nasa depth sensor - how to attach to hull

[Cappen Boidseye]

I have just bought a nasa clipper duet, the depth sensor can be attached to the inside of the hull. What is the best way to do this? bearing in mind that one day it might need to be replaced.
Also. how close to vertical does it have to be? there aren't many flat bits on a grp yacht hull.

 

[Tin Tin]

I have just bought a nasa clipper duet, the depth sensor can be attached to the inside of the hull. What is the best way to do this? bearing in mind that one day it might need to be replaced.
Also. how close to vertical does it have to be? there aren't many flat bits on a grp yacht hull.

Easiest, best and cheapest way

 

[nmeyrick]

Afraid I'd have to disagree with that - I bought a replacement transducer for my NASA clipper last year afer the original, which is through hull, packed in.

I spent a full glorious sunny day buried in the bilge trimming the pipe to fit the curve of the bilge, adding filler and later supplementing this with a layer of silicone sealant when i just could not get it to stop leaking oil.

In the end I followed a tip from here and but a generous dollop of silicone sealant in the bilge, then slowly pushed the transducer in whilst twisting which I was told avoids trapping air. It has worked perfectly since, for a total fitting time of about 5 mins once I'd given up with the proper kit.

Not saying that the kit doesnt work but It can be fiddly; silicone was quick and easy

 

[Cappen Boidseye]

I like the silicon blob idea, I think that will be my first try. Any thoughts on how vertical is vertical enough? I can't think of any bit of hull which is 'flat'

 

[VicS]

The above mentioned kit.!

See also the instructions below from many years ago for a Seafarer transducer. I did mine like this 33 years ago. Still there, no leaks, no problems. Do it properly... and do it only once!

Done with some filler to fix it in place then with resin and glass mat. Bodging with filler + silicone is bound to fail

The alternative is straight onto a dollop of sealant..Silicone if you want to be able to remove it again faily easily ... Sikaflex for a near permanent fixing.

Make sure there are no trapped air bubbles.

 

[nmeyrick]

Thanks Vic, that looks like a good installation and makes sense. The instructions that came with the fixing kit made no mention of fixing it in place with resin and glass but said that the tube of filler included was all you need. I agree this doesn't sound very secure!

Given plenty of time I would think seriously about that approach but still think that the dollop technique scores well on efficiency if not elegance.

As to how flat, as you can see from the picture it doesn't need to be totally flat, just get as good as you can. And ensure the transducer is vertical not flat against the side of the hull

 

[grafozz]

I used a 100mm length of white 50mm Halyard marine hose and the transducer was a snug fit inside it .
Either epoxy or PU sealant to bond it to the hull , cheap and easy . When its set just half fill with , olive oil , but ensure that there is no air trapped inside the hose when pushing in the transducer , just push it in very slowly and carefully .

 

[PCUK]

Stick it vertically on a blob of body filler. Works fine!

 

[GrahamM376]

Stick it vertically on a blob of body filler. Works fine!

Agreed, that's how mine is and it works fine.

 

[Cappen Boidseye]

thanks to all, food for fort!

 

[Caer Urfa]

. What is the best way to do this? bearing in mind that one day it might need to be replaced.
Also. how close to vertical does it have to be? there aren't many flat bits on a grp yacht hull.

Fitted one years ago and still works fine.

Do not fit it close (or over) the keel !
To find the best spot I first pushed the sender into 'Blue Tack' and tested it in one or two places, out of the way, but , accessible in future.

Scrape off any paint on the bilge local to the mounting spot.

Once you have the best spot I used Sikaflex between the hull and the sender, you can then angle it so it is looking straight 'down'.

As already said above as you mount it in the sikaflex turn it a bit to remove any trapped air bubbles.

I proped it in position to set, then built up with Sikaflex around the outside of the sender for more support.

Never touched it since and it works great.

Hope this helps
Mike

 

[simonfraser]

mine's still in place and working with a blob of silicone 6 yrs later . . . .

 

[catalac08]

Do not use epoxy for this-when I removed my old transducer which was firmly bedded in a blob of epoxy I pulled a lump of the hull laminate away and then spent an unhappy few hours preparing and laminating a patch in and over the hole!

 

[VicS]

Do not use epoxy for this-when I removed my old transducer which was firmly bedded in a blob of epoxy I pulled a lump of the hull laminate away and then spent an unhappy few hours preparing and laminating a patch in and over the hole!

There was many years ago one brand of ES that had a small rectangular transducer for which the instructions were to epoxy in position!
I think the idea was that you did not remove it. If defunct you cut the lead and left it there ( it may have been very old whirly type Nasa ones)

 

[zambant]

Plasicine

I always use plasticine inside the boat - the stuff that GRP laminators use.

Clean hull inside well - warm the stuff up then press the stuff onto hull and press transducer in. Has never come off yet....

John