There are two different things you are considering.
A ham setup, Radio $350, tuner $150, wire antenna and feed line, $100. Doable, HOWEVER, you can not use that setup on the marine bands. Data, like email and fax might add a bit more.
A marine system is different in the fact that the radio is certified to operate within predefined specifications. With a HAM setup it is the responsibility of the licensed person to ensure the performance of the radio is up to standard.
It may be possible to use a Marine SSB radio with a modification on the amateur bands. The trick is in not negating the certification (to predefined specs) with the modification.
Two radios, one ham and one marine, could potentially share a tuner and antenna and work It won't be cheap, but it could be done.