This happened to me last Saturday.

I launched my boat about 8 or so. There was no need to launch earlier as the tide/current wasn't about to cooperate at an early hour anyway. I launched inside the boat marina at the Port Townsend marina and I slowly motored out passed the Coast Guard cutter around the corner. The crew was active on deck, likely getting ready for inspection or perhaps preparing to deploy. At any rate, one of the crew was fussing about with the 50 caliber deck gun (complete with banana clip). He was unaware that I was motoring along directly in his line of fire as he swung the gun to the starboard toward the breakwater. As he looked down the sights he saw me with my arms fully extended over my head and grinning. I could see his momentary shock. His startled apology alerted the others who had their backs turned. They turned and seeing my grin started chuckling along with the gunman.

I said my usual, "Thanks!", but they couldn't make out what I said or what I meant (I'm not sure which) so I shouted to them, "Thanks for being there, guys!" and of course, in near unison, their response was, "Your welcome, sir!"

works every time