It's a little known fact that the US Army had a seagoing arm: tugs, coastal minelayers (called "planters") and service vessels.
I snapped this shot as best I could in the Ft. Mott, NJ visitors center. It's a small craft used to set and service the electrical distribution boxes for coastal mines.
My grandfather ran one in the Delaware River and Bay. I have his master's license. I am not sure but I believe if you captained an army boat you were a Sgt.
Other than the photo of three L-Boats acting like PT-109 and crew, I'm still researching their history.
Anyone with tips? Be glad to follow them up. I have found this photo; one other photo on the web; and a set of basic specification drawings. Narratives seem to be scarce and I don't know if any were used overseas in WW2.
Photo: US Army Distribution Box Boat, 1941
The Army also had tugs, barges, motor "yawls." I believe the book "Tug of War" by Joe Richards describes his adventures on a seagoing Army tug. He's the author of the fabulous sailing book "Princess: New York."