Ya gotta do like Elmer:
and as Red Devil suggests, do it deep when sneaking in, presenting the smallest profile possible. Even still, it's best to find a hole in the seam of the defense to "sneak" through, or wait for slightly rough weather, to help hide the "Shhhh!" of your electric motors, and the dingbat in the back that dropped the wrench!... "Fire One!" "Firing Tube One, sir!" "Third Class Seaman Dobbles in the water sir!"
