NASA Clipper depth playing up

[graham]

Our 12 year old clipper depth seems to work up to about 5m but then displays constantly different readings.

I have an un used spare Nasa Target transducer .Does anyone know of it will work on the Clipper display unit?

If so I will give it a try ,,You never know your luck!

 

[Graham376]

Their site just lists one transducer under spares, worth connecting it and just trying it lowered overboard. Depth Transducer (with 7 metre cable) - Nasa Marine Instruments

 

[Minerva]

Is your transducer mounted external to the hull or in a tube inside the hull?

If internal then check you have enough fluid (olive oil) in the tube betwixt the hull and the transducer.

 

[graham]

Is your transducer mounted external to the hull or in a tube inside the hull?

If internal then check you have enough fluid (olive oil) in the tube betwixt the hull and the transducer.

The transducer is bonded to the inside of the hull in our boat doesnt seem to be unstuck, used to work quite well until recently.

 

[Graham376]

Just remembered, a while ago one of our instruments was playing up but can't remember which. It turned out to be a corroded aluminium coax plug where wire connected to display. Replacing the plug sorted it.

 

[graham]

Update on this. I installed the unused Target transducer on the existing Clipper echo sounder and all now works perfectly. I fitted it internally in an oilbath made from a bit of 1 1/2 " plastic drain pipe glassed in.

Checked the position by temporarilly sticking the transducer in place with blue tack to find a good spot.

Using vegetable oil from ASDA doubt it makes any difference what oil you use.

 

[Refueler]

Quite often its due to air getting under the head and interfering with 'sound pulse' transfer. I have seen many times transducers glued to hull and seem fixed ok. But when pressed - have come away and then a small crack seen in the glue ...
In tubes ... if air creates a bubble or similar in the oil - same can happen.

Veg oil is fine ...

It used to be recc'd to use Castor Oil ...

In fact you can even use water ...

 

[Refueler]

Another possible .... I was always told that the transducer - if mounted in 'tube' ... the transducer face should not touch the hull. Particularly if the hull has an angle to the horizontal. It should have a tiny gap .....

Whether true or not - that's what I was told and how I mount.

 

[Spirit (of Glenans)]

Is your transducer mounted external to the hull or in a tube inside the hull?

If internal then check you have enough fluid (olive oil) in the tube betwixt the hull and the transducer.

Castor oil is recommended for this application, as it does not go rancid, unlike other vegetable oils.
I've still got a half litre left over from my first boat, twenty years ago. It has no signs of rancidity.

 

[PaulRainbow]

Rather than using oil in the transducer tube, use anti-freeze.