CrewWatcher is made for non metal vessels up to 45 foot.
Wireless signals, especially high frequency signals like Bluetooth have trouble traveling trough metal substances. Hence, using Crew Watcher on large metal vessels is not recommended.
That said, the beacons are equipped with a specialized, long range Bluetooth 4 antenna.
This makes for up to 200m line of sight range. (no obstacles) This range is meant to cover only the boat.