An upgraded O3U-4, the major change being the use of the latest P&W “Hornet” R-1690D engine and the incorporation of an enclosed cockpit.   

The seaplane version contains the same equipment and engine as the landplane.  Some of the 03U-6’s were delivered as float planes and others were converted to float planes by the Naval Aircraft Factory.  Records are unclear as to the final quantities.

An order for 32 O3U-6’s was placed soon after the SU4 order.  The XO3U-6, used for flight testing to convince the Navy to order more Corsairs, was included in this order.  These aircraft were flown by both Navy and Marine pilots since most were used to replace the older O3U or SU aircraft still in service.  Some of these aircraft served as late as 1941 when several were converted into target drones or radio controlled drones by the Naval Air Factory.  The latter were used for flight testing under hazardous conditions.  One O3U-6 used dual-position flaps and full-length ailerons across the entire wing.  It was designated XOSU-2.