Think there is a copy of the original brochure on my desk at work so could find out on Monday for you. I have a copy of the front page so PM me your e mail addres and I can send it to you, can't upload it here unfortunately as its a 600kb PDF. The XR20 are lighter than the Vipers so about 270 kgs for the hull, engine will be a guess at 130 kgs, but add all the other bits as well.
This might work:
Have you seen this:
http://ospreyowners.webeden.co.uk/
Pete
