Fleet experience with the VE-7/9 aircraft suggested potential improvements in catapult-type seaplanes.  The UO-1 was basically the VE-7/9 design with a new engine; (initially the Aeromarine U-8-D engine, followed by an early change to the Wright J-1 radial air-cooled engine.)  Basic structure of the two-bay biplane was largely unchanged, many parts were interchangeable.  Along with the radial engine, the other most obvious changes were the rounded fuselage sides, faired out behind side-mounted fuel tanks alongside the forward cockpit, and a new vertical tail.  Other than the Wright J-1 radial engine, and a redesigned center section and tail surfaces, the UO’s were outwardly identical to the VE-9’s.  Fitted with floats, the UO’s replaced the VE’s on ships because of their higher stressed pontoon and wing fittings.  In 1922, the Navy placed an order for 141 UO-1’s the fledging company’s first big military sale.