Like KevinC said, Uv5R isn’t any good for that. Assuming they are phase 1 conventional, you can get a used p25 radio on eBay for a few hundred, +software and cables. I wouldn’t recommend that unless you really know what your doing because programming them can be overwhelming for a first timer. That or get an actual scanner.
If you could provide some more information on that Coast Gaurd System you’re trying to monitor, we would be more than happy to guide you in the right direction towards a radio that will satisfy your needs.