NASA log paddle wheel installation

[webcraft]

In light of our current ongoing experience I am interested in any issues others have had with their NASA through-hull paddle wheel logs.

If you have installed one of these using the NASA through-hull fitting, did you:

a) use silicon or PU sealant?

b) glass it in as per NASA's recommendation?

And

c) have you had any leaks or failures?

d) how long has it been in for?

- W

 

[Refueler]

First of all ... doesn't really matter which brand of unit - the through hull can be mounted same whatever ... I agree that the Nasa Clipper through hull tube flange has come in for some heavy criticism ... how many fail due to owners over-tightening and how many due to the weak joint ??

But I have fitted quite a few Nasa and Echopilot through hull paddle wheels and this is my preferred, this is only one of many ways and I do not say its better than another. I recently had a cracked paddle wheel log unit and when removing .. it hadn't been extracted for ???? how many years ... it was seized in. In twisting it to break the hold - the through hull tube just turned a fraction ... it was originally fitted with Marine Sealant as per usual practice. This resulted in a slow but steady leak..... about 2ltrs a day. That has now been remedied by :

a) First prepare the in and out areas that will take any bonding ... I use Oven Cleaner Foam ... this not only cleans but also removes any grease .. Once wiped away - fresh water wash the area and wipe away water. It does not have to be absolutely dry as I use PU Glue which uses moisture to cure.
b) Definitely not Silicon - especially in SW conditions ... I use Exterior Seawater Proof PU Glue as a 'filler' applied liberally to the tube and then put into place ... the tube then needs a further application on the inside with the hand nut then screwed down to 'squeeze' the PU glue outside and inside... making sure tube is fully home.
Then using a wet rag ... wipe away the excess outside and inside before it cures. If its already started foaming and cannot be wiped away ... then wait a bit and then use a kraft knife or box cutter to remove excess.
c) I have found that the best resin type to use for final sealing of various is where glass fibre has been mixed into the epoxy or polyester resin ... Devcon used to be an excellent product ... It is generally accepted that Epoxy based is best. Mix up a reasonable sized amount and then carefully spatula it round the fitting making sure it contacts fully the surround hull and the hand nut itself. I believe in making this a permanent seal and to remove would need grinding out.

Be careful not to have the epoxy mix too high ... you must leave plenty of threads left for the log and its securing nut.

Points to be aware of :

1. DO NOT overtighten the through hull tube .. only enough to have outer flange flush with outer hull and with a very thin layer of sealant acting as seal.
2. Make sure outer and inner are clean to accept the sealant and epoxy mix.


I know others will suggest alternative .. that's fine. Mine is only one of the many ways ......... so far I have not had any fitted as above leak or fail. But I did have one fail using Marine Sealant !! I even posted a thread about the lift out and work to solve .... that'll teach me not to listen to others and do my 'way ' !!

Good luck.

 

[webcraft]

First of all ... doesn't really matter which brand of unit - the through hull can be mounted same whatever ... I agree that the Nasa Clipper through hull tube flange has come in for some heavy criticism ... how many fail due to owners over-tightening and how many due to the weak joint ??

But I have fitted quite a few Nasa and Echopilot through hull paddle wheels and this is my preferred, this is only one of many ways and I do not say its better than another. I recently had a cracked paddle wheel log unit and when removing .. it hadn't been extracted for ???? how many years ... it was seized in. In twisting it to break the hold - the through hull tube just turned a fraction ... it was originally fitted with Marine Sealant as per usual practice. This resulted in a slow but steady leak..... about 2ltrs a day. That has now been remedied by :

a) First prepare the in and out areas that will take any bonding ... I use Oven Cleaner Foam ... this not only cleans but also removes any grease .. Once wiped away - fresh water wash the area and wipe away water. It does not have to be absolutely dry as I use PU Glue which uses moisture to cure.
b) Definitely not Silicon - especially in SW conditions ... I use Exterior Seawater Proof PU Glue as a 'filler' applied liberally to the tube and then put into place ... the tube then needs a further application on the inside with the hand nut then screwed down to 'squeeze' the PU glue outside and inside... making sure tube is fully home.
Then using a wet rag ... wipe away the excess outside and inside before it cures. If its already started foaming and cannot be wiped away ... then wait a bit and then use a kraft knife or box cutter to remove excess.
c) I have found that the best resin type to use for final sealing of various is where glass fibre has been mixed into the epoxy or polyester resin ... Devcon used to be an excellent product ... It is generally accepted that Epoxy based is best. Mix up a reasonable sized amount and then carefully spatula it round the fitting making sure it contacts fully the surround hull and the hand nut itself. I believe in making this a permanent seal and to remove would need grinding out.

Be careful not to have the epoxy mix too high ... you must leave plenty of threads left for the log and its securing nut.

Points to be aware of :

1. DO NOT overtighten the through hull tube .. only enough to have outer flange flush with outer hull and with a very thin layer of sealant acting as seal.
2. Make sure outer and inner are clean to accept the sealant and epoxy mix.


I know others will suggest alternative .. that's fine. Mine is only one of the many ways ......... so far I have not had any fitted as above leak or fail. But I did have one fail using Marine Sealant !! I even posted a thread about the lift out and work to solve .... that'll teach me not to listen to others and do my 'way ' !!

Good luck.

Refueler, thanks. A link to the thread about the failed unit would be appreciated.

What is PU glue? Is there a brand name?

- W

 

[ghostlymoron]

I recommend following the instructions from NASA including the use of silicone sealant in contact with the plastic components and glassing in the securing but for extra strength.
I must admit to not having done either on my first installation but after hearing a club member's account of his failing on a passage to the outer Hebrides, I glassed it in on my then current boat. It was fairly easy to do by cutting 4 discs of mat with a cross cut in the middle and slipping them over the log holder.

 

[Refueler]

Ok the thread is :

Leaking Log through hull

You will note that I used Epoxy Putty as the sealant and not PU .... this was because I needed to lift boat back in that afternoon and could not wait for PU to cure.

PU ..... PolyUrethane glue. It comes in two grades ........... white interior and brown exterior.

A well known brand name is Gorilla Glue.

We have GG but exact same product in a more generic label is by Bison ... and you get a much larger bottle for a lot less money !!

PU glue can be mixed with a bit of water to create a foaming light weight filler. can be sanded .. carved ... drilled ....

Because its Seawater proof - I use it where sealing is needed .... amazing stuff.

 

[Kwik Decision]

If you have installed one of these using the NASA through-hull fitting, did you:

a) use silicon or PU sealant?

b) glass it in as per NASA's recommendation?

And

c) have you had any leaks or failures?

d) how long has it been in for?

I fitted one in our previous boat, a Sadler 29, in 2011 or 2012. I followed the instructions and used silicon sealant, however on fitting, with the silicon "wet" I did the internal nut up quite loosely initially, so as not to squeeze all the silicon out. The following day, once the silicon had gone off and created a gasket between the skin fitting flange and hull, I tightened it up some more. I then glassed it in on the inside. It never leaked, and as a friend bought the boat, I know it is still fine now.

 

[prv]

First of all ... doesn't really matter which brand of unit - the through hull can be mounted same whatever

Most of them can, because they’re the same Airmar range of parts whichever instrument brand they’re sold as. NASA ones have very different installation instructions, though.

Fibreglassing the thing into the hull seems to me like a bodge that shouldn’t be necessary. We don’t generally do it with other kinds of through-hull fittings.

Pete

 

[LittleSister]

I have never installed one, as far as I can remember, but I have had a NASA log thru-hull in a boat. It was in the boat when I bought it, was still there 10 or so years later, and never gave me any problem or concern. (With the latter, perhaps ignorance is bliss?) As far as I can recall it was not glassed in.

I find it hard to believe that the skin fitting would break unless knocked or pulled about in some way. On the boat I had the log was in the most easily accessible locker in the boat, which we were keen to use for day-to-day food storage. Because of the risk of things being thrown about with boat movement and potentially putting sideways pressure on the log tube, we made a wooden cover to fit over and protect it. This could just be lifted off, but couldn't be pushed sideways. I installed this protection not because I had any particular concerns about the NASA fitting, but would be concerned as a matter of course to avoid any such tall fitting being knocked about.

On other fittings on boats I have made protective bulkheads or covers, or ensured that the storage around was used for soft, lightweight stores, such as cushions or toilet/kitchen rolls.

I can't think what purpose glassing the fitting in would serve, except as an alternative to such protection.

 

[webcraft]

I have never installed one, as far as I can remember, but I have had a NASA log thru-hull in a boat. It was in the boat when I bought it, was still there 10 or so years later, and never gave me any problem or concern. (With the latter, perhaps ignorance is bliss?) As far as I can recall it was not glassed in.

I find it hard to believe that the skin fitting would break unless knocked or pulled about in some way. On the boat I had the log was in the most easily accessible locker in the boat, which we were keen to use for day-to-day food storage. Because of the risk of things being thrown about with boat movement and potentially putting sideways pressure on the log tube, we made a wooden cover to fit over and protect it. This could just be lifted off, but couldn't be pushed sideways. I installed this protection not because I had any particular concerns about the NASA fitting, but would be concerned as a matter of course to avoid any such tall fitting being knocked about.

On other fittings on boats I have made protective bulkheads or covers, or ensured that the storage around was used for soft, lightweight stores, such as cushions or toilet/kitchen rolls.

I can't think what purpose glassing the fitting in would serve, except as an alternative to such protection.

I believe the glassing in is to stop the tube pulling out of the hull if the outer flange fails.

Was discussing this with a friend who works on boats for a living.

Silicone takes 24 hours to cure, so a haul out would be mandatory.

If we use PU sealant the job can be done against a wall between tides. Then we glass the thing in. So even if the PU eats NASA's crappy plastic the thing doesn't fall out. And I doubt it is going to eat it in two or three years.

Then in two or three years time or whenever the boat has to come out of the water I will replace it again at my leisure, using silicone.

Make sense?

- W

 

[dankilb]

I’ve actually got a new one on the bench at home - so took an additional interest in the leak thread…!

And after what I read in that one, I’m planning to epoxy the skin fitting (so no sealant) and then modestly glass the lot inside (again with epoxy).

I’ve also got dozens of TruDesign bits and so was able to compare like-for-like. I wouldn’t say the Nasa fitting is ‘shockingly’ flimsy in comparison. But, if it can’t handle anything other than silicone by their own admission, and seeing as we’re committing to the brand/design of log (going electromagnetic), I rationalise that I may as well make it part of the hull.

I should add that we’re mid- major refit so no shortage of glass, epoxy or mess-making. If it meant grinding and glassing in my pristine boat, I may well revert to the silicone (or another brand - but for the money, that wouldn’t work for an EM log).

 

[Refueler]

I believe the glassing in is to stop the tube pulling out of the hull if the outer flange fails.

Was discussing this with a friend who works on boats for a living.

Silicone takes 24 hours to cure, so a haul out would be mandatory.

If we use PU sealant the job can be done against a wall between tides. Then we glass the thing in. So even if the PU eats NASA's crappy plastic the thing doesn't fall out. And I doubt it is going to eat it in two or three years.

Then in two or three years time or whenever the boat has to come out of the water I will replace it again at my leisure, using silicone.

Make sense?

- W

General use PU sets up in 1 hour but continues to cure for approx 24hrs. Basically you can handle joints after 1 hour but not put stress on it for at least a few more hours.

PU would work between tides as long as you can give at least 2 - 3hrs before its immersed.

PU will not eat Nasa's tube ..... it hasn't on any gear I've used the combo.

Personally - if you are going to work between tides - then I would consider the Epoxy Putty sticks you can buy for sealing exhausts / metal holes etc. To do similar to what I did when I had only a short time between lifts. The putty will not only create a full seal and lock the tube in place - but be secure in the event flange did detach. Use of PU inside to finish the job ..

For "LittleSister" the point of glassing in is to provide safety and security should the outer flange detach.

I've compared Nasa's fitting to others and it does have a slightly thinner joint flange to tube ... but I tend to think that installers may in many cases over-tighten .. causing it to weaken or crack.

 

[Dan Tribe]

In light of our current ongoing experience I am interested in any issues others have had with their NASA through-hull paddle wheel logs.

If you have installed one of these using the NASA through-hull fitting, did you:

a) use silicon or PU sealant?

b) glass it in as per NASA's recommendation?

And

c) have you had any leaks or failures?

d) how long has it been in for?

- W

My first one I fitted just using marine silicone, doing the nut hand tight. I knew better than the manufacturers so never bothered to follow the instructions. After about 2 years it snapped of in my hand while cleaning the impellor. Luckily I had a wooden plug nearby but it concentrates your mind when you can see light through the bottom of your boat!
The second one I glassed in just like it said in the installation mamual. This lasted about 15 years until I decided that I didn't really need a log anyway, and removed it. Perhaps the manufacturers do know what they are talking about?

 

[pvb]

Perhaps the manufacturers do know what they are talking about?

They do! Using anything other than silicone sealant on a Nasa fitting isn't wise.

 

[Refueler]

They do! Using anything other than silicone sealant on a Nasa fitting isn't wise.

I think he actually was referring to the 'glassing in' which he had elected not to do first time round.

 

[pvb]

Manufacturers' instructions are generally provided to help people install stuff in a way which will lead to optimum longevity and minimal problems. Nasa's specific instructions to use only silicone sealant and to reinforce the installation with GRP obviously fit this description. Naturally, some people ignore them, but may experience problems.

 

[Alfie168]

I fitted one in our previous boat, a Sadler 29, in 2011 or 2012. I followed the instructions and used silicon sealant, however on fitting, with the silicon "wet" I did the internal nut up quite loosely initially, so as not to squeeze all the silicon out. The following day, once the silicon had gone off and created a gasket between the skin fitting flange and hull, I tightened it up some more. I then glassed it in on the inside. It never leaked, and as a friend bought the boat, I know it is still fine now.

Thats pretty well how I did mine and glassed it in with car body glass fibre paste (not filler) on the inside. I use silicone grease on the sender unit to ensure you can get it out. I recently replaced a log wheel that had burst due to seawater ingress which had corroded the iron core and the rusting had burst through the plastic. It was a very easy push out the spindle and push in the new one job, but always be careful and don't force things. No leaks so far after 14 years or so.

 

[Refueler]

Manufacturers' instructions are generally provided to help people install stuff in a way which will lead to optimum longevity and minimal problems. Nasa's specific instructions to use only silicone sealant and to reinforce the installation with GRP obviously fit this description. Naturally, some people ignore them, but may experience problems.

Also to cover their **** and for warranty purposes.

 

[pvb]

Also to cover their **** and for warranty purposes.

Absolutely right. They don't want numpties using PU instead of silicone sealant and then trying to make a warranty claim if the thing cracks.

 

[webcraft]

Manufacturers' instructions are generally provided to help people install stuff in a way which will lead to optimum longevity and minimal problems. Nasa's specific instructions to use only silicone sealant and to reinforce the installation with GRP obviously fit this description. Naturally, some people ignore them, but may experience problems.

I've just launched the boat after a few unexpected bills. Cheaper to use PU now, avoid a lift-out and redo it with silicon at my leisure in two or three years when she comes out of the water again. I will be glassing it in though, just in case the PU eats the plastic. I think I will be OK for three years, don''t you?

- W

 

[Refueler]

Thats pretty well how I did mine and glassed it in with car body glass fibre paste (not filler) on the inside. I use silicone grease on the sender unit to ensure you can get it out. I recently replaced a log wheel that had burst due to seawater ingress which had corroded the iron core and the rusting had burst through the plastic. It was a very easy push out the spindle and push in the new one job, but always be careful and don't force things. No leaks so far after 14 years or so.

The sender unit on mine had seized in the tube and that 'broke' recc'd Marine Sealant seal when twisting sender to remove ..... leading to lifting the boat out and having to sort out with a work time of ~2hrs .......

If I decide to fit the Nasa Dual Clipper unit and its senders - the hull tube will need changing .. My own preferred way as described earlier has proven itself when not only fitting my own gear on previous boats - but also when I've installed on friends boats ....

As I said - its only one of many ways .....

As regards plastics .... Nasa ... Echopilot and others - the plastics - many chemical forms do not like any sealants with Ketone ... Acetone ... in fact most xxxxTONE chemicals - which are used as solvent carriers in the sealant.

Just pointing out a bit of info .... PU glue is free of such .. in fact Bison PU Glue as I showed earlier states on the Label - Safe for Plastics....