I am not aware of any water intrusion issues with those units. If the unit locked up I would doubt it is water related. Units that lock up are usually problems with power or software. When there is water damage with a unit they usually don't turn on anymore.

First try a software update and then ensure that the unit is getting enough voltage. Keep in mind that will change throughout the day as your battery drains so if this occurred near the end of the day that may be the issue.

If you have an issue with the unit contact Humminbird and they can let you know your service options.

-Lawren