ITC-5 depth issue

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Dean,

Q1. In 2010, right before departing Rhode Island for Florida, the ST60 TriData developed an odd problem where the SeaTalk portion of the device caused problems for all the other devices on the network. After debugging it with a local marine electronics guy, we "solved" the problem by cutting the SeaTalk wire in the connector from the ST60 TriData (effectively isolating it from everything else), which allowed the other devices to work correctly, though without depth information. The ST60 TriData device continued to provide depth info just fine, so we proceeded to Florida without incident.
A1. Based upon the symptom and action taken by the technician, it would appear that the ST60 Tridata experienced a failure of its SeaTalk communications circuitry. Should a product having a failed SeaTalk communications interface be networked via SeaTalk communications protocol of other products having a SeaTalk communications interface, then communications between products within the network will be interrupted. Disconnecting the product(s) having a failed SeaTalk communications interface from the network will restore communications within the SeaTalk network. Similarly, severing the SeaTalk Data lead (yellow) within the SeaTalk cable which is connected to the product having a failed SeaTalk communications interface will permit the failed product to be powered by the SeaTalk network, but prohibit it from interfering with the communications between other products within the SeaTalk network. In the case of the latter, care must be taken to ensure that only one SeaTalk cable has been connected to the product having a failed SeaTalk communications interface.

Q2. Two years ago, I decided to begin updating the electronics. We added the iTC-5 to use the existing transducers; an i70 display in place of the ST60 TriData; a SeaTalk 1 to SeaTalk ng converter to supply the transducer info to ST4000 autopilot, the ST60 Wind and ST60 Graphic Repeater; and an A65 MFD centerpiece to the whole thing. It has all worked great, except for one thing - the depth being reported periodically surges from the correct value up to about twice the value, then wanders back down. Literally, I'll watch the i70 show the correct value of 6.2ft (for example) then over a period of a few seconds, the depth will climb to 13ft, hover there for a second or two, then just as quickly come back down to 6.2ft. I'm stationary, in my slip, just watching it. The boat isn't moving at all. Watching the depth on the A65 MFD, I see the exact same behavior. To prove that it isn't the transducer, I put the old ST60 TriData back in and put the leads from the depth transducer back in and the depth is correct, rock solid, no real variation. This system has exhibited this behavior for the last year-and-a-half, whether underway or docked, in deep water or shallow, going fast (okay, not really fast - it is a sailboat), or at idle speed - I even recorded a video of this weirdness. I've tried to see if there is a calibration, but I can't find anything that might adjust that. I'm out of ideas.

Here is another data point - about two weeks ago, I replaced the wind transducer at the top of the mast. It was an old mast head unit with the cylindrical pod with the new egg-shaped mast head unit. I connected the instrument leads directly to the ST60 Wind and recalibrated - everything was fine. Today, I connected the wind transducer leads to the iTC-5 and wind data started appearing on the i70, the A65 MFD and the ST60 Wind (through SeaTalk), so I was happy. As I stood there and watched, however, I watched the wind speed suddenly begin to increase, as if a significant gust just blew up, then subside, as if the gust passed. Now, granted, the transducer is 50 ft up from where I was standing, but I didn't see any evidence of a gust. As I watched, this continued to happen several time. To me, it sure looked like the same surging behavior, but with the wind speed instead. What is going on?
A2. Did the i70 w/iTC-5 replace the ST60 Tridata? If so, and you have interfaced the depth and speed/temp transducers to the iTC-5, did you then use the i70's Transducers Setup feature to select the iTC-5 for Depth and Speed. With regard to the Wind issue, did you also use the i70's Transducers Setup feature to select the iTC-5 for Wind and then calibrate the wind transducer via the i70?