ultrasonic log

[rex_seadog]

The perfect answer to log paddle-wheel fouling (and hence removal), as referred to in recent threads here and on Scuttlebutt, would seem to be Echopilot's ultrasonic log. This has no moving parts but has a fixed through-hull unit that, I quote, 'correlates echoes from particles in water a few centimetres from the hull and computes to speed.' The big question is does it work? Does anyone have any experience of its accuracy and reliability?

 

[philip_stevens]

I think this is the same as Doppler logs as fitted to the container ships I recently served on. Those were very accurate.

regards,
Philip

 

[rogerm]

As Philip says they are doppler logs IMHO. Perhaps on container ships they can be kept far enough below the water line to work well. On our size boats they still manage to have problems. If fouled enough they still don't work properly and you have to be quite careful to place it well forward and low down. If that part of the hull comes near the water line or is in a position where some underwater feature that generates a bubble trail that goes past the sensor then the value read will be all over the place.
Roger