(DG) ST 60 speed

[cdt]

HI Derek

Thank you for your reply.

There is no fouling under the boat and no obstruction near the paddlewheel.
We tested the paddlewheel and it contains 2 magnets, as does the ST800 P120 replacement that we purchased.
We took the new transducer for a test run and it read 3 knts when the GPS registered 5 knts, I can correct this with a calibration of 1.6, but the speed becomes very unstable.
As both the new and the old transducers read the same, could it be the display unit? If so, what unit should I use to replace it (ST50 or ST70)?

Thanks

Conrad