Thru Hull Questions

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wegcagle
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Thru Hull Questions

Post by wegcagle » Wed Feb 17, 2010 3:25 pm

I'm looking a thru-hull fitting for under the waterline for my GV-15. I was going to use a hose type connection, but it appears that's against ABYC standards. It seems like I should use a pipe type connection.

1. Is this correct??
2. If I use the pipe type connection, then can I still use stainless steel thru hull and connect to a PVC pipe???
3. If I can do the above, then I assume there's a specific type of adhesive that I need to be on the look out for???

Thanks, I didn't know all of this until I was reading today. I guess better now than a few years down the line when the hose connection fails :help: :help: :help:

Thanks,

Will


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Re: Thru Hull Questions

Post by tech_support » Wed Feb 17, 2010 3:33 pm

what ABYC standard are you looking at?

what type/size of thru hull and where on the boat?

Not until you get to bigger boats and bigger through hulls would you need a sea cock fitting

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Re: Thru Hull Questions

Post by jacquesmm » Wed Feb 17, 2010 3:35 pm

I don't know what a hose tru-hull would be. Do you mean a tru-hull connected directly to a hose? That is done all over.
It is always safer to to have a valve but on a small boat, I wouldn't worry.
On a large boat, a valve is a must.
I know and follow the ABYC standards but I am confused about the question.
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Re: Thru Hull Questions

Post by wegcagle » Wed Feb 17, 2010 4:08 pm

ABYC standards section H-27 Seacocks, Thru-Hull Fittings, and Drain plugs. This section states that "Thru-hulls with hose attachment (like the one below) are not recommended for below the waterline applications."

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On my GV15 my drain pipes from my livewell run to a common drain out the port side transom, but in order to make sure the terminal drain in the transom was lower than my live well I had to make the hole about 1/2 above and 1/2 below the waterline. So I wanted to put in a stainless steel thru-hull with a hose attachment there but they all stated "not for below the waterline applications" so I got scared and read the ABYC standards on it, and now I'm even more confused :doh: Thanks for your help guys.

Will
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Re: Thru Hull Questions

Post by jacquesmm » Wed Feb 17, 2010 4:26 pm

OK, it's a recommendation, not a rule but I would follow it.
What it means is that barbed tru-hulls are not recommended, tru-hulls with a valve are preferred.
Those barbed things are not really tru-hulls. They are made for drains.

In your case, it's just a drain and from what you describe, it ends in a closed compartment, behind the motorwell bulkhead.
It is not a big problem but a tru-hull with a valve doesn't cost much more.
I would use a correct tru-hull, one with a valve, it's safer.
Think also of the resale value of the boat. A surveyor may give it a bad note if he sees that below the waterline.
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Re: Thru Hull Questions

Post by TomW » Wed Feb 17, 2010 4:48 pm

Will I'm a little confused about what your asking. Is this for your tank fill? Then an underwater take up must have a valve at where it comes into the boat and a pipe thread is the way to go so the shut off valve sets directly on the intake. Here are the valves you need to use as close to intake as possible or at the intake. http://www.discountmarinesupplies.com/c ... hild=71477

Using pipe thread for an intake isn't a good idea. It's fine for drains and outlets. Just use the proper size flexible pipe and clamp it to it. If you think you might have some back up route the pipe higher than the outlet at some point as long as it's lower than the inlet to the drain. Or put a flapper on it.

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Re: Thru Hull Questions

Post by Cracker Larry » Wed Feb 17, 2010 5:19 pm

This section states that "Thru-hulls with hose attachment (like the one below) are not recommended for below the waterline applications."


That's because you can't screw a shut off valve (sea cock) on to it. I agree with Jacques all the way. Do it right :wink:
Using pipe thread for an intake isn't a good idea.
:doh: Actually pipe thread is the only thing that is approved for below the waterline intakes or drains. Will's is a drain, not an intake though, but drains below the waterline should also have a seacock, and you need pipe thread to screw the seacock directly onto.

If it was mine, I'd use a bronze thru-hull fitting and a marelon sea cock. Unless you just like the bling of stainless :D
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Re: Thru Hull Questions

Post by wegcagle » Wed Feb 17, 2010 5:28 pm

C.L. It is the bling of the stainless that I like. 8) So now my question is this.

1. Threaded thru-hull to a seacock. Done deal. If I wasn't in to the whole doing it right thing. I would have used cheap A$$ parts, and done a have A$$ build :lol: (Guess this really wasn't a question :D )

2. Can I place a treaded stainless thru-hull to a marelon sea cock? If I can what kind of adhesive do I need between the thread?.

3. Can I connect my drainage hose to the seacock? Or do I need to run PVC the whole way?

Thanks
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Re: Thru Hull Questions

Post by TomW » Wed Feb 17, 2010 5:49 pm

Can I place a treaded stainless thru-hull to a marelon sea cock? If I can what kind of adhesive do I need between the thread?.
No adhesives please, use nylon pipe tape so you can take it apart if you need to.
Can I connect my drainage hose to the seacock?
Yes use a thread to pipe adapter, available at Lowes or HD, I like to use Schedule 80 if available as they are stronger but Schedule 40 is fine. Again nylon pipe tape on the threads to the seacock.

Tom
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Re: Thru Hull Questions

Post by wegcagle » Wed Feb 17, 2010 5:57 pm

Okay, so pictures being worth a 1000 words.

This......
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Plus....
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Plus...
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Using nylon pipe tape. This would be the best, strongest, safest.....insert good words here, way to do it. Correct???

Thanks,

Will
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GV15, D4 done! Dreaming about the next one

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