I have seen some threads here asking about that obscure childhood game, so I though I might give it a go. I have been searching for this game for a long time.
PC Game, strategy, used to play it all the time with my sister so could be played as multiplayer. The game was basically a big map with lots of squares, mainly water, two fleets of sailing old navy kind of boats and the idea of the game was to shoot down the enemy. You could attempt to highjack a boat if it was on an adjacent square to you and the success of the attempt I think was based on the health of both boats, there was different kinds of boats all with different firing ranges and mobility.
That’s all I remember of the game, pretty basic but offered me and my sister countless hours of fun.