Nice video, great job on the replacement. Just one caveat for anyone thinking about doing the same: before replacing the box, check the foil you want to use, and the board the manufacturer suggests for it. Some (for example Slingshot) have the rear straps at the same position as the box, while most windsurf boards (including the XFire in the video) have the straps further forward. These wings end end to far back on the windsurf boards. Verified that by installing a foil box in and old freestyle board without moving it forward
.
I've foiled a lot with an old slalom board and a Slingshot Infinity 84 in the "C" position, and thought that worked ok. But since I moved to using a "D" position which puts the front wing 5 cm further forward, things are much more balanced, and pumping the foil in lulls is easy. I had never figured that out in the C position, since most of my weight was on the back foot.
Slingshot foils with track gives opportunity for foil positioning. Here is a video for putting foil box with tracks that could be adjusted for windsurfing.
www.seabreeze.com.au/forums/Kitesurfing/General/Surboard-converted-to-foiling-seems-a-no-go?page=1