and might have part in stock. Not sure where you are, he is in Brampton, ON Rays Marine Systems

Good Luck!

MarkSF 05-06-2013 12:41 AM

Re: Raymarine ST40 speed transducer nearly sunk me
I guess I'm struggling to understand why you can't just look at the thruhull to see if there are any cracks.

Ajax_MD 05-06-2013 05:16 AM

Probably because the transducer and the blanking plug obscure the view when installed.

sailvayu 05-06-2013 07:46 AM

Re: Raymarine ST40 speed transducer nearly sunk me
It is possible when you installed the tube part (Or thru hull) pressure was not even and the tube got out of round. With uneven hull and bilge surfaces this is quite possible. The metal fitting would help but I would check and make sure your mounting surfaces are flat and parallel inside and out. A little tuning with a small grinder might fix the problem. It could also be a part defect or a heavy scratch inside the tube. Take a deep calming breath and look at it carefully. Hopefully a bit of adjusting will solve the problem. Good luck

MarkSF 05-06-2013 12:54 PM

Re: Raymarine ST40 speed transducer nearly sunk me
Is this the thru-hull that has a flap inside, to prevent most of the water entry while changing the plug?

Small chance this is the issue, but when Airmar changed the thru-hull for my DST800 transducer to include a flap, the transducer changed too. The new version is identified by a yellow O ring under the cap. Yellow O ring with flap, black O ring without flap.

Faster 05-06-2013 01:33 PM

Re: Raymarine ST40 speed transducer nearly sunk me
Damaged O-ring?? Not likely, I suppose if both plug and sensor leak...

KeelHaulin 05-06-2013 02:22 PM

Re: Raymarine ST40 speed transducer nearly sunk me
try removing the transducer and putting the plug in and see if that stops the leak. If not, then take the plug out and put the palm of your hand over the hole with moderate pressure and look for leaks on the sides of the fitting. If water is weeping out of the sidewall you know it's cracked.

When I installed mine I put a thick layer of Sikaflex on the flange and threads where the fitting goes through the hull. Then I loosely tightened it so the sikaflex would form a gasket between the fitting and the hull. Once set I then tightened the fitting further. If you did not use sealant I would suggest hauling the boat, removing the fitting and doing something similar.

Frogwatch 05-06-2013 02:50 PM

Re: Raymarine ST40 speed transducer nearly sunk me
Keep a can of plumbers putty aboard. It can be jammed into cracks from the outside in the water and used to seal sudden failed shaft seals etc. It does not harden stays flexy and seals till you can do something.
You do not need to be hauled, you need a diver to jam a wood plug up the opening and seal it with putty. Get rid of that silly knotlog thing.

saildork 05-06-2013 03:34 PM

Re: Raymarine ST40 speed transducer nearly sunk me
Did you put some of the gel supplied in the kit on the o-rings of the transducer and plug?

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