No, you need to switch the region manually. Not a big deal to do for a couple of nodes.
The trickier part is to figure out the correct preset for more exotic locations. I've had to ask a couple of times from the local Meshtastic community group.
Many (if not most) Meshtastic devices don't have a GPS receiver of their own, and also may not be paired with a phone app to supply location. So at least some devices would need to sniff GPS coordinates from traffic on the wrong band in order to know it's time to switch to the new band appropriate for the new location. Some amount of automatic reconfiguration could probably be made to work, but there would be serious limitations on how many use cases it could handle.
I think the way to do it would be that you have GPS run a update script to sync the devices. Surely the boat has a GPS, right? Or there's a GPS somewhere in the system.
So to refine the gp's question: surely there's a way to push an update or sync with a script that can do this based on GPS coordinates, right?
I would think a syncing mechanism would be a big help anyways since regardless of the reliability of the GPS script you're still going to be doing this, right?
I agree, need central control and the boat the obvious choice as would need to send out to all nodes to switch and make sure all have received, so would want any switching done with a delay (say in 5 minutes switch to region XYZ), so the mesh does its magic to get the message out.
The trickier part is to figure out the correct preset for more exotic locations. I've had to ask a couple of times from the local Meshtastic community group.