Hi
The distance wont be a problem. You are suppose to be on the boat and the boat is no more then 7-8 meters long.
The boat will have a Garmin Multi Function Display. And the owner of the boat will have a Garmin Marq Captain watch. And through the watch we want the ability of getting boat info and steering the boat, controlling the onboard music interface etc.
But my understanding is that MFD is limited in speaking CAN-BUS. So we will need to have a Linux Gateway for some more detailed implementation in order to steer the boat. And there we will implement own protocols to get commands from a connected Garmin device/watch.
We want to get info of the Boat, speed, position etc. and this should be possible to get from the Garmin sensors, I think.
But than we want to be able to start and stop the boat, steer it, have an owner and a list of connected users. A lot of this will need even to be implemented as a mobile app, to get a good user experience in my belief. But even if we would do it in the watch itself it should require own ANT protocol implementation and would require some time. And this is what I am trying to determine.
As you say it is probably not a problem to create own protocols. But It is more time demanding than if we had what we desired through ConnectIQ API or through Garmin Apps. Which was the belief when the project had started, that there are a lot of Garmin apps or built-in functionalities that we could use without to much effort.
best