Okay,so I have broken 3 rigs while windfoiling in as many years. When all 225 lbs of me gets catapulted hooked in... well sometimes the mast breaks. It was all old equipment, possibly sun burnt so my bad. On a positive note I eventually figured out how to get in.
Open the boom clamp and slide the top mast down into the sail pocket below the boom cut out then re-clamp the boom. Now take your up-haul rope and lash the mast sections together at the clamp. Mind your fingers getting pinched as the gear bounces in the waves and be wary of carbon splinters! You may be able to water start it but I up-hauled by grabbing the mast. I was glad to be on a big stable board at that point.
After one explosion I actually managed to foil back a couple miles down wind to the launch site. I have not seen this anywhere before so I thought I would share this. The picture was taken Saturday; it blew 20+ all day and this happened early on. Fortunately my old Naish 4.5 has an adjustable head strap and I could rig it on a longer mast and keep sailing!