William A. Wetherell served as CMM on subchaser 206. This set includes photos from his service, included in a letter in the collection of Jim Felton (a collector of WWI-era postal history items).

An excerpt from CMM Wetherell's letter:

"…It is awfully nice to be a captain and everything. I was going to enlist as Admiral but, you know, there is no chance for advancement if you do that.

I enclose a snap taken at Philadelphia in a sailor suit. Since then I have been made Chief Machinist's Mate and have charge of the engine room of sub chaser 206.
The post card was taken on the "morning after" a speed run thru Jaxonville, however you can notice the difference in uniform. 

Sure wish I rated a private secretary. Address me ℅ Sub Chaser 206 Charleston, SC ..."

Thanks to Jim Felton for submitting the scans to The Subchaser Archives.

Photo Set - click to view large versions