Note
Another step forward (?) toward a map reader usable for more than 1 event. Larry Berman said the price on the Nordenmark MTB-O map reader was $90 last year. (Yikes.) I read a comparison in The Australian Orienteer of 4 different models, all of which look very sturdy, with a price to match. It's hard to justify that kind of expense for ~1 competition per year.
So I took my old pair of aerobars from when I did triathlons. I removed the springy wrist rests leaving only the diamond-shaped frame and mounting hardware. If I mount it right-side up, then maybe the map won't rotate. So I mounted it upside down.
So far, so good. The aerobars attach pretty firmly to the handlebars. Now to the map mounting portion. I have the idea of suspending something round and loosely attaching it to the aerobar side tubes. Then, the map case can attach to the rotating piece.
So far, the mounting apparatus I have is a bobbin gripped by rubber bands around the tubes. It present a bobbin-sized surface to the map case, about the size of a nickel. I could attach a map case with a loop of duct tape from beneath the case to the top of the bobbin.
Sail effect: unknown
Stability of the attachment; unknown
Compass mount: unknown
Aerobar mount: satisfactory, *and* movable from the road bike to the MTB with allen wrenches.