Listed in "Who was Who in American Art" as the "Baltimore port painter" Otto Muhlenfeld is known as one of the premier regional marine artists of the greater Chesapeake Bay area. Specializing in ship portraiture, many are of the harbor and waterway workhorses, the steam tugboat. While not considered as glamourous or fast as the yachts and large merchant ships, tugs proved to be amongst the most stable ships in service, in all varieties of weather.
At one time, in 1898, Otto was identified on the Baltimore City rolls as "Muhlenfeld brothers, ship painters", in conjunction with his brother John. A mix of portraits directly commissioned by owners and captains have surfaced with a relative few other known works with subjects chosen by the artist completing his catalog. His paintings are comparable in the draftsman-like precision of the works of the Mississippi region's bard brothers and New York's Antonio Jacobsen.
It is believed that the brothers are first-generation Americans born to German immigrants living in Baltimore. All the paintings are marine related to ships and the greater Baltimore harbor area, either showing area headlands or portraits at sea.