Optional objective: Limit the ship's damage - 50%.
In this mission you will have to protect the merchant ship from the attacks of the gunboats. Try to stay as close to the ship as possible and shoot whenever you see an enemy. You can use both the cannons and the swivel guns. Alternate between using them so that you don't waste time on reloading.
The enemies will firstly come in from the left, then from the right and afterwards they will keep showing up from the left. Try hitting them from as far as possible.
Optional objective: Use a mine to eliminate gunboats.
Protect the merchant ship and eventually you will come across sea mines. Shoot them to make yourself a path between the rocks. The explosion of one mine is enough for a whole line to blow up.
Right behind the first line of mines, look closely to the left. You should note a ship beside a mine. Shoot it to complete the optional objective.
Optional objective: Limit damage from the fort's mortars - 50%
After getting out of the mined archipelago, swim towards the fort marked with a green point. You will have to destroy the English fortifications.
Swim with half sails and quickly turn around whenever you see a bell marking a mortar shot. Between the turns, you should fire a big salvo at the fort and hit one of the three towers. Keep repeating this until all the fortification are destroyed.