ST4000 tacking functionality

[hynnimac]

I have the remote (100) so that I can single hand my Catalina 36. It allows me to be away from the helm to trim the sheets while at the same time using the 100 to tack the boat. I turn on the nav instruments (bringing on the auto pilot ST4000 and the a75 with the auto pilot “on” in settings). then the remote 100 is turned on and moved to wind setting and then to Tack setting. Using the remote I attempt to tack. sometimes int works and sometimes not. I’ve attributed the failures to insufficient boat speed. I’m never sure whether I should be in auto pilot in the ST4000 before changing the settings in the 100 (Wind + tack). On occasion the word “Error” has been displayed on the a75 MFD when the tack does not complete itself.

I’m just not sure how these 3 devices are supposed to interact with each other and whether I’m doing something wrong. The manuals are silent in this area of concern.