Well-spotted!
"...the craft pictured at right was the first amphibious vehicle in Alaska. The "Honukai" (Sea Turtle) was designed by Dr. Thomas A. Jaggar, founder of the Hawaiian Volcano Observatory and a world-acclaimed geophysicist, author and inventor. He built his steel-bodied "beach boat" on an elongated 1926 Ford chassis mounted on oak timbers with a Smith Formatruck rear axle attached. On land, the Honukai could travel 25 mph. Twin screw propellers drove it in the water, while the front disc wheels served as rudders. The radiator set on top of the cabin, while a cooling pipe for the circulating water encircled the boat below the water line. The Honukai was used successfully on a 1928 National Geographic expedition from Shumigan Island to King Cove. Its exceptionally low gears allowed the crew to drive right up the sides of volcanoes. Jagger later provided his vehicle data to the War and Navy Departments. A November 1945 article in Popular Mechanics describes how the famous Army duck (DUKW) and Weasel amphibious truck were descended from Jaggar's Honukai"