Okay thanks. I have another question concerning merchants. The manual says merchants provide revenues when placed in a "sea zone under your control". Does it mean you can place them in any sea zone without enemy fleets? (exemple a spanish merchant off the southern coast of France) Or do they mean a sea zone adjacent to your national territory?
Actually sea zones are not "controlled" per se, so that sentence is kinda misleading as written. In fact you can move your merchant to any sea sone, but you should try to avoid those with enemy waships, for obvious reasons.