Nice find!

The naval combat mission is way too easy by default. I lost a ship on the first try, and hasn't lost another ship thereafter.

Putting the difficulty at -2 gave me a really tough fight. I think the two groups of enemy ships sticked together better and formed one big firing line. They intersected my line and took bowside raking hits. In return, they gave my rear ship some stern side raking hits. I lost my 4th rate rear guard in the first run but did manage to wrestle the wind from them. With wind on my side I was able to switch around ship orders to spread out the damage. Then manually controlled the individual ships's firing arcs to focus auto-fire on one enemy at a time and sank them all. In the end, my Namur's hull was in the red on one side. Prince was lightly damaged. The other three ships afloat have hull in the red on both sides. If the French fleet had just one more ship I probably would've lost the majority of the ships. This difficulty setting makes it much more interesting, although I wish for a way to add more ships into the mission.