JOSE CARLOS FAJARDO/Staff photos
Friday the 13th was lucky for Brian Kerfs, 16, front, and his brother, Jeremy, 18, both of Pleasant Hill, top, who took first place at the fifth annual Derby Day boat race at Pleasant Hill Aquatic Park. Ten boats competed in the event, and all had to follow the simple requirements: that the boats be made only of cardboard, recyclable materials and duct tape. The Kerfs won using a refrigerator box. Dressed for the fun, Marco Ortega, 8, of Concord, left, does his best to waterproof his cardboard shark fin hat with lots of duct tape. For all their preparation, right photo, Ivanna Tran, 13, of Pittsburg, left, and Keri Monaghan, 13, of Pleasant Hill, suffer a watery end as their rubber duckie boat sinks during their race across the pool. But not all was lost as their boat won for the most creative design.