Thru hull spacer material

[rsimon]

The plan is to install this male threaded thru hull onto a 90 deg. female elbow fitting so as to bring a hard line assembly up above the water line. My hull thickness (the sides of the hull) is 1/8". The securing nut only goes up so far onto the threads leaving a good 1/4" space left...I won't be able to tighten it up against the hull from the inside. I was considering using a hardwood or even aluminum for a spacer to act as sort of like a washer. Any ideas?
I hope this these pics help:

http://i1216.photobucket.com/albums/...s/2e3725a2.jpg
http://i1216.photobucket.com/albums/...s/193b08c6.jpg
http://i1216.photobucket.com/albums/...s/32b62681.jpg

[anthony goodson]

Good morning
Here in the UK we would go to a plumber's merchants and buy some thick neoprene or rubber washers.

[hoytedow]

Check standard garden hose washer for size. It looks like it may be close. You may need 2 to get it thick enough.

[rsimon]

The Maeleron fitting is bigger (diam.) than garden hose washers. Also, it has to absolutely water tight (over time as well.) I was thinking of something harder like a plate of aluminum or some sort of composite wood to in effect shim the hull make it artificially thicker than the 1/8" it is. Maybe IF I found the right diam. rubber washer that fit tight around the mushroom/fitting end without any gaps(leaks) I could stack those washers to take up the space. Can I use 5200 over rubber? Responses are appreciated. Rog

[anthony goodson]

It doesn't need to be that tight on the mushroom fitting ,it seals on the flat surfaces.

[Frosty]

Are you wanting some material to just seal the gap or something as a backing plate the strengthen the very thin 1/8th hull.

A hull strengthening backing plate of some sorts would be used by a professional builder on such an application like marine ply wood epoxied on.

[gonzo]

You need to use a bedding compound rated for underwater use. Also, the threads don't go to the end because there is a backing plate required on the inside if the hull is so thin. Otherwise, it will end up leaking and the hull may fail too.

[rsimon]

That's my question, what would you use as a backing plate: wood or composite plastic or aluminum? (my hull is 1/8" aluminum.) Is 5200 rated for underwater use?

[gonzo]

Yes 5200 will do fine Aluminum would work. Make sure you put 5200 between the backing plate and the hull too.

[rsimon]

Thanks, I was leaning towards going with the aluminum spacer as a back plate for that. I will take your advice with the 5200 between the spacer and hull too.