The original size of the model sheets for “M. 142. Seetüchtige Motor-Kreuzeryacht mit Inneneinrichtung” (seagoing motor cruiser yacht with interior decoration) is 44.5 by 35.6 cm. No scale is given, but calculating back from the size of the door it should be 1:20. No instructions are provided, but then they are not really necessary.
The sheets carry the label “JBM”, framed in the lettering “Deutsches Erzeugnis” (made in Germany). Initially we assumed that the publisher was RAPI, but they usually did not include points in their article numbers (in this case, M. 142.). We could narrow the time frame for the publication from 1910 to 1920, which now lets us assume that the publisher could have been the “Verlag Julius Bagel” which was located in Mülheim (Ruhr). We know for certain that Julius Bagel published card models before WW I, but we are not certain whether they continued to do so after the war. All Julius Bagel models we know about have an article number beginning with “M.” so there is a strong indication that this model has been published by them as well. “JBM” would then stand for “Julius Bagel, Mülheim”.
The company was founded by Julius Bagel (1826-1900) in 1855 and was taken over in 1891 by his son Julius Bagel junior (1861-1929). It went into bankruptcy in 1924. There is still a printers’ company “A. Bagel GmbH & Co. KG” in Düsseldorf; however, it belongs to a different branch of the same family. Unfortunately we have no further information about Julius Bagel as a publisher or his company.
The model seems to have been constructed with a later addition of a screw and rudder in mind, which would presumably be made from a different material. This and the somewhat weird shape of the underwater part of the model let us assume that it was meant as an affordable alternative to the tin models which were very popular at the time, but also quite expensive. One sheet carries a note that the built model should be coated with spirit varnish. It seems certain that, assuming an appropriate finish, the model would swim, so we can safely assume that it was meant to be used as a toy floating on a lake, not just as a model to look at.
The 
“Modellwerft” magazine 12/2021 published an extensive building report with many photos of the building progress.
kartonmodellbau.org)