Wouldn't fit this game at all, imo.

Portals exist so that you can get from place A to place B quickly (except with metals of course).

Boats are supposed to be a big part of the game, no doubt, since it's a viking game, but they're not supposed to be lived in or on. Nor would that make any sense in a setting like this. They can also transport what you can't teleport, as can carts.