It looks like we finally settled on how to replenish our lpg during the trip to Europe.
Our current setup in the US consists of two standard lpg tanks that you see at home used for bbq grills etc. Given the different fittings in Europe, the initial plan was to use the CampingGaz adapter that would allow us to connect a CampingGaz tank to the boat.
It seems that these tanks are relatively small, not used everywhere in Europe and also relatively expensive. Therefore, we decided to buy an adapter that essentially connects to the American tank and has a German fitting on the other side. That way we can fill our tanks in Germany (and maybe some other countries in that region). Don found this adapter at https://www.gasfachfrau.eu/de/produkt-details/product/id-118.html:
As we will be sailing to numerous other countries that do not use the German fitting, we also bought a set of Euro-Adapters that convert the German fitting into numerous other ones (https://www.gasfachfrau.eu/de/produkt-details/product/id-168.html):
Euro filling set
Adapter D1 D2 D3 D4
Filling Connection Nr. D1:
W 21.8 x 1/14″ LH filling device with a connection to external thread M10x1
GAS: Gas Vetta
Countries: Italy, Switzerland
Filling Connection Nr. D2:
W 21.8 x 1 / 14 “LH on filling device with connection W20x1/14” LH internal thread (according to EN 12864 image G1)
Gas: Liqui, Butane, Agip, Mi, Pibi gas
W 21.8 x 1/14″ LH on filling device with connector M14 x 1,5 external thread
Gas: Primus, Pibi, Kosan Gas
Countries: Norway, Austria, Portugal, Scotland, Switzerland, Italy, Sweden
Filling Connection Nr D4:
W 21.8 x 1 / 14 “LH on filling device with connection W21.8×1/14” LH internal thread left (Shell access to EN 12864 Figure G8)
Gas: Nordisk-Flaskegas, Calor-, Botto-, Esso-, Thermo-, Drachen-, Primus-, Butano-, Oban-Gas
Countries: Denmark, England, France, Netherlands, Italy, Austria, Switzerland, Spain
All we need to do now, is to find places that actually refill tanks from the US. That seems to be harder than one would think in some countries. We will buy tow new tanks in the US so that we at least pass the initial visual inspection.