Merchant Ship Play and Revenue

[Sir Garnet]

Facing Britain, the revenue-generating and supply shipping merchants seems to waste away. What should be done about the trade boxes? Are merchants buildable? Should they be built? How is it supposed to work?

Thanks.

[Captain_Orso]

The more enemy combat ships are in the shipping box(es) with your merchantmen, the less each of those boxes will return.

[Sir Garnet]

Can the player do anything abount merchant ships (I don't see an option to build them) other than try to keep the enemy out of the MTBs (or send privateers)?