Eeeek! The spar has punched through the end of the pocket.

This is pretty simple to repair, some webbing (like you find on bag straps) and a sewing machine are all you need. I chose 1.5 inch wide webbing and a '60 bonded Nylon' thread. This is man made fiber so it won't rot.

Cut the webbing to the right length, approx. 6 inches for both side, thats a single 12 inch length. To anchor the ends of the webbing I needed to open up the original spar pocket, there is a line of stiches down the bottom edge. Unpick these:

Then I sewed the ends of the webbing to the side of the original pocket. I used a straight stich, then a small zig-zag back over it.

Here is the first end attached:

Then I sewed the other end of the webbing to the other side of the pocket (the black material on the right in the photo). Then I closed the original pocket back up with a line of stiches.

Here I am sewing down both sides of the pocket. The thread is going down through the webbing, both layers of the original pocket (which I have just sewn back together) and the webbing on the bottom.

Here is the finished repair with the spar back in.

A guy on the beach said that the same thing happened to his Arc, the repair cost him a fiver, well, mine was about 1 pound and a bit of time and effort. And most importantly I got to poke around inside my Arc which taught me a few sewing tricks that I'll have to use on my next kite :-)

And here is the Arc 630 in flight with a close up of the repaired spar pocket. Sweet.

Something I found out, but don't really have a section for is the aspect ratio for the following
S-Arc: Around 3.8
G-Arc: Around 4.5
F-Arc: depends on size, from 6,5 to 7,5