A chief petty officer caught an AWOL sailor trying to sneak aboard ship. "Sailor, sweep every link on this anchor chain before morning or it's the brig for you!" The sailor found a broom, started to sweep, but a tern landed on the broom handle. He picked it off and tossed it overboard, but the bird returned and lit again on the broom. Again he tossed it, and again it returned, all through the night. The next morning, the petty officer inspected the chain and found it still dirty. "Sailor, what exactly did you do all night?" he yelled. The sailor responded, "Honest, chief, I tossed a tern all night and couldn't sweep a link!"

Good one Damien, love it. 
Robert