The Mystery Plane
Patrol plane being brought up on deck of the USS Cumberland Sound AV-17 for servicing, 1944
The four-engine seaplane pictured on the Air Operations page appears to be a captured Japanese Kawanishi H8K2 (code name – “Emily”). Another photograph and mention of this plane can be found at the PBY Memorial Foundation web site.
From the National Archives by way of the PBY Memorial Foundation - Could this be the same plane seen being hoisted aboard the USS Cumberland Sound?
The following two photos are from Wikipedia.
A Japanese Kawanishi H8K (Allied code name "Emily") in flight in July 1944. Seconds later it was shot down by a U.S. Navy Consolidated PB4Y-1 Liberator of Bombing Squadron 115 (VB-115) from which the photo was taken. Source: U.S. Navy National Museum of Naval Aviation photo No. 1996.488.161.026 and 2002.019.007
A captured Japanese Kawanishi H8K Emily taking off at the U.S. Navy Naval Air Test Center at Patuxent River, Maryland (USA), in 1946-47. Source: U.S. Navy Naval Aviation News August 1947
A photo of this plane can be seen here. It is now on display in Japan at the Kanoya Naval Air Base Museum.