A Stuart-based yacht brokerage is selling off a piece of cinematic history.    The 1979 60-foot Striker seen in the classic golf comedy “Caddyshack” is up for sale.    United Yacht Sales broker Joe Longobardi is the listing agent for the boat used in the 1980 movie.  The boat is probably best remembered in the regatta scene, when Rodney Dangerfield’s character, Al Czervik, , raises a ruckus on the water that ends with Czervik’s vessel, named “Seafood,” dropping anchor into a smaller boat owned by stodgy Judge Elihu Smails, played by Ted Knight.    Placed on the market about three weeks ago with an asking price of $349,900, the boat is based in Stevensville, Maryland, but Longobardi acquired the listing through his connection to the owner.   The interior of the boat even includes a life-sized cardboard cutout of Dangerfield’s character.