underwater (salt) powdered glue

[chuckg5]

In my off hours I have a 30,000 lb sailboat down here in Florida. The transducer now leaks around the caulks. I've tried fine sawdust for the last 6 months trick but its tempory. Is there an underwater powder glue that might suck in from the outside and set up to seal the leak?
Thank you.
chuck

 

[unclesyd]

Have you tried wood flour instead of sawdust, a little tricky to handle underwater but it works a lot better.

Have you looked at the underwater caulks and epoxies?

 

[chuckg5]

No, unclesyd. I haven't heard of 'wood flour'. sounds like a finer powder than sawdust. I have to go diving down on the transducer about every 4 months to reapply the sawdust trick. I then squeese two part expoxy putty together and apply a ribbon around the transducer block. still only works for about 4 months then starts to leak again. going down this week to reapply. Is 'wood flour' sold at home depot or ace hardware stores?
Thank you for the reply
chuck

 

[unclesyd]

It is a filler and thickener for epoxy systems. You should be able to get it from a marine supply store that carries epoxy or polyester systems.
Is your epoxy system specifically recommended for underwater application?

Look at the underwater caulks.

Does your transducer have treaded section on the part that protrudes through the hull?

Is this a single hull?

I've used several materials, the aforementioned wood flour, beeswax + beef tallow with metallic fillers, and tripled boiled linseed oil + red lead, prior to the advent of underwater systems to stop leaks at thru the hull fittings.

 

[chuckg5]

Is the 'wood flour' from west marine a wood product?
One reason I use sawdust is, I put it in a sandwich bag,dry then dive below and place the open bag around the transducer. as the sawdust is sucked in, hopefully it embeds and expands as it soaks up water. It works but temporarly. the underwater expoxy putty is put around the outside block but its covered with heavy anti foul paint and does not stick that well.
Many thanks
chuck

 

[unclesyd]

Yes it's a product made from wood.

What does the inside of the hull look like where the penetration for the transducer shaft look like?

Is there any room to drive a little waxed packing between the hull and the transducer shaft?

It sounds like this has been going on for awhile, how long before you pull the boat so you can make a proper fix?

The reason I asked about if the inside part of the transducer is threaded and if threaded you could make a large nut and use a soft gasket to seal the inside.

 

[chuckg5]

unclesyd
It'll be another year before I pay to pull the boat out to repaint and fix the transducer. the hull is 3/4" fiberglass and I put the transducer in tight, with
4200 glue all around and tightened down on the transducer nut on the inside. year later it started to leak maybe after some pounding out on the high seas. no room for wax packing at all. maybe that wood flour will swell up inside and stop it a little longer.
Thank you for the suggestion, I'll go for and let you know.
chuck