the 16m x3 is launchable from deep water (but must be pumped up to 7psi or thereabouts)... and it requires strong/hard swimming. If the leading edge is down in the water with the underside of the canopy facing you... my technique was:-
1) unhook completely from the chicken loop or fixed harness line.
2) get the bar with your left hand, then reach up to the depower strap and pull it from in front of you to right over your head...then
3) Swim hard and fast toward the kite.... when I mean swim, not a leasurely doggy paddle, but swim like there's a great white chasing you!!
4) the kite will then flip over so that the wing tips are up and it is resting on the "roof" of the canopy.
5) then with the kite directly downwind of you, swim AWAY from the kite, but to either to the left or right of the kite
6)the kite will then be in a position to relaunch.
7)sometimes it is necessary to pull on one of the lines to reposition the relevant wing tips
prior to launching, it is advisable to hook into the chicken loop.
Alternatively, retro fit a 5th line shift system YOU WILL BE AMAZED how much easier this makes steps 1-4. Basically pull on the red shift line, BINGO the kite flips onto its back without any Johnny Weissmuller swimming
It makes the process soooo much easier
When you prctice a deep water relaunch dont aim to do your first one on the horizon....keep it safe and so that your mates/other riders know where you are.