Plastic log fittings

[DanTribe]

Whilst sanding the boats bottom, the external flange to the NASA log skin fitting fell off [honest guv it just came off in my hand].This left just a thin bead of mastic holding the water out.Have I just been unlucky or has anyone else had problems with these fittings? Is there a more robust alternative to the standard plastic skin fitting?
The unit is less than 3 years old

Dan

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[colvic]

Hi Dan

You may have read a bit on the forum last year about Golden Dawn which almost went down due to the failure of the NASA through hull plastic log fitting.

We were a little way out from Barcelona and didn't notice what had happened until the engine stalled due to water going into air intake. When the unit fails it leaves a hole larger than any of the wooden plugs in the standard kit.

Anyway, with the help of the Guardia Civil launch we got into the marina and everything is now great. NASA charged me £5+ for a new housing and told me and I quote "have only heard of a couple of failures and these, we think, we due to incorrect installation".

Make sure you clean the inside of the hull down to bare GRP and then build up a good strong fillet round and up the fitting.


Phil

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[Guest]

Usually NASA are one of the better Customer ....

Service outfits ..... I always had good service and after care from them.

If you don't like the NASA fitting - go for another company's such as Seafarer - you can find same diameter in various manufacturers kit .....



<hr width=100% size=1>Nigel ...
Bilge Keelers get up further ! I only came - cos they said there was FREE Guinness !

 

[dickh]

When you replace it, don't tighten up too much and make sure it's not a tight fit in the hole. Alternatively other manufacturers sell Bronze ones(Raymarine), suitable for wooden boats, which will probably work with the Nasa - you'll have to check with Nasa though...

<hr width=100% size=1>dickh
I'd rather be sailing... /forums/images/icons/smile.gif

 

[oldsaltoz]

G'day Dan,

There is a manufacturer that supplies these plastic fittings with a high fibre content, much stronger and less prone to cracking.

Most important that plastic fittings are well seated and not too tight: I find a coat of closed cell balloons and epoxy good for this, lay some glad wrap over the wet cells and do the fitting up finger tight, wipe away any excess inside and out and re-retighten the next day (About half a turn)

Hope this helps

Andavagoodweekend. Old Salt Oz /forums/images/icons/cool.gif

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[steve_cronin]

Did it have a wooden backing pad?

Ours did on a Newbridge Venturer around thirteen years ago. We were luckily in the Poole entrance channel so when the impellor unit just came off we were able to stuff tea towels into the hole, switch on the electric and man the hand pump and make for Sandbanks Yacht Co where we dried out against their jetty . It appeared that either bilge water or a small crack in the flange developed and soaked the 18mm ply pad swelling it, which was too much for the plastic flange to resist. That too was a NASA unit

Tufnol pads are much safer and are almost universal now with volume builders.

Stev CRonin

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[tristan]

Mine did it too and fell out out completely (i had the plug in at the time). I had to quickley make a water tight compartment with wood, sikaflex and gaffa tape, and then wait for high tide until i could dry out to replace it; 4.00 in the morning (never a suitable time)!!

The unit is 24 years old though, so i'm not complaining too much, though i will say that i've never heard of other manufacturers fittings failing like this - i suppose you just get what you pay for!?!

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[Avocet]

I sometimes worry about this. I have a NASA log and I thought long and hard about whether I should put a wooden backing pad on it. I decided against it because I was worried about the wood getting damp and swelling. I'm glad I didn't! That said, I think Nylon also absorbs water and swells a little. This might be enough to crack the housing if it was a bit on the tight side in the first place. I bedded mine down with Sikaflex and it's been OK for the last 4 seasons...

The worst thing is that I don't think there's any non-destructive way of testing them.

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[DanTribe]

Thanks

Ta very much for all your comments. I am lucky that this happenned whilst out of the water.The stories of the failures at sea are nightmares, suppose it happenned while the boat was unattended!
I can't fault Nasa's customer service, a new fitting was dispatched immediately.Not surprisingly they don't recommend any other manufacturers products over their own.
I shall take on board all your comments when refitting, although I'm not sure about Old Salt's advice to "gladwrap my wet cells",that sounds a bit pervy.Hey don't knock it 'til you've tried it.
Thanks to all.
Dan

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