The Duffy 26 hull is molded in solid Fiberglass Reinforced Plastic witha vinylester skin layer and full length longitudinal foam cored stringers; the hull is white gelcoat. The solid fiberglass skeg and full keel protect the propeller. PVC spray rails are through-bolted and glassed on the interior.

The interior deck and seating are a single mold in FRP with foam coring. All deck, step, and seating areas are molded; the surfaces are white gelcoat and the non-skid painted a light gray.

Engine mounting brackets are throughbolted to the stringers. The engine, transmission, shaft coupling, battery/battery box, and high water alarm are installed under a FRP, sound-proofed engine cover vented with a closable fitting. The fixed fire system is also located in this space. The cover tilts forward for maintenance and inspection access. A fiberglass drip pan is installed under the engine. The wet exhaust and muffler exit through the stern.