ST30 Bidata Depth Sounder Issue (2004 model)

[sir jasper]

The instrument will not measure depths less than 4m or greater than 40m.

At these depths, the display shows the last good measurement with a flashing “m” to indicate loss of signal. While I’m not too fussed with the loss of measurement at 40m, 4m is a different matter.

Any ideas as to the cause?

 

[AdeOlly]

Interesting coincidence, I was going to make a similar post. I have a similar issue with my ST30 bidata. As with yours, it loses the signal, but it can be 5 or 6m deep when it does this. However, this mainly only happens in Chichester harbour. It seems to work fine elsewhere in shallow areas and on berth where it will happily register the depth (~2-4m) with no problem. I was wondering if it was the fact that there is quite deep mud in much of the harbour which was causing a poor signal return. I've seen greater than 40m on mine recently going past Hurst, but it's not often I'm in water that deep.

 

[sir jasper]

It appears to be precisely the same issue/fault. I’ve also made the correlation between loss of shallow depth measurement & a muddy bottom. The boat is new to me so I’m unsure if the transducer has always had issue getting a clear return signal from mud – what is your experience?

My previous boat had ST60 instruments & never had any issues in the same locations.

 

[AdeOlly]

All I can really add to my earlier post is that my transducer is mounted inside the hull so has to shoot through the thickness of the GRP hull, and of course receive too, which will invariably cause some loss of signal strength.

With reference to Chi, sometimes it only gets a reading every 20-30 seconds, esp north of Mill Rythe, but it's fine nearer the entrance which is subject to stronger tidal flow. If memory serves it was a little sporadic on the Beaulieu river a few weeks back too, but it shows no problem on the Medina, or going close to the shoreline anywhere. It was also fine the last time I was in Poole harbour which is muddy, and I watch the sounder like a hawk when I'm there. Must be something about the Chi mud

 

[sir jasper]

Without knowing if this is a performance issue with the ST30 instrument, its difficult to know what to do next. Before I consider replacing the transducer I’ll try contacting a few Raymarine dealers.

If I get a definitive answer I’ll drop you a line.

 

[Gumpy]

Without knowing if this is a performance issue with the ST30 instrument, its difficult to know what to do next. Before I consider replacing the transducer I’ll try contacting a few Raymarine dealers.
.

Mine has given up entirely, looked for a transducer but they are silly money .
If you find a supplier at a reasonable price let me know.