I am working with a GPA friend to produce the complete hand cranck mechanism for the GPA.
Please let me know if you are interested to such a complete device.
The more who are interested, the lower the price.
The expensive thing is the casting part.
You can also mail me privat:
bobassel@xs4all.nl
Also available the rare and hard to find water propellor bearing holders.
Perfect steel replica., one available, and with more interested, maybe more can follow.
Reg. Bob