Okay, had to laugh

I am playing LA Ulm in a MP game and I have started on a island, completely surrounded by water.
Fortunataly, its a fairly big island, 20 or so provinces, so is a fairly safe and secure base. I think every LA nation is present in the game. So my main threats are LA R'lyeh and Atlantis. Also Marignon with its sailing and Midgard has sailing as well. Anyone else?
So how would you go about
:-
1) Getting to the mainland, securing yourself a base there.
2) Defending your island home.
Assume my pretender is of no help whatsoever and remember LA Ulm has no access to water magic.