I live in Denmark, and I'm sure that we bought the (used) sub's from Norway. Maybe that's a lead you can use in your investigation? I'm sorry I cannot give you the exact answer.
Yours Sincerely, Robert Holsting, Denmark
1/81 SSBN Ohio Class scratch builder, more at www.robse.dk
"Never be afraid to try something new; remember that it was amateurs who build Noah's Ark, and professionals who build the Titanic"