I have been using Furuno NAVTEX for years. For the type of sail that you describe, it will work very well, very reliably, at an affordable price (<$300). The NAVTEX spec is 250-nm offshore, but 450-nm is very common reception.
A down loadable pdf of the product brochure is on the following URL:
NAVTEX RECEIVER NX-300 | Navtex | Communication | Marine Equipment | Products | -Furuno Electric Co., Ltd.