I have used these for merchants. I would run a column along the diagonal of the table with SoG ships as escorts and interceptors. I assigned various levels of hit and sinking-victory points based on ship size. For an interceptor to hit, the appropriate ruler length had to touch the ships since they don't have bases. For each ship that successfully left the table at the far end, the escort team received victory points based on size of ship.

These can make for good obstacles in port scenarios, etc.