Thank you very much for your tip
Since i am in a bit of a hurry today i will have to write in English.
( sorry for the inconvenience )
I sent an E-mail to DSB in Eschershausen and they were able to find out that my boat is a Zephyr 504 from the mid 80's.
From the Boot nr... they also were able to see that the boat was sold to the Danish company Viking-lifesaving-equipment and they told me to contact them for further info...
Luckily that compagny has its main office in Esbjerg where i live so i went over there to ask a few questions.
At the main office they managed to dig up some older lists of DSB boats they had sold on to the offshore industry , and after a few minutes they found out that my boat had served
as a MOB - boat on a supply ship sailing in the north sea.
Also it became clear that the boat had been sold as a package with a 25-hp mariner engine. but they could not tell me the maximal engine size allowed on a Zephyr 504.
So now i hope someone in this fine forum have some experience with the 504 and maybe even know how much power its safe to stick on a boat like that.
Thank you all in advance
Steffen