I'll post here the abbreviated version of an article of mine on re-entry and roll using a paddle-float. Maybe somebody knows of a better way to perform this back-up rescue? Unfortunately the images are nowhere on-line, so they can't be included here.
Solo at Sea: the Float-Roll Self-Rescue
This is a roll that in fact is no eskimo roll at all. Briefly put, after his wet exit the paddler fixes his paddle-float, fills it with air, does a backwards somersault into his boat floating upside-down, gets into the wind-up position, and rolls up with the float providing the leverage. Pumps dry and paddles on.
A detailed description
Here we have a right-handed paddler rolling up so his paddle and float in the end are extended on his right side. It would however be just as easy to roll onto the left side.
A wet exit. The paddler locates his paddle, fills his paddle-float and fixes it. He places himself next to his cockpit, facing the stern, and grabs the cockpit rim on the other side with his right hand. His left hand holds his paddle along the near side of his boat with the float to the bow, and also grabs the rim.
(Fig. 1 Getting ready to enter the boat.)
The paddler then pushes himself down with both hands and makes a backwards somersault that lifts his feet to his cockpit, puts them in and lifting himself with his hands seats himself. Having found the footrests and a normal knee-brace he grabs his paddle with his right hand also. The kayak remains upside down and the paddle is now on the surface along the left side.
The paddler moves his hands into the semi-pawlata position (left hand grabs the shaft next to the blade, right hand near the middle). He bends forward and up on his left side and then turns his paddle so that the shaft passes above his head. The shaft now lies at right angles to the boat and the left, empty blade rests on its bottom.
Fig. 2 The wind-up position
Only after the paddle has been properly positioned will the paddler pull down on it with his right hand. As the kayak turns the paddler must remain bent forward so his nose will scrape the deck in an arc from left to right. His torso will leave the water only in the end, its weight remain near the axis of the roll, and minimal force will be required. In the end the paddler will still be bent forward, now onto his right side, and leaning on his extended paddle with the float. A very stable position.
This method is easy and reliable: all through the development I have never managed to completely mess it up. I have always gotten upright albeit not always without a struggle - not if I've for instance failed to bend forward sufficiently or if I've straightened up too early.
This is also a quick way to get back up, if the paddle-float was filled before getting under way.
The best thing is that there is no unstable phase when the paddler would be sitting on top of his boat trying to wriggle his feet in. The center of gravity remains low and the end position is as stable as one can wish. In rough seas one can also roll up so that the float will lie upwind, not downwind. This is no problem as the method works well on both sides.
There is one potential problem: During the somersault the paddler will easily turn sideways if his PFD has much buoyancy. No reason however to go without one; the roll will just be less elegant.
As the boat is rolled with the spray-skirt open, some water will enter it. This will in fact make it roll more easily, as it then sinks lower into the water. The amount of water is nearly constant and pretty much the same as when the boat is first flipped upright and then entered using the paddle-float conventionally.
Were one to attach the spray-skirt while upside-down, the amount of water would be smaller. But I always run out of nerve before achieving this. Also, an untethered paddle might be lost while both hands are busy with the spray-skirt.
A few words on practice
This rescue requires the boat to have buoyancy: bags or bulkheads. It can however be practiced with one that has neither, or at least the somersault part if one makes sure the air inside doesn't escape. This however is much easier than one might think, although a small "sea" opening or a thick PFD will require more practice.
Practicing the roll itself will fill a boat with no buoyancy. Sea kayaks on the other hand can be rolled as long as one wants: they take in what water they will but float anyway.
During the roll two things are important: the paddle prior to pulling down on it must be at right angles with the shaft above the head, and one must remain bent forward all through the roll. The tip of the nose really should draw an arc over the foredeck from side to side.
If one feels there isn't enough leverage, one can also use a full pawlata grip.
I certainly don't mean it were better not to wear a PFD: it isn't. One can also achieve the ability to do fully upside-down re-entries by tailoring the lift of one's PFD or by choosing the inflatable type and not inflating it.
And last but not least: everything I say in this article only applies to the touring paddler out at sea in a modern sea-kayak. Things are quite different elsewhere, on white water or in surf for instance. I want the reader to understand this.