Alternative for not working Sonic Speed sensors

Willem Kroes


I am quite new to this group, but owned from 2002 to 2010 a Santorin sloop (#69). Now I am on my way buying a SM 2K from 2001. Also on this SM (I have seen already quite a few with the same problem) the Sonic Speed sensors are not functioning.

Which options do I have? 

1. Buying a new sensor with paddle wheel that works with the Hydra 2000 system? Which brand and model do I need?

2. Buying a new sensor without moving parts. Which brand and model working with the Hydra 2000 system is recommended?

Willem J. Kroes

Alan Leslie

Hi Willem,

I have the same issue.
I'm going to buy an Airmar Model: CS4500-610 Ultrasonic Sensor and put it in the depth sounder hole and then buy an Airmar P79 in-hull depth sensor for the depth...that way no extra holes in the boat and hopefully a reliable system.
This not my original came from Bill Kinney..

Elyse SM437

Peter Jaeger

I also had to replace my sonic speed from B&G. Stéphane from Pochon recomended this:
To replace the Sonic speed system we install the Ultra Sonic sensor by NKE (in housing),since 2 years on each Amel 55 we used this sensor and it works very fine.
This sensor is quite expensive therefore I followed Bill's recomendation and installed the Tinley NMEA paddlewheel. I have now SOG from the GPS on my Hydra network. Quite easy to install.
Wilson / SM 003 / La Rochelle