Comment 6 for bug 1191296

I replicate what I wrote in the forum:

Having one ship is not enough though, this will be very hard to balance. Imagine the ship contains 20 soldiers -> it will be nearly impossible to defeat it so it is very, very strong. If it only has like 8 soldiers or so it will not be able to conquer a castle though.

In my mind, the correct approach is a military expedition with more than one ship (but no new ship type). Each ship packs 6-10 soldiers (I think 8 is a good starting point for testing this out). Sea warfare is then super expensive (because you need a lot of ships) and can be scouted (i.e. when your enemy sails his ship close to you shipbuilder he will see you are building an armada which gives time to prepare and fortify). The armada will only be able to land at a port and in its immediate vicinity and all ships will become 'military buildings' of their own right.

This will not happen before b19 - and there are lots of bugs in the current seafaring that needs fixing before that.