You're getting into deep waters!
The antenna coupler isn't _integrated_ with the FS1503EM -- it's a separate box, which needs to be mounted at the base of the antenna.
FWIW, the price at http://www.boatersland.com/fs1503em.html
is pretty good, considering the antenna coupler is included. But don't kid yourself -- installation is _not_ trivial.
The most common SSB on cruising boats now is the Icom IC-802, with a matching AT-140 (I think) antenna coupler. The older Icoms are also popular, and available used. Nothing good is cheap, though.
My opinion is that if you want to use -- and certainly, if you want to _install_ -- an SSB radio, you should study for a ham license.
That way, you'll understand a bit more about what you're doing.
Another possibility is to get an SSB _receiver_. That's considerably cheaper, and the installation just means running an antenna wire and 12v DC power. You'd get weather forecasts, and be able to listen to the marine nets. But you couldn't call for assistance.