No, a 12m kite would not be enough to pull a ship.
You sail world record for sail circumnavigation. The average speed record for a circumnavigation is nearly 30knots. Kitetender only goes about 20 knots. So even if your boat were the same size (a dinghy) you would need either a bigger kite and/or hydrofoils to go the required speed. Since you will likely want a bigger boat than a dinghy ( you said "ship"), and you want to go faster than kitetender, you will need a much bigger kite.
Look at tandem (two person) paragliders. I think they come up to 44square meters.
I googled "ASV rescue kite" and this was the third thing to come up:
http://wakewindandsurf.com/editors-choi ... chts/16266
If that looks too expensive to you, why are talking about a record-setting circumnavigation?
You don't want a kite, you want a magic carpet.