Skiffs up to 16′ for outboard, oars propulsion, or sail. see the dinghies category too.. Osprey 18 flats skiff. the osprey 18 flats skiff was originally designed for a client (who stiffed me on half his bill!) in louisiana back in 2008.. Boat plans catalog – 300 boats you can build! boatbuilding supplies & epoxy; inboard hardware; new – electrical design plans; books, dvd’s & audio.