Depth sounder temporary fix

[ajames]

My depth sounder (in Hull mount in castor oil) stopped working, on inspection the tube holding the transducer and castor oil had come loose and all the castor oil had come out. As we were navigating a river channel with less than a meter below the keel I didn't have much time to do a proper repair so I used a large blob of sikaflex to attach it. My question is, although it seems to be reading the depth fine now, will it be ok to leave like that, or should I look to reinstate the tube?

 

[salar]

One school of thought is "If it ain't broke don't fix it" and you will probably have a job to remove it from Sikaflex. However, the transducer has a shiny plastic face so it will probably choose its moment come adrift again and I can cast iron guarantee that will be the moment you are totally relying on it. If it was mine I would reinstate the tube, and if that happened again and the leak was tiny I would simply add more liquid to get out of trouble then fix the leak later. We have had this debate on another thread but I would use water with antifreeze rather than caster oil but both work. Oil is more hassle to clean up if you need to add another fillet of Sikaflex to bond tube to hull.

 

[Graham376]

Ours has been stuck down with a blob of green GRP repair stuff out of a tube for 10+ years, works fine.

 

[Yngmar]

As mid-season fix, we stuck our replacement sounder to the inside of the hull with a big blob of blu-tack. Is has about half the range compared to the intermittently working through-hull sounder (~50m instead of 100m) but worked fine like that. Wouldn't worry too much about it.

 

[Refueler]

The Sika is good to go but sounder face can come away ...

Personally I like the tube fitting and I would wait till there's plenty of time to do a good job of it. Till then Sika will be fine.

I've posted this before - but here goes again ............ its a tried and tested method that I and others have used for years ...

1. Remove tube and tranducer leaving the bumps and ridges of previous resin / fixing.
2. With scraper / putty knife remove the old resin as best you can. If really needed - a grinder can be used but with extreme care.
3. Once surface is reasonably flat, a few small bumps here and there are actually not a problem..... you spray area with Oven Cleaner.
4. Let the Oven Cleaner do its job and froth up .... it will lift EVERYTHING including dried leaked Castor Oil.
5. After a time - wipe away the Oven Cleaner and check to see if a second application needed.
6. Ok now you have a surface that has had Oven Cleaner ... you need clean fresh water wash away the residue of the cleaner.
7. Dry the area and you now have the cleanest resin ready surface you could ever get ....
8. Clean up the old tube similarly so its spotless.
9. Place tube to hull and turn till its upright best ... make a marker pen mark on hull and tube.
10. Using Play Doh or Plasticine taking care to NOT let its oily state muck up your clean area - you make a ring as a dam to stop resin etc flowing away.
11. Mix resin and pour in enough to create a small rise in level and fill the bumps and nicks ...
12. Place tube into the resin aligning your marks. Use tape or something to hold the tube while resin sets enough to hold it.
13. Once tube is fixed - pour more resin into the Play Dog ring around outside to create a more permanent mount.

Once all set - remove Play Doh and you should have a solidly fixed tube ... which should not leak ...

Then fill enough to ensure transducer bub is well covered when in tube. I always turn transducer back and forth to ensure no air bubbles and oil is completely under and over. I also do not have transducer touching hull ... it is raised just slightly ... maybe less than a mm to avoid vibration from hull being passed into the bulb.... I adjust the nut accordingly.

I know there are many ways to do it and I am sure they all work ... the above is way I do it ..

 

[ANDY_W]

Before the days of sailing forums, when I was less knowledgeable, I had the problem of installing
a transducer from scratch. I knew that I had to avoid an air gap.
Having cut the foot of the tube to match the slope of the hull, I roughened up the fibreglass
and put a great big dollop of filler on the spot and stuck the bottom of the tube in it.
When the filler had set, I part filled it with grease and pushed the transducer into it
until the grease overflowed back up the tube thus ensuring no air gap.
The reasoning was that the grease would never get warm enough to flow so there was no possibility
of a leak even if the tube did have a gap.
That lasted until I sold the boat 15 years later.

 

[Daverw]

Ours been stuck down for last 4 years, never had a problem

 

[fredrussell]

Before the days of sailing forums...

Dark days, mention them not.

 

[John the kiwi]

9 years stuck into a blob of vaseline directly on the inside of the hull. Works perfectly and has never moved. apeears to work right out to the maximum range of the device. Why make it more complicated than it needs to be?

 

[QBhoy]

Seems like you have by mistake, come across the likely most often used means of installing a transducer. Very common method and even works with transducer designed for external mounting. I’ve done it for years like this.

 

[Spirit (of Glenans)]

Seems like you have by mistake, come across the likely most often used means of installing a transducer. Very common method and even works with transducer designed for external mounting. I’ve done it for years like this.

The 'castor oil on a tube' method was published in a 'tips and tricks' article in PBO around 2001-2. I used it for the fishfinder I installed in my first boat, a Leisure 17, which came with no electronics.

 

[Refueler]

The 'castor oil on a tube' method was published in a 'tips and tricks' article in PBO around 2001-2. I used it for the fishfinder I installed in my first boat, a Leisure 17, which came with no electronics.

It was the standard fixing method for most Echo Sounders from year dot ... and still remains a common recc'd method with many.

 

[ajames]

Thanks for the replies, I think I'll leave it in the sika for now and keep an eye on it over what's left of the season, if it shows any signs of trouble I'll likely go back to the tube and castor oil solution.

 

[Porthandbuoy]

Does anybody drill a hole and fit the transducer on the outside of the hull these days?

My transducer is shooting through about an inch of chopped strand mat and I suspect that’s why it won’t read beyond 35m.

 

[Refueler]

Does anybody drill a hole and fit the transducer on the outside of the hull these days?

My transducer is shooting through about an inch of chopped strand mat and I suspect that’s why it won’t read beyond 35m.

The usual reason is that an air bubble is trapped under the head. Even in tube + oil - it is common ...

It is also one of the reasons I do not let head touch the hull but raise it ever so slightly up ... by turning back and forth while inserting into tube - this allows air to escape round the sides .... till it just touches hull. I apply the nut till it just grounds on the tube cap. Then one turn more to just lift the transducer of the hull - a fag papers gap !!