Echo sounder and anti-fouling

[Alan S]

I am about to fit a Nasa Target 2 echo sounder with the transducer bonded inside the grp hull. Extract from instruction leaflet...

"It is important that the face of the transducer is thouroughly bonded down to the hull. A single air bubble will cause a considerable loss in performance.
The transducer and place of mounting must be kept entirely free of any antifouling compound as this can also affect the performance of the unit"

(my bold)

Would a couple of coats of a/f really be worse than a colony of barnacles?

 

[Roberto]

Don t know about the Nasa one, but my Raymarine transducer must have an accumulated zillion of antifouling coats and there is no appreciable drop in performance.

 

[Seashoreman]

I am about to fit a Nasa Target 2 echo sounder with the transducer bonded inside the grp hull. Extract from instruction leaflet...

"It is important that the face of the transducer is thouroughly bonded down to the hull. A single air bubble will cause a considerable loss in performance.
The transducer and place of mounting must be kept entirely free of any antifouling compound as this can also affect the performance of the unit"

(my bold)

Would a couple of coats of a/f really be worse than a colony of barnacles?

Maybe they are referring to the good old days when antifouling had more ingredients than emulsion paint. I installed a transducer in an internal tube 20 years ago and it worked perfectly fine with lashings of antifouling.

 

[Alan S]

Thanks for replies. I suspected that would be the case.
Just had a thought though - perhaps antifouling would be unnecessary as the ultrasound would prevent fouling?

 

[Seashoreman]

Thanks for replies. I suspected that would be the case.
Just had a thought though - perhaps antifouling would be unnecessary as the ultrasound would prevent fouling?

Transducer is not active all the time and I imagine most fouling is picked up when stationary. Its an interesting idea
but certainly one I have never encountered. Just slap it on.

 

[Fantasie 19]

I am about to fit a Nasa Target 2 echo sounder with the transducer bonded inside the grp hull. Extract from instruction leaflet...

"It is important that the face of the transducer is thouroughly bonded down to the hull. A single air bubble will cause a considerable loss in performance.
The transducer and place of mounting must be kept entirely free of any antifouling compound as this can also affect the performance of the unit"

(my bold)

Would a couple of coats of a/f really be worse than a colony of barnacles?

Confusing to say the least - they way I read that, it's saying don't put antifoul on the inside of the hull ('the place of mounting') ie. between the face of the transducer and the hull??? If it's just clumsily worded I agree with everyone else - I've anitfouled as normal for years with no detrimental effect, the transducer is also still sitting in it's original blob of butyl putty which I used as a test to make sure it worked ok in the position I'd chosen - it did so I never changed it...

 

[justanothersailboat]

I'm sure they're just covering their b... elow waterline hull... against complaints.

My depth transducer - and pretty much every inside-hull transducer I ever saw - sits against hull that's antifouled on the outside. Otherwise I'd have to measure the exact position somehow and leave a bare patch which would then get even worse than the hull itself.

Even quite severe fouling doesn't seem to affect them much. You just get deaf barnacles in that one spot.

 

[Refueler]

Thousands .. nay - millions of boats around the world have AF on outside of hull and Trsnducers quietly click away performing fine. You may lose a few metres once you get into real deep water ....

My Sunrider has Echopilot dual which is basically same as the Nasa dual .. the E/S transducer is in a tube with Castor Oil ... must be loads of antifoul on outside of hull as its never been scraped back in all the 25 odd yrs I've had the boat ... that E/S shows happily depth crossing Baltic until it hits over 100m - then it may show dashed lines occasionally ...

My Conq 38 with also inside hull transducer for the Garmin 92sv with Hard Racing A/F and the other tranducers that are through hull to the B&G network - all show similar action .. and will both go off at depths in the over 100m levels ...