First year for the long running 18 foot series of trailers made in California & Ohio. Made in California first in October 1952 in a 17 foot version and sold as the Clipper, later under many names, most without a model nameplate, all the way to 1961. The early Ohio trailers in the O-2NNN serial number range were 17 footers made in late 1953 and early 1954, and I classify them as 1953's along with the California 17 foot Clippers.

 

Only the California trailers had the "whale-tail" end cap.