While my boat is smaller, 90% of my launches are from the back of an anchored boat. Assuming kite rigged (my lines never come off except for tuning every couple of months), 1) flake lines carefully into water letting current/wind take them downwind (yes, they can tangle); 2) clip chicken loop to short line off a stout stern cleat (to avoid bar getting caught on stern or cleat or fishing rod holder) 3) pump up kite ( I use a bravo battery electric at the stern of my boat, but started with standard kite pump, as electric pump allows more attention to kite and lines - I've tangled them around the throttle, rod holders, etc); 4) leading edge down, let kite drift downwind. 5) I normally launch kite while still attached to boat (I am hooked in, but also chicken loop clipped to stern leash) - standing on the stern, grab board and go.
I reverse the process to collect kite. Sail to stern leash, hook to chicken loop, land kite, recover board, then kite. In deep water, this is slighty more cumbersome, but swim kite to boat, deflate and then haul aboard. Now wrap lines carefully once kite brought to boat so ready to go next launch.
I can normally be launched and riding in less than 10 min! NO SAND!!! (WARNING - Anything that happens on land can happen with boat launches - I have bent a bar, ripped off 2 rod holders and flaked out lines that I had tangled leaving a fully powered kite 75ft downwind that was not following the plan. But I have increased my kiting hours significantly. Anchoring over sandbars makes this process a bit easier, but is not required.) Enjoy!