Roger Martin shared a trimmed version of this Hawaii Kai image with me via Facebook. I later discovered the image below on Pinterest. Given the pink color scheme, the name of “Hawaii Kai” (an area on O’ahu developed by Henry Kaiser) and the fact that a matching jeep was pulling the hydroplane, convinced me that Henry Kaiser owned this pair.

However, thanks to information supplied by the hydroplane museum (a place Ann and I visited the museum in 2015), I learned it was actually his son Edgar that owned the combo (Henry had his own fleet of hydroplanes). The Hawaii Kai hydroplane was built for Edgar in 1956. The wagon, by all appearances a slightly modified Jeep Field Ambulance, was being sold at that time as well.

Below is the image I found on Pinterest. Based on the text font, this looks like the image and caption could have been published in a jeep news magazine or a brochure, but I don’t remember seeing any color versions of those documents.

For comparison, here’s the Jeep Field Ambulance (images are from brochure form W-992-5). Note how the Hawaii Kai wagon has a sloped rear bottom (slopes down toward the wheels), versus the stock flat bottom as seen below from a 1955 brochure. It also looks like the Jeep Field Ambulance has different sized windows on the driver’s and passenger side of the cargo area.