During the First World War, there was a US Navy Cargo Ship named the USS Zirkel. I haven't been able to find out who the ship was named for, but I suspect it may have been named for Ferdinand Zirkel, the prominent German Geologist.
He was quite an authority on Geology during the late 1800's and early 1900's, and participated in the Geologic Exploration of the Rocky Mountains in Colorado, where Mount Zirkel is named for him as well as Mt. Zirkel Wildernes Area.
Can anyone answer my question?