Bill,
I sent many packages to/from the US to NZ using the 'land/water' transport method.
I'd usually take it to USPS and ask them the cheapest way to get it there and typically the response was, 'as long as you don't mind it taking 4-6 weeks, we can ship that box by boat.'
I'm not sure how sending it from Germany would work, but the land/water thing was always the cheapest I found.