Thru-hull backing

CEShawn

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I just was wondering what people like to use to back their thruhulls.

I've seen everything from teak, starboard and composites.

I guess there was an old timers bit of using wood, so it would absorb water if it ever leaked but I do wonder about that theory if your using hardwoods. I would also wonder if it would put to much pressure on the fitting if it did expand.

The more I use starboard on projects the less I like it. I know it lasts great in the bilge as I use it for a L-shape stand in my boat. I just do not like the compress-ability of it which I think is a little important in this situation.

I just know sometimes teak is hard to come by in the size I need for some sea valves.

Just getting ready to maybe changing up a few things this winter.
 

El Mar

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Pedlyr

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My Shamrock has hatch covers for the fuel tanks that are secured with self-tappers. On previous boats I've owned, I used Starboard/HDPE strips as backing for these screws as they can strip the fiberglass easily.

On my most recent Shamrock work-in-progress I used strips of Azak left over from my house remodeling because they seem a little softer for a better bite. Don't need much of a pilot hole. I used gorilla glue as well because it foams up and expands. Did that on the small screws to hold the strips in place on the underside. Then LifeCaulk topsides. I know some have also used Trex style synthetic wood here as well.

Azak also seems to take LifeCaulk or bedding compound much better than HDPE. Although, I made a fairing block for my Airmar transducer out of HDPE and it has been fine for 3 years now. This summer, I installed a basic round fathometer 'ducer on my Dad's sailboat. I used a piece of Azak for a backer instead. Used a 1" piece and gave it a 3/4" over diameter. Caulk and then the nut. Seemed to work well.

Only thing I don't like about the Azak is that the cut ends show a grain. This grain can hold mold and dirt. A little sanding helps here.
 

tomy

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I'm bringing this item back up because I'm hauling out to do some projects on boat. one project is installing a new through hull fitting for bait well pick up. (old install by previous owner is always gettin airbound)
Question is...anyone know or premaid fairing block manufacture? See fiberglass is recomended over wood. any help will be appreciated. thanks. Tom
 
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