The first is an example of the 2-stroke back deck handroll.

The second is a forward-finishing sweep roll.

  A reliable hands-roll is a sweet, sweet thing.  With this capability, even the thought of losing your paddle and capsizing isn't so scary.  Although we're rarely called upon to do it (unless we're hand-paddling) it's a good thing to be able to do, if only for the peace of mind it'll give you. Ever have that 'paddle broken and you're upside down' dream?  Not a big deal, I don't need a paddle to roll, you'll say.

The good news is that the handroll is the fastest kind of roll around.  Boom, it's done.  The bad news is that it requires good form- that is, no sloppiness is allowed, and those of us who aren't all that flexible may experience limited success.

Like any roll, it's useful to be able to start from anywhere and have options on where to go- so to this end, it's useful to be able to roll on either side, coming or going, as it were.  I'll talk about 4 different types of handroll- essentially, Starting from your back deck and either finishing there or forward, and starting from a tucked-forward position and finishing either forwards or back.

Hand-rolling principles:

• Setup- just like any other roll, setup is important- and the objective of your setup is to get yourself up close to the surface, in a position where your hipsnap will be able to get you up to the point where the stability of the boat can help you.  Fortunately, it's perfectly acceptable to dog-paddle yourself into your setup position. :-)
• Hip-snap- just like any other roll, the hipsnap is vital- but unlike a roll where you have a paddle to lean on, in this case you'll have your hands and torso to work with- which means that the success of your hand-roll will be more reliant on a solid hipsnap than your paddle-roll is.
• Counterweight-  most rolls finish on a brace stroke of some sort, where the paddler has the luxury of using their paddle to finish things off if their hipsnap only got them 70% of the way up.  Because it's tough to maintain a working brace using just your hands, a different means of 'finishing' your hand roll is needed.  Instead of relying on a brace to finish a hand-roll, we instead make a primary goal of getting some part of our body across the boat early on- so instead of bracing outside of the boat, we're counterweighting the far side.
• Low-profile exit- because the time you spend with your head outside the gunwales of your boat and out of the water is time for gravity to act upon you, it makes sense to minimize this moment.  Rather than rolling to an upright sitting position (a luxury we can afford with a paddle) we will focus on rolling such that we sneak across the gunwale low and quickly- that is, we'll bring our head over the boat low over the bow or low over the stern before sitting upright.

From Back to Back, 2 strokes:

The 2-stroke back-deck roll begins in exactly the same position a back deck roll begins: upside down, with you lying under your stern, facing the bottom of the river.  As this is a vulnerable position to be in, the first thing to do is reduce your vulnerabilities- that is, pick a side, turn your torso toward that side, and reach the hand on that side up towards the surface, while bringing the other hand across your body, close-in, protecting your face, while reaching across towards the hand up at the surface.

Relax your torso and use this moment to sort of hand-paddle yourself as close to the surface as possible.  When you're happy with where you are, begin-

First stroke:  The first stroke, done with your top hand, is merely a vehicle to bring your bottom hand up toward the surface.  Do not try to use the first stroke to get your head out of the water- your head should be the last thing out.  Your top hand should begin at the surface and pull directly down, while your bottom hand should snake tight across your chest and up towards the surface, across your top shoulder.  At the end of your first stroke, your top hand should be low across your chest, with your elbow near the surface, while your bottom hand should be at or near the surface, reaching across the top of your chest.  Immediately go to the second stroke.

Second stroke:  Now that you're close to the surface and your bottom hand is at the surface, use the second stroke to do your hipsnap and to throw your top hand, elbow-first, over the stern deck.  Bring your head out of the water last.

From back to front-

Setup: Begin on your back deck by relaxing your torso and sort of dog-paddling or sculling with your hands to bring your head and shoulders as close to the surface on one side or the other of your boat as possible.  If you're flexible enough to get your head out of the water doing this alone, leave your head in the water, and keep on looking downward.

Sweep: Aggressively sweep your entire body along the surface of the water, going from stern to bow.  As your sweep reaches 90 degrees or so, you'll note that it'll feel natural to snap your hips in order to continue the sweep while still looking downwards.  (if you attempt to turn your torso to look up, you'll reverse your hipsnap and end up beneath the boat).  Continue the sweep all the way until you finish low over the bow.  As you approach the bow on your sweep, throw the arm nearest the bow across it, to achieve greater stability.  Do not take your face out of the water until your arm is across the bow.

Learning tricks to play with:

Hand paddles- if you have access to hand paddles, by all means use them to work out the way to make your hipsnap and body positioning easier.  Often I use hand-paddles to teach beginners how to roll this way before I teach them to roll with the paddle, it really does isolate your hipsnap and clarify for you what you need to do with your body in order to make this roll work.

Balance points- from an upright position, lie all the way onto your back deck, then experiment how far into the water you can put your head on either side.  Experiment with what happens if your outboard arm is fully in the water, versus how it feels if you try to lift it.  At the same time, experiment with how moving your inboard arm across your body and using it as a counterweight gives you a lot of stability.  For added grins, play around with your ability to sweep from this position to a finish on the bow.

Summary-

The handroll is not an inaccessible maneuver, despite it's reputation for being in the realm of experts only.  With the right kind of physical and mental flexibility, it's arguably easier to learn than the paddle roll- all you need to do is practice and believe, and it shall be yours.