The best brace is a good catch.
Long Post Alert: If you really want to work on your rough water skills, then you need to be able to change your balance dynamic from one that is reactive to one that is proactive.
Reactive balance habits are an indicator that you are taking what the sea throws at you and trying to correct. The challenge here is that even if you get very good at juggling this way, it's likely you'll also soon drop a ball and swim. The other downside is that this is not an efficient or fast way to paddle. Think of bracing as the equivalent of slamming on the e-brake. It makes sense to keep you from flinging yourself off the cliff. Fine. But taken critically, it also means that you misjudged your conditions, equipment or balance and messed up. Not fine if you take this seriously and consider yourself a racer.
If you approach rough water skills from the perspective of connection, you have nothing to react too. You are connected powerfully to the ski, and the ski is connected to the water. To get a solid connection however takes some serious work, starting with the realization that a surfski is a craft not designed to balance for you... that is absolutely your job. But a ski is designed to listen to you. They are very rewarding, and demanding because they are incredibly reactive to all the inputs that a paddler sends their way. If you tell your ski you want to go for a swim, it will listen to you. And if you tell it to drop in on awkward 2' boat wake for a nice little side surf, it will listen to you... if you are sending it the right message.
The point here is that it's your job to tell the ski exactly what to do, and to get good at rough water you have to develop the fluency in your craft to say exactly the right thing to it all times. No. Matter. What.
A few observations from having taught hundreds of people to paddle over long periods of time and seeing them develop from shaky flat water duckies to downwind screaming eagles:
1. The first thing to go when a paddler gets in trouble is foot pressure. It is a natural reaction to not knowing what to do, so the legs come back (fetal position of fear), the pressure on the foot board disappears which takes it off of the back of the bum. When this happens... BOOM! You are no longer connected to your ski, and when you take that precious next stroke, you pull yourself off balance or into the water. If the boat is jerking / rolling sharply left and right this is a tell that your footwork needs work. ProTip: Focus on keeping the pressure on your heel all the way through your stroke until you make the next catch. This has the added benefit of keeping your hips rotated forward and in position to make a better catch. Work your shift in foot pressure like a clutch. Smooth, but firm.
2. The paddler is the biggest liability in the ski. If you ever watch a ski fly downwind without it's jockey, you'll know that it's just fine without you. If you watch a paddler who struggles in rough water, you'll quickly see lots of body parts moving independent of each other. It honestly hurts to watch because it telegraphs so loudly. Each movement you make sends a message, so part of the paddler's technique focus needs to be to reduce the number of sequential, independent movements to just one movement that is repeatable over and over and over again no matter what the water is doing. ProTip: Practice paddling in ultra slow motion in figure eights and in increasingly rougher water. Go from boat wakes, to rebound to haystacking, confused seas. When you can paddle beam in slow motion with breaking seas and 40kts of wind and not feel the need to rush the catch - you are definitely connected to your boat and the sea. Savor this, for great white shark blood now courses through your icy viking veins and even the orcas fear you.
3. Do not paddle with your arms. Paddle with your torso and legs. One helpful tip is think of your arm as a stabilizer for the catch. Repeat after me: The arm does not move after the catch is made. The body rotates and pulls the entire boat past the arm as the paddle tracks slightly away from the boat to either side. If you pull that arm from the elbow, you pull the paddle through the water. Very sloppy. Very unstable. Your power and the generation of forward movement should come from the torso being used to power a lever. The arm becomes the pole of a pole vaulter. Its job is to act as the lever held perfectly in place by the bicep and tricep, and the torso is the engine pulling against it consisting of your big muscle groups: lats, traps, gluts, rhomboids, quads, abs and hamstrings. ProTip: Imagine that your elbows no longer work from the time you make the catch all the way to the exit, and you're using your arms nearly locked and forcing yourself to pull the boat past the paddle locked in the water.
4. If the torso is where your power comes from, make sure your hips and your shoulders are locked together and rotate together. Think of two hinges on one door. If your shoulders are rotating independently or faster than your hips, you are not only whipping the stroke (which can make you more unstable), you're also putting your fine shoulder muscles, ligaments, joints and cartilage at risk because of the extra movement when under power. I know many paddlers who burn out their bodies from this issue. They get stronger, a little faster, and then BANG! Injury to a rotator cuff or a tear to the rhomboid or another small muscle. Why? Because the shoulder group was moving under power and not protected by the torso. If the torso drives the movement, the shoulder doesn't move very much until the paddle is fully out of the water (recovery phase of the stroke), and is not under the load of the catch. ProTip: Stand in water groin deep, and focus on making your hips and shoulders turn together, like a door hinge. You'll know you're doing it right when you feel the pressure on the heels of your feet corresponding the power that the torso is making.
5. Get the paddle out fast. The paddle is incredibly powerful, and can absolutely pull you into the water if used incorrectly. In rough water, the most valuable real estate in the ocean is from in front of your footboard to your knee - after that it's irrelevant. Focus on getting a powerful, clean catch that happens close to the ski, and then have the exit well under way by the time the paddle is at the knee. If you leave that paddle in too long or it tracks to closely to the boat, you will not only put undue stress on your shoulder group, you will also destabilize the boat. ProTip: Never let your push hand drop below the horizon in front of you. This will help you keep the paddle in the correct pitch, and prevent you from destabilizing yourself at the exit. The exit should feel crisp and fast - like a flick - not thick and heavy like the catch.
Sorry for the book, hope this stuff helps.
Nicholas
FasterFarther.com