This is a royal pain in the bottom. Hopefully, this guide will help. To prevent the ship getting damaged, you need to take a very specific route, and it's a bit tricky.
For the mine part, pick the second ship after the blockade.
For the fort, you'll need to master stop/starting the boat, because the fort will shoot where would you be, not where you are. good luck!
Optional Objectives:
Limit the ship's damage: 50%
Use a mine to eliminate gunboats
Limit damage from the fort's mortars: 50%
![](https://i.ytimg.com/vi/JY1kaEmDiWE/maxresdefault.jpg)