Another of the old days of Market Hunting gunboats
Both types were outlawed in 1910 if memory serves right.
As was sink boxes. Migratory bird treaty 1918. They get around the sink boxes now using cold water survival suits and wading out in the flats.
The Havre Grace decoy museum is a must see if any one ever hunts or visits the Chesapeake. Lots of history in that museum.
The OP's picture is actually are two Feds.
Canvas backs use to bring a lot of money. Outlawgunning was a huge black market for decades after the treaty