Thanks for these replies. Helpful. Still confusing though. I have seen guidance along the lines of..."must be within 30 feet of tracker at all times". But then I see things like it's ok to land ashore in certain locations, and "30 foot rule does not apply to dinghy." What does that mean? Do you need to take the box with you in the dinghy? Carry it with you while on shore? Would I be able to take crew in dinghy, say 100 yards from boat to snorkel along shoreline (without contacting others, etc...). Confusing. Anyway, thanks for replies.