Sea Unit Service Medal Achievement
Sea Unit Service Medal20
Sea Unit Service Medal
At least 25 minutes unit usage plus used this unit type the most in the mission
[Single Player or Multiplayer] This is easy to do in the first mission while you have the PT boat. Simply move slightly forward and then wait 25 minutes with your engine at Stop. Then complete the mission and you will get the achievement. Otherwise, you can get it in the US Campaign. You can also boost for it online with another player.