Have you tried a GPS dog tracker? Would it work as a tracking device for a boat or tackle box should they get stolen.
For tracking a dog a GPS unit at $10/mo probably isn’t worth the money since the radio units can go for several miles and don’t require a monthly fee.
https://www.thepawtracker.com/blogs/the-pet-tracker-blog-by-the-paw-tracker/84621315-top-13-gps-pet-trackers-dog-and-cat-cell-phones-best-of-2016-reviewed