I still think this can be done. This just isn't the right place to find the answer.

I, too, would start with CAA, though perhaps not the local office.

How about a broker who handles many lines of commercial insurance? Who insures the car when it is on the ship?

If that doesn't do it, there is an Expedition Portal where people write about driving around the world or some set of it. A search or a question there should find the answer.

Try these people: http://www.tourinsure.de/englisch/index_e.htm

Found them with a quick Google...