Get a fist full of "I LOVE SAILBOATS" bumper stickers to paste on their transoms and on the rear bumpers of their vehicles. Who knows how long they'll go without noticing.

Or some San Francisco Rainbow Parade stickers

If you want to get him off the lake,find out his fax number at work.Go to your word pad and draft a letter saying his credit card would not go thru.The heading on the letter must be a drug company name,the order of 1 susbsciption of Viagra must be listed on the notice.Please contact us with a good credit card Mr. ******,Make it look good.

Put a fish in a three man water balloon slingshot and fire it across his bow, or if you wanna really get 'em, an octopus or squid.

if his boat is in a slip (mine is, so i check it all the time) you can get a big sign saying anything, ex; im gay, looking for gay parner, this boat sucks and so on, you tape this big sign to the very front of the hull on the side facing away from the slip (if he is backed in) it will work, and gets people going pretty good, and usually will make just about a full trip out.

Damn! Remind me to never piss off this crowd!

Toss a used condom in the cabin.

limburger cheese in the cabin

If he's got a boat manufacturer plate on his truck/car, take it off and put a Bayliner plate on there.