Thank you Steve (shipscribe.com) for helping us solve a piece of the puzzle. It appears that the ship in this picture is one of 2 “Sierra Class” ships built at the Vulcan shipyards in Stettin in 1912.
The “Heringsdorf” boat trip – aboard the HERTHA – (Series 6 1-25) began at Ahlbeck Pier and concluded with a journey through a busy port in Stettin.