You have a heavily modified TM don't you. Sounds like the surface marker the stock game uses to mark the position of your submerged sub. TM replaces the file that makes that with a zero byte file. That's how I know your TM isn't kosher. To prove that is what you're looking at there is a keyboard command to kill the marker. I'm at work now and can't check it out. The Japanese can't see that color so you're safe. Or at least as safe as you can be in Trigger Maru.
