This a fairly new boat but I have been attempting to build one, it is a g/f, a top, bottom and two inner full length ribs, pre assembled with motor mount, prop tube, and rudder. The firdt kit, rudder post fell off when inserting rudder, I followed the supplied instructions after fitting motor, servo etc cutting out openings in port wing you are asked to test boatin water to check self righting. Mine promptly filled with water 3 leaks between port wing and inner compartment 2 leaks right at front of hull no easy access due to motor mount.
Kit was changed by my supplier ingnoring instructions cut openings and tested, Hooray no water leaks how ever the rudder post fell off, carried on with install coming to fit of skeg between prop tunbr and hull found supplied part was to small, checking against planfoubd thatthe tube was at a too steeper angle, 12mm to far rearwards and motor mount to low and rearwards also. Graupner has been contacted and they are going to supply part so that I can fix.
So I suggest to any one who might by this boat to the following
1 check for water leaks before any thing else
2 check measurements of prop/motor positions
3 Graupner recommend UHU Plus glue if this was used during "factory Pre assembly" suggest you do not
Pastit
PS I know of at least one other with similar faults, and latest is that drilling holes for saftey loop the top hull flexed and the cock pit flew off!