Use it on your boat and then transfer it to your car. In the matter of fact, you'll have it both in a very single device.

When utilizing Garmin for Marine, it is best to first check the location when you are on the shore and market that down in your unit, in the event you get lost while you are out on the water.
You can get to your destination in a quicker, safer, simpler manner by knowing where you are and where you need to go. Particularly if you are in water that you are not familiar with or a quick storm makes visibility nearly impossible. Perhaps to make use to mark your favorite trolling point.