Airmar P79 in hull transducer issues

[alexincornwall]

I've been having ongoing issues with our Airmar in hull transducer and hope that somebody might have some handy ideas.

This problem started towards the end of last season and we've just relaunched with a clean bottom and the problem remains (I naively wondered if fouling might have caused the issue). The transducer is mounted clear of the keel and definitely seated properly in a generous solution of antifreeze. I've also tried caster oil but no improvement. It's connected to our old ST50 display.

The transducer seems to frequently lose its ability to read the depth, notable because the last reading will flash before it pings the seabed again. I first noticed this last year, but only when the depth exceeded 35 metres or so; not really a worry. As time has gone by it's lost it's ability in much shallower depths, now down to a more critical 4 metres. It works most of the time, but often lets us down when we most need it.

I've heard conflicting suggestions that the transducer simply becomes less effective as the years go by. I've no idea how old ours is but my guess would be at least 10 years.

Is it time to plump for a new unit or am I missing something?

 

[Skipper_Christoph]

Are all the cable connections tight and not corroded?

 

[eddystone]

I've been having ongoing issues with our Airmar in hull transducer and hope that somebody might have some handy ideas.

This problem started towards the end of last season and we've just relaunched with a clean bottom and the problem remains (I naively wondered if fouling might have caused the issue). The transducer is mounted clear of the keel and definitely seated properly in a generous solution of antifreeze. I've also tried caster oil but no improvement. It's connected to our old ST50 display.

The transducer seems to frequently lose its ability to read the depth, notable because the last reading will flash before it pings the seabed again. I first noticed this last year, but only when the depth exceeded 35 metres or so; not really a worry. As time has gone by it's lost it's ability in much shallower depths, now down to a more critical 4 metres. It works most of the time, but often lets us down when we most need it.

I've heard conflicting suggestions that the transducer simply becomes less effective as the years go by. I've no idea how old ours is but my guess would be at least 10 years.

Is it time to plump for a new unit or am I missing something?

That’s encouraging I’ve got one of those on the chart table waiting to be installed! Still 10 years is probably OK for me as I’ll likely not be around then.

 

[alexincornwall]

Are all the cable connections tight and not corroded?

Pretty sure we're all good in that department, though will double check. It's the intermittence of the problem that's confusing...

 

[Poey50]

I changed our afters three years of very intermittent problems. It particularly seemed to dislike French waters so, suspecting it of Brexiteer sympathies, I swapped it out for a new one. So far, so good - although we're still in the transition period.

 

[tillergirl]

They fail! Sometimes and can be v. confusing until condemmed. The one that failed last year only happened when the water column was less than 2.5. Gave readings but they were inaccurate. Replaced - back ok.

 

[Boathook]

Interesting thread.
My transducer sometimes plays up and I find that by turning the sounder instrument on and off sorts it out in the past. If it gets worse a new sounder will be the order of the day.

 

[Yngmar]

Ours had the same slow death. Usually when bashed with a fist from the outside (it's through-hull mounted), it would work again for a while, until the next anchorage! We'll replace it at the next haulout and have meanwhile used the spare from inside the hull, which works fine through a wad of Blutack, no coolant needed