Press Photos by Tim Gilman Captain Bob Keifer, seated at the ship's steering wheel, and first-mate Donna, wife on far right - seated too, hold a backyard boat send-off party for family and friends before towing their 22-foot pontoon motor boat to a dock site on the Hudson River where they spend much of their warm-weather weekends and holidays. Enjoying music, food and beverages with the Keifers, who reside in Bethlehem along East Washington Avenue, are their son Bob and wife Tammy and Scott McEllroy and