Admin aside... Just think of the worst case scenario if you have to ditch, and cover all bases.
The Ferry will more than likely be going faster than you, and I wouldn't rely upon it as a safety net.
Everything is fine while the engine is running, but these things have a habit of stopping just at the wrong time. A few have done it in the past, and so far no engine problems...but...
Ramon, when he did the long flight from Spain to Tenerife had all sorts of safety measures, flotation suit, flares, radios, satellite trackers etc and a back up rescue helicopter!
Good luck if you attempt it, admire your drive, but please be safe [sMILING FACE WITH OPEN MOUTH AND SMILING EYES]