You don't "connect" a Garmin clock to anything - it is an independent device that registers whatever activity you choose to do. On some watches you actively start your activities, while others figure out by themselves that you are doing something and registers it for you.
There is a "surfing" activity that you can choose when doing the activity, but it will not capture any data from the surfboard if that's what you are trying to do.
At least that's how I understand it, and your question.
