The Kantronics device is interface with a computer to send digital communications over the radio, kind of like email. It utilizes several different modes and will likely receive wefax as well. You can look at kantronics.com or search on amateur radio sites like eham.com for more information. I'm not very adept at digital modes, other than morse code, so I can't offer much more than generalities.
The Icom M700 Pro is still being produced By Icom. You can look at icomamerica.com and search the products for marine SSB. I am more familiar with Yaesu radios since that is what I have, but if the Icom is working I would keep it; though you may want to have it aligned. They have a good reputation and produce quality radios.
The AT-130 is a device which matches the impedance of the radio to the antenna so you don't burn up the transistor amplifiers RF amplifiers. You can download the manuals for both of these from their website. Again ham radio sites such as eham.com could be a big help with more information. Look at their product reviews pages.
Another possible route is to get in touch with local amateur radio operators. You could start with eham.com or try arrl.org. I don't know where you are located in the world but even though the ARRL is in the USA they can still help you get in touch with hams world wide. Ham operators may not use marine SSB frequencies but the equipment is essentially the same. Also, a license probably required to use this legally and safely.
Hope this helps, Michael