A submarine.
Swim down and knock on the hatch. (In Sweden we have a running tradition of telling jokes about stupid norwegians. They do the same about swedes)
I stalk. " "Really I go swimming and for long hikes" "I know.".
Submarines.
He's the one with a parachute on his back.
Four, one to change it and three to comment on the changing.
So the Marine have something to hold on to.