Hall PH "Hall boat"
An unassuming flying boat, with the distinction of being the largest Coast Guard aircraft when entering service, and being the last biplane in US military service.
Hall Aluminum Aircraft produced very few aircraft themselves, but the Hall's were responsible for the invention of cheap aluminium manufacturing in 1886 and so were fundamental in working with the US Navy to develop aluminium aircraft.
Given a contract for a production version of the Naval Aircraft Factory PN-11 - itself a development of the Felixstowe boats of WWI - 9 PH-1's were built for the US Navy. A second contract for the US Coast guard led to 7 unarmed PH-2's, with a second batch of closed cockpit PH-3's.
With the coming of WWII and a more active role required for the "Hall boats", the PH-3's were rearmed (including carriage of 4 depth charges under the inner wings - hidden by the floats in this view), and after Pearl Harbour adopted a naval-style marine colour scheme.
The PH-3's were finally retired in 1944.
Oops, forgot to add the "shipbucket.com" text