Here is agreat link to Ferry Services
from around the world, it gives web sites, e-mails, and info for almost every corner of the globe.
Personally I enjoy taking Boat s, the ocean is a pretty amazing thing and to watch the coast line disappear is quite a sight. I have taken the Ferry:
Ireland to England
England to France
France to England
Belgium to Scotland
Went Vancouver to Nanaimo ( Britsh Columbia)
Anyway, this is a grat resorse to use if you think you may need to plan something.