My guess would be that it is the front part of a Dornier 24 (there was no info marker), what is missing is the upper wing with the three propellers but the bow would certainly indicate that it is a waterplane and it would explain the strange short vestigal wings.
Edit:
Ok i found it. Its the wreck of a Do 24 that was recovered from the Müritzsee thats halfway between Berlin and Rostock (type Mueritzsee in google maps then you should find it). In Autumn 1944 the three machines that were stationed there were attacked by american fighters. Two did explode directly and the third one was sunk to the lake. Thats the one we have here.
Source:
http://airshow24.com/tips_speyer.htm
