Nasa thru hull

dolabriform

dolabriform

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freewheeling.world
HI all

Got to the boat yesterday to find water 6 inches deep inside :(

After bailing out we discovered that it was coming in through the log impeller through hull which was recently replaced. Lifted
out and the through hull appears to have failed so off to buy a new one today.

Hopefully can get it swapped out this morning and then get launched again ready for the high tide at 3.

I've never had one fail before, anything I should look out for?
 
On my old boat I had a NASA through hull for five years, never a drop of water leaked through it.

How did if fail?
 
They are prone to fail. Nasa advise that the through hull fitting is glassed in which is what I've done with mine.
 
I've had two of these plastic through-hull fittings break (a crack between flange and the nut); one professionally fitted, the other by myself.

On both boats I did the decent thing and had the hole glassed up. No regrets. If you want the log to still read then glass it up and use one of the little black boxes that take your speed from your boat's GPS and convert it into pulses your log instrument can read. (no, not lentils or split peas, silly!)

I'm sure someone will soon be along with a name of the co. that sells them. About GBP 110 each IIRC.
 
dolabriform said:
I've never had one fail before, anything I should look out for?
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Do not use Sikaflex, etc, to seal it - only use ordinary bathroom silicone sealant. And cover the inside with fibreglass, as recommended in the installation instructions.

It's typical Nasa quality though, and a common failure. You'd have thought by now that Nasa would have changed the spec to use proper plastic rather than the frail stuff they use.
 
I think it was put in with sika 2912. It came apart in my hands. The yard have just fitted a new one with sika 2911, and not glassed in. Getting worried now
 
I have had 2 of these fail, the second could have sunk the boat but for the glassfibre around the nut & threads as when I removed the GRP water started to really flood in. Glassed the hole up completely and now no worries. It is appalling that a safety critical fitting is made from such flimsy plastic-both of mine developed cracks despite great care tightening the nuts and using bathroom sealer. I cannot believe after the first failure I bought another!
 
They should be regarded as formers only. They should be glassed in. NASA tell you to glass them in, there's even a diagram in the instructions telling you how to glass them in.
 
dolabriform said:
I think it was put in with sika 2912. It came apart in my hands. The yard have just fitted a new one with sika 2911, and not glassed in. Getting worried now
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Mine's been in over 20 years now. Before I knew any better I 'glassed' it in with some Plastic Padding from Halfords. Later, I added another thick layer of West System epoxy plus woven glass fabric. It won't fail immediately so get yourself some woven glass and a West Epoxy kit and do it when you next have the opportunity. It doesn't have to look pretty, just strong.
 
Thanks all, despite what the yard say I will be glassing it in at the earliest opportunity!

Made it round to shotley yesterday, and now loving this glorious sunshine :)
 
Dan Tribe said:
They should be regarded as formers only. They should be glassed in. NASA tell you to glass them in, there's even a diagram in the instructions telling you how to glass them in.
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NASA are the only type with this requirement, though, because all the other common ones are properly made in the first place. So it's not that surprising that the OP's boatyard didn't cover his log transducer with GRP as a matter of course.

Pete
 
prv said:
NASA are the only type with this requirement, though, because all the other common ones are properly made in the first place. So it's not that surprising that the OP's boatyard didn't cover his log transducer with GRP as a matter of course.

Pete
Click to expand...

What I'm finding shocking is that even when I showed them the instructions they disagreed with me. I"m going to talk to my insurance company today, as having paid for a lift out and the fitting of the original, and now the yard saying that it's the manufacturers fault that it failed even though they didn't install it to manufacturers instructions, I"m not very happy :(
 
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