I70 depth readings not true

[langley.gace@gmail.com]

Hi Chuck,

Took the boat out for a test as prescribed above today. I disconnected the ground on the ITC-5. For our 95% of the 40 minute test the depth read true readings. There was about a minute at 70 feet where it had strange readings (0, or close to it on the I70 MFD and 6554 ft on the Ray Marine chart plotter. These erroneous readings on the depth were similar in nature to the readings I had with depth when the ground was attached. Other than that odd minute or two the depth behaved.

The temp behaved the whole time but the speed and thus the true wind speed did not. The speed stayed at 7 kts +-0.2 kts the whole time. I had my SOG on and it behaved giving me the readings I should expect. At the dock my SOG read 0 and my speed through the water read 7 kts.

As expected my true wind on the I70 MFD gave erroneous results while my apparent wind on the I70 MFD and the ground wind on the chart plotter gave what I believe to be good results.

Next steps?

Many thanks in advance,

Langley