[PC][2000s]Pirate game involving moving across squares to eventually find the treasure

Platform: PC

Genre: Pirate, 2d, similar sort of layout as minesweeper visually but different gameplay

Age: Probably early 2000s, but not entirely sure

Graphics: Similar look to minesweeper but the tiles are blue, which you move the ship across these tiles to reveal what is underneath

Noteable characters: You control a ship with a white sail, there’s ships with black sails and torn sails, as well as a living seaweed monster thing (all enemies).

Noteable gameplay mechanics: You move your ship left, right, up and down to reveal what is underneath the tiles, which is often enemy’s which you fight. Ideally you find the treasure map which flashes a tile green where the treasure may be. You win when you get the treasure.

Any help would be appreciated, cheers