If you want data try google. Search terms would be the name of the watershed or water body and the words "water quality assessment". You'll have to learn some biological and physical chemistry to understand what the numbers mean, but really all kayakers just need to stay away from is poo which is everywhere so we don't worry about it. Also, for us generally speaking dilution IS the solution to pollution. Particularly on the Potomac since it is such a large volume river.E.g., "National Water-Quality Assessment--Potomac River Basin" is about the Potomac and water.usgs.gov/nawqa is the main program page.
I'm not sure how the schools mentioned below have changed.
Disclosure: I am not an expert paddler. I am too cowardly to be a "good" paddler, let alone a great one. So don't take what you see below as the ultimate reference on kayaks and paddling. I have taken lessons from a few great paddlers, like Eric Jackson and Greg Barton. I have definitely made mistakes along the way. But I have learned a few basic tricks for efficiency and injury prevention.
Not all paddling schools and instructors are created equal, nor do all kayak instructors teach the same techniques. (I restrict this discussion to kayaks.)
I ignore here schools that only try to teach kayaking in less than an hour. A reasonable degree of mastery requires more time. Without that, you are limited to very slow, stable boats, under very easy conditions, you don't learn to play, and you will probably paddle very inefficiently and get sore. On the other hand, such lessons are the way many people begin. They then buy (or rent very expensively) those slow stable boats - and often feel, a month or two later, that they need a more playful and/or faster boat, to play or keep up with other paddlers.
An expensive lesson learned: on any subject, including sports, try to watch any instructor teach someone before taking a paid lesson; take a brief lesson with him or her before paying for a long expensive workshop, to determine if his/her teaching style is your learning style. You may learn best from demos, verbal feedback, physical guidance, or analysis, or by some combination of all of those. You may want a coach who addresses other issues, like other physical training and diet, or even a professional career. Pick an instructor who teaches accordingly.
Most U.S. whitewater kayak teachers advocate the "old school" style of motion endorsed by the ACA (American Canoe Association), which relies on redundant techniques to prevent shoulder injury: keep shoulders, arms and elbows down and arms forwards of the body. They rely on keeping the body on the front deck to let the helmet protect the head while underwater - which is great if you have the flexibility.
I think some ACA-trained instructors advocate limiting the range of shoulder motion too strongly for many people. Any time you use too much muscle tension or resistance to limit motion, you lock your muscles and joints in place, which greatly reduces your safe range of motion, making injuries much more likely. In addition, the muscle tension may itself break your bones, or tear muscles and ligaments. Try to stay loose. (But old school folks ARE partly right. If your shoulder is forcibly pulled into a high back position, shoulder dislocations and/or muscle tears occur easily, especially if your paddle is out to the side, and is pulled around by the force of the current, and especially if you have long, flexible muscles.)
"New school" instructors worry less about limiting range of shoulder motion. They may say to keep shoulders down, but not as much about keeping the arms forward too. This is a more athletic and effective approach, which allows much more effective boat control.
And many new school instructors argue that rolling upright as quickly as possible takes priority over keeping the head on the front deck during rolls, which may or may not be right for you, depending on circumstances and your flexibility. An alternate technique to protect your head is to bring your arm across your face - a bit risky, both for the uncovered part of your head, and for possible arm dislocation, but the best you can do if you aren't flexible enough to bring your head to the front deck.Kayak types and paddling techniques
Traditionally, "kayaks" (also spelled Qajak and Qayak) were boats created for arctic waters, that you sit inside of, with a top deck that sealed out the water, except the "cockpit" hole in which you sit, which is sealed betwee the cockpit rim and your waist by a flexible "spray skirt". Kayaks were built by stretching an animal skin, like seal skin, over a wood and bone frame. (Streching materials that are strong under tension around materials that are strong under compression is a very efficient and lightweight way to build a somewhat rigid structure, using minimal amount of materials.) Because you can sit very close to the bottom, and the sides of the boat do not need to be very high, even in the frequently rough waters of the North Sea, they can be more stable (less top-heavy) than traditional canoes, which are open on top, and kayaks can also be quite light. They were generally fairly narrow, and were often paddled using double bladed paddles, whereas canoes were usually paddled using single bladed paddles. Being sealed in also helped keep people warm in arctic waters, but kayaks are so much fun that their use has now migrated into warmer climates. In modern society, kayaks and other small craft are primarally recreational toys, rather than practical tranportation and hunting craft. I love to play with true kayaks, though mine are made of more modern materials. Coated nylon makes an excellent skin material, and modern composite materials, like carbon/kevlar/epoxy, are more abrasion resistant, where that is needed. Cross-linked polyethelyne is great for even more reselient whitewater toys. Neoprene spray skirts work extremely well.
To some people, "kayak" now encompasses a much wider range of boats. For example, many whitewater canoes are repurposed whitewater kayaks, in which the seat has been replaced by something you can kneel on. (Some canoes are sat in, some are kneeled in.) Canoeists love to point out that more skill is required to use canoes, especially if you use single bladed paddles, but in my mind, that is merely the extra skill required to control any poorly engineered tool or machine. It is true that people with bad backs often find it easier to kneel than to sit. Larger canoes can carry more cargo than most kayaks, which sometimes makes them a useful part of extended expeditions. Manufacturers refer to some sit-on-top boats of them as kayaks to take advantage of the popularity of the real thing. Some sit-on-top boats do have a deck in the sense that they have a sealed hollow air space for flotation, but you sit on the deck, rather than under it. That makes them less stable, as does the fact that you can not control the way they tilt by locking your knees into the sides of the boat, though some have "thigh straps". Most of them are quite heavy, slow and clumsy, in part because they need to be quite wide due to the higher center of gravity. (Though very lightly built, thin and unstable "racing surf skis" can be lighter and faster than most kayaks.) Sit-on-top boats are most favored by claustrophobic people who feel unsafe, sealed inside a true kayak. Sometimes even SUPs ("Stand-up-paddleboards", that you stand on) are called kayaks. In my mind, a "kayak" is still a decked boat that you sit in, and is the only small human powered craft that is much fun to use, though some others disagree. Sculling craft - that you row instead of paddle - may make much more efficient use of the muscles of the human body, but you can't see where you are going (unless you use mirrors, or complicated mechanisms that allow you to sit facing forwards), they are difficult to maneuver, and you can't play with oars as much as with paddles.
Kayaks are often advocated to beginners because you can learn the basics of paddling a forgiving rec boat kayak, and some of the wider sea kayaks, in a few minutes. Some of us are also much more comfortable in a kayak then a canoe, and are more comfortable using two bladed kayak paddles than one bladed canoe paddles. You can sit in or on one of the wider and more stable "rec boats" without fear of tipping, and paddle the boat by pushing and pulling, with alternating arms, without an obvious need for additional training. But this simplicity and initial stability can lead rec boaters into dangerous situations. They paddle further from shore than their skills are up to handling, or in colder water than their clothing is up to handling, or paddle alone. They may also be unprepared for tidal currents or are blown and pushed around by strong winds and waves, which are hard to fight in such slow boats. Some don't even wear a life jacket ("PFD") - they think it is good enough to have one in the boat, and then can't reach it after they flip, because it is carried away by winds or current, or don't realize how hard it is to put on while they are floating in the water. (Lay the jacket open on the water, and throw yourself, back first, on top - it takes practice.) In reality, under some conditions, such as when crossing a current, a storm blows up suddenly, a wave washes into or over you, or if you take the wrong stroke, any boat can tip, and it can be a matter of life and death that you know and have practiced how to right it, and get back in if you came out, and that you can also help others in your group do the same thing. You should also paddle in groups, and learn to rescue each other, if they flip and/or come out of their boats. I believe every paddler should learn to roll, and to help each other. Most paddling deaths could be easily prevented. Virtually every time you hear of a paddler dying on the news, they weren't wearing a life jacket or adequate clothing for both the water and air temperatures, were too far from shore for their skill levels, were paddling alone, and/or were drunk. Or they came out of the boat, and didn't know how to get back in. Most untrained kayakers have no idea how many times more efficiently they could paddle, how much safer they would be, and how much less sore they would feel, if they took appropriate lessons, and learned and practiced proper technique. Once they learn to practice proper technique, they can paddle boats that are enormously more efficient and more fun than rec boats.
There is a very important distinction between "displacement hull" boats, (such as sea kayaks, touring kayaks, some rec boats, some creek boats, slalom boats, and an older generation of "old school" whitewater and play boats), and "planing hull" boats (such as the most modern "new school" whitewater play boats, as well as ocean surf boats). The distinction starts with how water from in front of the boat is pushed out of the away as the boat moves through it, or the water moves around the boat - a rounded bottom displacement hull pushes it sideways into "bow waves", while a flatter bottom planing hull pushes it downwards. (They are not completely flat - they must bend or curve upwards at the sides and front.) V-shaped bottom cross section boats are mostly displacement hulls, but can plane if you are moving at very high speeds, such as are encountered in motor-powered speed boats and some sailboats built for racing. (V-shaped bottom boats are less stable, but they lean better and track (go straight) better. I hate them. Some boats with hard "chines" [corners in the surface curvature] are, like full V-shaped hulls, initially unstable when not in motion, and become more stable in motion, and have some "secondary stability" if you lean them enough to touch one of the secondary surfaces to the water. For skin-on-wood-frame and some purely wood, hard chines reduce required construction weight.) Regardless, nearby water is drawn into the circulation pattern. So, when you paddle forwards, a displacement hull effectively draws in water from ahead and from below the boat, and thrusts it sideways. A planing hull draws in surface water from ahead and from the sides, and thrusts it downwards - a partially reversed circulation pattern, in terms of what happens to the sides and below. Displacement hulls tend to be a faster than planing hulls. (But planing hull motor powered speed boats, and some sail craft, are faster than displacement hulls, because they lift most of the boat, especially the front, out of the water. When a kayak surfs a wave, planing hull kayaks can do the same, though not as much as a speedboat. In contrast, the front of displacement hull boats is lowered as you move forwards, because water from below has been pushed outwards and does not support the boat at as high a level.) The extra speed of a human powered displacement hull can be very important if you are racing on flatwater or somewhat rough water, or are trying to keep up with a group of fast paddlers. (Many racing surf skis, the fastest paddled boats, have almost circular cross section below the water, to the point of being very unstable, and are definitely displacement hulls.) But, as will be discussed below, in conditions where speed is not paramount, planing hulls let you keep the paddle and boat lean on the side, which allows for much better control, especially if there are significant waves or currents, and staying higher above the water also enhances your ability to surf big waves and holes without drowning in the foam, or getting stuck in holes. (A hole is a place where the surface current flows back upstream, usually created behind an object that the current flows over. Holes can be fun or scary. Mostly a whitewater phenomenum - sea kayaking has other dangers and play spots.) I prefer fast displacement hull sea kayaks, because they are almost effortless to paddle quickly, but prefer planing hull whitewater boats, because they are more playful.
Most whitewater playboats have fairly sharp edges - the chine at the sides, front and back of the boat, at or near water level. That allows you to tilt the boat, and use the paddle to push one side of the boat under water, which allows for many forms of play. Likewise, you can rock the boat forward or back, and initiate vertical moves. However, extremely sharp edges are sometimes difficult to control, as they catch and sometimes flip on currents, so the sharpest edge boats are not good for beginners, and sometimes not for advanced boaters either.
Forces generated at the front ("bow") of the boat is partially undone at the back ("stern"), as water from the sides or below come back together. If this happened perfectly and symmetrically, with clean smooth "laminar flow", and all the water came back to where it originally was, the effects of the water on the boat would cancel out - the boat wouldn't even slow down. But in the real world, some of the water has been pushed so far away, that it has less effect on the boat (fluid dynamics people talk of flow separation). In addition, the water moves fastest relative to the front of the boat, because the water tends to move with the boat towards the back, so that forces at the front dominate what happens. Of course, when the boat moves backwards, the front becomes the back and vice-versa; for simplicity we ignore this here.
The displacement hull water circulation pattern means that static bow draws (old style "Duffek draws"), where you plant the paddle far forwards on the side towards which you wish to turn, work very well, because the paddle catches the outgoing surface current, and also stabilizes the boat against tipping by the centrifugal forces generated by the turn. But on a planing hulls, this move actually functions as a pry, and tends to spin the boat out of control (especially if you expect it to act as a draw), or flip it (because the current catches the edge of the boat). The right draw technique for planing hull boats, sometimes called a "moving Duffek stroke", is to pull the paddle inwards next to the hip, even though it leads to a marginally less "safe" shoulder position. The resulting greater boat control, which means you go where you intend, is argued to be more important than using only "safe" body positions. (Eric Jackson said "Better boating is safer boating." I think he was right. Losing control is much more unsafe than a marginally less safe body position.)
Another efficient turning technique for displacement hulls is to lean outside the desired turn. The displacement hull circulation pattern pushes and pulls the water in such a way as to move the boat into the desired direction. It is an advanced technique, because it destabilizes you against the outside lean created by centrifugal forces associated with the turn. Furthermore, if you use the lean to turn downstream with respect to the main current, such as into an eddy, you eventually have to switch leans, or the edge of the boat will catch the downstream current and flip the boat. (BTW, leaning outside of turns is also taught in downhill ski racing.) In contrast, with planing hulls, you lean inside the desired turn, as on a bicycle, which takes advantage of the partially reversed circulation pattern to push and pull the boat in turn direction. At the very start of the turn, the lean does catch the edge of the boat, but it probably won't flip you because of both the centrifugal force and the fact that once you turn far enough into a current (e.g., at an eddy), the new current will stabilize you. Furthermore, your paddle is on the side you are turning towards, which gives you much better control over what the boat is doing - an overwhelming advantage of planing hulls in water with large waves or currents.
Using the turn technique appropriate to the boat hull type not only enhances control, but it keeps up your speed better through turns. Some of the older literature doesn't recognize the difference between displacement and planing hulls. I was once taught to use displacement hull turns on my planing hull kayak, which caused me to lose control, by an instructor who was more familiar with old school displacement hull kayaks. And, needless to say, regardless of hull shape, turning while you are at the top of a wave is easier than at the bottom.
There are of course exceptions to the rules I listed above. E.g., There are
planing hull slalom race boats and displacement hull whitewater kayaks, and there are
hybrid boats that lie somewhere in between. And there are many other
characteristics that distinguish various canoe and kayak designs from each
other. See, for example,
How to Choose a Whitewater Kayak
Beginners Guide to Kayak Terminology
Sea kayaks vs. other kayaks and canoes
Game Changers: Design Trends
For example, boats with more rocker (end-to-end bottom curvature) turn much better, but are much slower. I think sea kayaks should have less rocker, to the point of having a full-length waterline. OTOH, whitewater kayaks should be nimble (easy to turn). Other speed factors are length and width, at the waterline. Boats that have a waterline-length-to-width ratio of about 12 or somewhat more are much faster, but are tippier. Wider boats are slower. If they have sharp edges they they take a lot of practice to paddle - which also means they are more playful. Most sea kayak ads claim their boats are "stable and fast", which is utter nonsense. OTOH, surfing kayaks, which includes whitewater playboats, should be somewhat wide to surf better. A boat which has a very low volume front (bow) or back (stern) can be very difficult to control, if what you want to do is surf - but they do vertical moves more easily.
As noted, it is more or less true that the sides of a displacement hull are shaped to push water away, and the bottom is shaped to pull water towards it, and the reverse is true for a planing hull. So if you lean the boat over enough, so that the side becomes the bottom, and the bottom (as well as the top, if you lean it even further) becomes the a side, that makes displacment hulls act like planing hulls, and vice versa. For example, a deeply leaned planing hull becomes thinner and faster, and can cut through waves - a move sometimes seen in downriver races. People also sometimes put a boat on edge so they can sneak between two rocks that aren't far enough apart for a boat flat on the surface to fit between - as long as the rock on the side the body is on is BELOW the level of your body, so you don't bump into it. Likewise, a deeply leaned displacment hull, especially if the sides are tall and relatively flat, can plane sideways over the surface, so you can use draws or prys to pull or push the boat more efficiently across the surface, or turn more quickly. (In addition, the curvature of the sides of a kayak without much rocker curvature becomes the new rocker profile if you lean over enough - making turns even easier.) Leans are also used to initiate squirt turns and pirouttes. But most of these things requiring deep lans are expert level moves, which neither I nor anyone reading this page is likely to need.
Boats built by stretching a thin flexible skin over a lightweight frame (e.g., wood) can be very fragile, and do not have much resistance to abrasion or puncture. For the most part, they are not suitable for whitewater, or for departing from or landing on rocky beaches; for their protection you may sometimes feel the need to swim or carry them in to shore. Plastic resin boats, like polyethylene (cross-linked polyethylene is a little tougher, though a bit harder to repair, Royalex and others may be cheaper) are much more resilient, but are much heavier. They are molded in mass production facilities, and are mostly relatively cheap to make. Almost all whitewater boats are plastic resin. Whitewater boats can still be reasonably light because they are short. Composite boats (made from a combination of cloth materials, such as fiberglass, carbon fiber, Kevlar, S-glass, with a plastic resin, such as epoxy, polyester, vinyl ester, possibly reinforced by foam) are mostly somewhere in between, in both resilience and weight, though some of the lightest build composite boats (sometimes used for flatwater racing) are comparable to or lighter than skin boats. The rigidity of some of the composite materials also helps make them desirable for racing. In general, light boats are a joy to paddle. They are easier to carry. They are more responsive, and sit higher on the water, so they are faster and more playful. Both skin boats, and wood boats (e.g., epoxy coated marine plywood - the epoxy slows rot and adds impact resistance) are often chosen by people who want to build their own, though a few also build composite boats.
Some skin boats are "folders". There is a way to collapse and/or take apart the frame, and remove the skin, so that you can pack the boat compactly for transport or storage. They are generally quite expensive and are somewhat trouble prone, requiring frequent repairs, and most of the existing designs are fairly low performance boats. I find the idea quite appealing, and tried to assemble several different types of folder that people were selling used (I have bought almost all my boats used, for economy), but lacked the physical strength to complete the assembly. They also tend to be advertised as being much easier and faster to assemble and disassemble than they really are. ORU has made some folders out of nothing but a creased skin, like Origami. While none of the boats of theirs that I have seen have been high performance, and I don't own a folder, the idea still sounds wonderful.
Inflatable kayaks can be even more compact, but are very limited. They tend to have very inefficient shapes, flex a lot, which adds to the inefficiency, and tend to be quite clumsy.
There have been a few sea kayaks that break apart for shipping or storage. Typically they have 3 compartments - front, rear, and passenger.
Sea kayaks generally have partially sealed storage compartments, which are great for expeditions and camping, though skin-on-frame boats usually don't. However, the bulkheads eventually leak water, in part because they must have small holes to allow the air to expand and contract as temperature changes, and in part because the seals around those bulkheads eventually leak. So anything you care about should be in sealed storage bags (dry bags) - though those all eventually leak too, but you do what you can. If you aren't putting anything inside (there are generally elastic deck lines that you can hook or tie small things into), you still want inflatable bags to keep out the water - I prefer dry bags that inflate too. Again, they eventually leak too, but again, you do what you can. Inflatable bags are a good idea for most other kayaks, to add flotation if they flood. It is very important that all gear be stowed so as not to move, e.g., by filling available space with inflatable bags. Stuff that moves around makes the boat very hard to control.
Touring kayaks are essentially short sea kayaks, but a little shorter, with less storage space, and are slower, but are lighter and cheaper. They may be quite adequate for you, if you don't have to keep up with fast paddlers, and you aren't on an extended expedition that requires a lot of food, water and gear. Even rec boats, properly used, can be fun economical boats, if used within their limitations. But it may be difficult to keep up with some clubs if you don't have a full blown reasonably fast sea kayak. At one point I tried to paddle a whitewater boat with such a club. It was a slalom racing boat (I don't race, but outdated used slaloms are very cheap), but it still wasn't nearly as fast. Even more important, I had a shorter and heavier paddle than I should have - safer for rocky whitewater, but much less efficient. I became quite sore. I could have managed better if I were a very well conditioned athlete, but, as it was, I needed a faster boat and a longer, lighter paddle.
Comfort and fit are extremely important in kayaks. To a large extent you "wear" them more than bigger boats. Locking your knees and feet into a boat gives you much more control over what it is doing. While adjustable foot pegs, adjustable thigh pads, adjustable backbands and seat positions can help, the only real way to test comfort and fit is to try them. In addition, on long trips, many people feel they need to be able to take their feet off the foot pegs, and stretch out, which is not possible in all boats. If you want to be able to climb back into your boat from the water (you should be able to, for safety, in sea kayaks and touring boats used out of swimming distance from shore), be sure you can do so before buying a boat. Depending on the shape of the cockpit, and any obstructions, it can be more or less difficult. If you want to be able to do a re-enter and roll, it is best if the cockpit rim and spray skirt are such that you can put on the spray skirt quickly while under water, to avoid flooding the boat when you roll. Your weight (with gear, if there is a lot, as there might be on an extended and/or camping expedition) can radically change the way a boat behaves. Ideally, you want your weight (and gear weight) to be in the middle of the design "ideal weight range". If you are too light for the boat, the ends of the boat may bounce up and down in the waves, especially if you have a fair amount of rocker, which is very inefficient, and you may also have trouble initiating vertical moves (mostly used in whitewater play, but sometimes used in open water too). If you are too heavy, the boat may sink, or almost sink, and it will be slow and hard to handle in waves and holes. As mentioned before, I like a front deck that is high enough in the region immediate under my knees to allow me to bend forwards. But I like a rear deck that is flat enough for me to relax by laying back on it.
Many kayakers play with "trim", by adding weights or cargo to the front or rear of the boat. For example, if there is more weight in the front than the back, the front of your boat sinks into the water a bit. This means it is hard to go straight. For a sea kayak, it also means the back of your boat moves more in wind and waves from the side, because the front is more "anchored" by the water, so the boat tends to turn into the wind. The reverse is true for more weight in the rear. The trim also depends on your body weight distribution. I personally prefer a neutral trim, meaning, I don't want to have to adjust for a tendency to turn, but a lot of other sea kayakers prefer boats which turn a bit into the wind. And people often place more gear in the front or back to adjust trim. Sometimes they even add extra weight. Boats with high decks in the front and rear also respond a lot more to wind; which is one of the reasons I don't like such boats at all, even though they can sometimes help keep waves from splashing you. The way I see it, kayaking is a water sport, and I expect to get wet. Fighting wind and waves is silly. Trim also influences how easy it is for the front and rear deck go into intended and unintended vertical moves.
Incidentally, people have been designing boats that have most of the discussed variations and features for many thousands of years, possibly millions, by other hominid species, like Neanderthals, though that is controversial. Design features have been discovered, forgotten and re-discovered many times, though the oldest boats have long ago rotted away, so that, as with all ancient history, archeological finds can easily change current conceptions about the past. For example, among the ancient stretched-animal-skin-over-wood+bone designs of the north arctic regions, there were fast displacement hull war boats, big fat boats that could transport a whole family inside, boats that looked and acted, on a small scale, somewhat like the Viking long boats of a later era, small maneuverable boats designed for hunting sea mammals, or which could carry a slain walrus upon their decks, and even a few small boats that to my inexpert eyes resemble modern whitewater play boats. Within the sea kayak community, some of the older designs, such as "Greenland" style boats, have recently become popular, attracting an almost cult-like following, especially among people who build their own boats, though in my mind, Greenland boats are somewhat suboptimal, because too much of the front and back are above the water, shortening the water line and increasing cross section to wind. There have also been many variations in paddle shape and construction. The ancient arctic boats, whose designs are sometimes still used today (including very lightweight, elegant designs, which require minimal materials to build), were typically paddled with using slightly reshaped sticks - which can be surprisingly light and efficient on long voyages. (I love the elegance and efficiency of my Greenland paddle, though I have a modern carbon fiber wing paddle, which lets you accelerate much faster for sprints, and is slightly more efficient on long paddles, though only because it is built slightly lighter.) For that matter, other "old school" boats have also enjoyed a resurgence, as people have come to enjoy paddling a variety of craft, using a variety of techniques.
It is most efficient to move using the muscles of the human body in a variety of ways, so on long trips, you should vary your paddling style. Rather than only using the muscles that make you move, and leaving all the others completely loose, it is better to stabilize some joints against excessive motion, so other joints move more efficiently. Virtually all modern paddling instructors advocate using spinal rotations about the waist, using your core muscles (abdominal, lower backs, legs) to move your upper body, and the paddle with it, from side to side, and little or no motion at the elbow and shoulder joints. It is called "torso rotation". This is better because your core and lower body muscles are much larger and potentially much stronger than your arm and shoulder muscles, and are therefore less likely to be injured. If you keep your shoulders low, this method also protects your shoulder joint, which is relatively easy to dislocate, especially if you are very flexible, and the relatively weak muscles of the shoulder cuff, which are relatively easy to tear. You also get much less sore, and can paddle much further and faster, without getting tired. It works - very well! That said, I've seen a fair number of paddlers with a history of prior spinal injury re-injure their spines in beginning level classes pushing torso rotation - they need to be very careful about spinal rotations. I believe people should be asked about prior back and spine injuries before being pushed into using spinal rotation. Perhaps it also makes sense for most people to move to full range of spinal motion gradually, rather than in one lesson. For those who don't have spinal problems and want to develop this technique, let me warn you that most paddlers who think they are using torso rotation barely do so at all - or they stop doing it after a few minutes: learn to watch where your belly button is, and make sure it moves as much as you can make it move.
Most ACA-trained instructors advocate a one hand paddle control technique, and short, half-length strokes. They keep a firm grip on the paddle with one hand, so it is rotated by that hand, and a loose grip on the other, so where it rotates by slipping. They also advocate taking the paddle out of the water mid-stroke, next to your waist, so you don't waste energy lifting water, and so you can take more strokes in less time. For me, it is much more efficient, and comfortable, to keep a loose grip on both hands (which I call zero-hand control), allow the water to orient the paddle, and to do full length strokes, especially on long trips. I guide paddle rotation by the path of the paddle in the water - straight or gradually curved line motion makes the paddle act like a parachute, and creates the most efficient possible push against the water, whereas more sharply curved motion, such as a slight outwards push at the end of the stroke creates, causes the paddle to "feather" (turn) sideways in such a way as to minimize interaction with the water. That outwards push at the end also avoids lifting water. With loose handholds, the distinctions between paddle shapes become much less relevant - e.g., you paddle or roll with Greenland sticks, flat bladed paddles, scooped blade paddles, and wing paddles, with very similar technique and efficiency. The British Canoeing organization materials mention this superior technique, more or less, as one alternative technique, and it is also frequently used by Greenland style paddlers, though most still use one-handed control. However, the ACA-advocated technique of using half-length strokes works better for brief high speed acceleration sprints, such as paddling up a rapid or catching a wave, because it lets a strong paddler use his or her strength to move more water more quickly, because you can generate faster short strokes. In addition, short strokes let you use support strokes (see below) better, because you can't press down on the water as well when the paddle is behind you. In principle, strokes in which the paddle is kept approximately vertical and next to the boat are much more efficient for going forwards and backwards, though on long trips it is sometimes more comfortable to vary that technique. Strokes in which the paddle is far from the boat are generally best reserved for turning and surfing.
To clarify, the handholds should only be loose enough to allow free rotation. Never let go of your paddle. Your paddle is your life. Even outside the boat, you can probably swim faster by using the paddle as though you were still in the boat. Just as you should almost never wet exit - you are almost always better off inside the boat, which provides a lot of flotation and protection. I had to train myself to stay calm enough to do that. I have learned that in emergencies, panicking usually just gets you in more trouble. Staying calm usually lets you find a way out. That's something that is often useful to remember in outdoor sports. To some extent, learning to stay calm requires practice too.
The loose handholds completely eliminate the need for a different form of paddle "feathering" - where the working surfaces ("blades") of the left and right side of the paddle are built or set to be rotated with respect to each other. The water will turn the paddle as it needs to be efficient. On my adjustable-feather paddles, I sometimes do create such a slight (5 degree?) rotation, so that each end of the paddle enters the water already at the optimal angle as I reach forward for a new stroke, but it isn't a big deal for non-competitive paddling. Some people claim that feathered paddles reduce air resistance, especially when paddling against a strong wind, though I haven't found that to be a major effect for me. Feathered paddles are important for competitive slalom racing, which I don't do, because it helps you not touch the gates with your paddle, which loses points. Some people also find it easier on their bodies to use "offset" or "bent-shaft" paddles, in which the hands are on a length of the paddle which is positioned forwards of the blades, but I haven't found that particularly advantages for my body. The only significant differences I have found between paddles for long distance paddling, for my body and paddling style, are in length and weight. In particular, for long distance sea kayak paddling, I want a paddle that is just long enough to comfortably do off-side bow draws. In addition, you want the lightest paddle that isn't in danger of breaking.
I think British Canoeing (was called BCU; North American Branch: Paddlesports North America) advocates better and more up to date paddling techniques than ACA, but ACA dominates the U.S. instructor certification scene. If you can find British Canoeing classes or "BCU" classes, I suggest you do so. However, taking ACA lessons is much, much better than taking none. I don't know anything about USCA classes, but suspect they are mostly aimed at competitive racers.
Many paddling instructors (including those following the ACA syllabus) teach "braces" - support strokes (which push down on the water to avoid tipping) from the start. Support strokes are very hard on arms and shoulders and probably cause many injuries. In addition, if you angle the paddle a little bit wrong, braces will pull you under. I say reserve support strokes for where they are needed - rolls, certain specialized surfing maneuvers, and breaking out of "window shading" (in which a wave breaks over the side of your boat, causing it to roll continuously). If you keep your body centered over your boat, accomplished partly by staying loose at the hip, partly by actively moving your body center closer to the centerline of the boat, you rarely tip. If you lean over in order to execute a brace, that will shift your weight sufficiently to the side to make you need that brace, and to feel that you can't do with it. Stay loose, and properly centered, and you probably won't need the brace in the first place. (That may not always be enough for upper level whitewater - which I don't do. I learned that I was creating the need to brace by bracing unnecessarily from instructor Scott Coulter, while surfing a low level hole.)
There are also compound strokes, where the paddle follows a more complex path, and stroke combinations, where, for example, a sweep on one side initiates a turn, followed by draws on the opposite side, which may be static, drawn inwards, or continued into a forward stroke, then feathered outwards and forwards, flowing into the next draw, without the paddle ever leaving the water. I sometimes like to use an over-the-bow stroke, where, I begin a a draw on one side, continue the motion over the bow and back into the water, continuing into a pry on the other side.(On a really short whitewater boat, the over-the-bow stroke can stay in the water!) Leans can help a lot, as with any turn. With a strong enough pull, you can bring the boat more or less vertical into a cross-bow piroute; see also the end of here. (I wish I could do that!)
Some paddlers constantly rock side to side as they paddle, even when going straight. This is inefficient, both because you are moving the mass of the boat, fighting buoyancy (which creates a "righting moment") and because you make waves. On flatwater, it is probably most efficient to keep the level; in waves you may want to allow the boat to rock somewhat with the level of the water surface. These effects are most pronounced on boats with relatively flat bottoms. Likewise, you should not constantly rock forward and backward when going straight. You turn your body as you stroke (primarally at the waist if you have no spinal problems), but your body stays upright, or, if you can without discomfort, leaned forwards (which is most efficient, when you are paddling forwards). (Some people have to stay leaned back, because they aren't flexible enough to do otherwise. Of course you lean backwards when paddling backwards.)
Some sea kayaks have rudders or skegs to help you turn them or stay straight. They are said to be especially useful while paddling through in wind and waves, in that you get much less tired, because you don't have to continually correct your direction, or maintain a continuous lean - in fact, racers have told me that it is more efficient to turn with a rudder than to lean. But both are fragile and trouble prone structures, which require great care when coming to shore or paddling in shallow water. They add weight, and skegs sometimes create leaks. I prefer to hold my paddle off-center instead. Even if you do use a rudder or skeg to help, it is very important that you be good enough at turning to retain control of the boat if they fail, because they will eventually fail.
I wish my sea kayaks had foot pumps, though they add weight and complexity too. So much easier and faster to use on the water than hand pumps. Furthermore, if your boat substantially fills with water, as often happens during a re-enter and roll maneuver, and sometimes at other times, it can be nearly impossible to empty your boat with a hand pump while at sea, especially if the waves are washing over you. Some people manage by keeping the pump against their body, inside the spray skirt hull, but that is awkward at best, and would be very hard in the big waves where you are most likely to flip. This would be most important for my low volume skin-on-frame kayak, which I love because it is thin, fast and light. But it is impossible to re-enter it at sea except by a re-enter and roll maneuver. All other re-entries flood and sink the boat. For the most part, boats like that are roll-or-die boats. I have a reliable paddle roll. But should I ever come out of the boat at sea, a foot pump would be a big safety plus. Some day I may add a custom neoprene spray skirt, to replace the nylon one built to fit it. With neoprene, I could do a re-enter and roll without filling the boat with water, because I could attach the spray skirt while under water - the nylon skirt is too awkward and slow. It would also be nice and considerate of my fellow paddlers if it had a strong enough front deck to perform T-rescues, though that too would increase the weight.
Paddling in a forwards leaning position is much more efficient. So another consideration that might apply to you: If you have a high front deck over your knees, you can bend them more, which makes bending your body forwards much easier for some people, with limited forward bend flexibility. You can also paddle more efficiently if you pump your legs a little, which requires a high deck too.
Most group lesson whitewater boating instructors entertain more than teach, pushing you into the thrill of whitewater rapids as soon as possible, and rely on those redundantly "safe" body positions to hopefully keep you safe. But many new schooler instructors see themselves as serious athletic coaches who aim to train serious athletes, often competitive athletes, so they concentrate on fundamentals before allowing you to advance with sloppy technique. They may make you spend at least a few days mastering proper technique before pushing you into moving water, arguably a better approach to safety, though it may not appeal to casual boaters.
Pick whichever philosophy appeals to you. New school teachers worked best for me, later augmented by lessons from a number of sea kayak instructors, but philosophies vary. Many modern teachers, especially sea kayak instructors, and British Canoeing instructors, try to take the best elements of multiple teaching and paddling philosophies. Many of the best instructors have been serious competitive athletes, and learned efficient techniques in the process - but by no means all great athletes are great teachers, especially to those with a less athletic background. Teaching too is a skill which often needs to be trained and practiced. Find an instructor whose teaching and paddling style works for you. Once you have learned good skills, practice them regularly, so you don't fall back into bad patterns of motion.
To anyone who has taken even low intermediate level lessons, which is about the most I have done, it is painful to watch so-called paddling experts on television, including the leadership of many prominent conservation organizations, as they lead "expeditions" on-camera. You know that they could substitute one efficient stroke for every three or four they take (yes, the difference between efficient and inefficient technique is at least that great), if they practiced torso rotation, used strokes more appropriate to the design of the boat or paddle they are using, understood how to use their body weight more efficiently, loosened their grips, and stopped bracing on every stroke. I'm sure that to real experts, there are other efficiencies that are painfully absent on typical television shows about paddling.
Needless to say, always carry adequate supplies, including safety gear, food and water, for your trip, and keep it in an accessible location while at sea.
One last thing that I have been very slow to learn: Paddling is an athletic activity. So are other sports, like hiking and ice skating. If you train as an athlete, and work to increase your strength, endurance, and flexibility, paddling will be much easier, and you can do more things. Athletic training is another area where lessons can help, and where instructors vary a lot. Good training exercises should make you somewhat sore, for as much as a day or less, if they are to be effective, though you can definitely over do that. Some medical experts worry about DOMS (Delayed Onset Muscle Soreness), a condition of long-term inflammation which delays or prevents healing. You may have to learn for yourself whether that pain is a good thing. In any event, shorter term muscle soreness, lasting at least 15 minutes or so, always occurs if you have done much exercise, because of metabolic waste products. Optimal training regimes vary person-to-person, but a typical optimal training regime might include 5 days/week of aerobic (cardio) exercise, 3-5 days/week of abdominal training, 3 days/week of other strength training, and 1 or 2 days/week of rest. Do different exercises, and work on different parts of your body on different days. For me, but not everyone, many sets of 8-10 exercises, until I exhaust myself, is most effective for strength training. Since my interests are in endurance sports rather than maximal strength or well-muscled appearance (at upper training limits, which I am not at, strength and endurance actually trade-off against each other - but even at lower limits, you only have so much time and training capacity, and the extra weight that comes from maximal strength training and bodybuilding hurts performance in endurance sports), I mostly work at strength levels that mostly don't push my strength to its limits - but every once in a while I do push a bit - usually before my day(s) of rest. And for me, interval training (3 minutes slow, 1 minute fast, repeated many times) helps improve my aerobic capacity and endurance. Over-training is counterproductive; you break down your muscles without repair and rebuilding. Likewise, eat as an athlete eats. Maintain a balanced diet, drink plenty of fluids. Consume a little extra carbohydrate before exercise, to supply the energy needed. Consume extra protein afterwards, to help build muscle and reduce muscle soreness. If you are diabetic or prediabetic, you probably need less fat and carbohydrates and more protein than most people, and you may need to monitor blood glucose levels - ask your doctor. After training, be sure to stretch the muscles that you have exercised, unless you are hypermobile (too flexible), in part because muscle training shortens muscles. (Muscles stretch best when they are warm - e.g., after working them out.) When exercising, I need to stretch a couple times a day to avoid this problem, but that varies a lot by person. When you can, soak in a hot tub afterwards, which helps again with muscle soreness - though some people advocate a sauna or even a cold bath to do the same. Cold also reduce inflammation (and I have successfully used it after bruising tissue), and cold is widely used to promote healing of more serious injuries, but I refuse to try such an unpleasant idea as a cold bath after normal exercise, when a hot tub works fine for me. You can also choose to work on other athletic skills, like balance, agility, and reflex speed. Do learn effective injury prevention techniques - e.g., practice gentle falls and collisions; a lot of paddling injuries occur while carrying the boat over rough terrain, and such injury prevention techniques carry over into many activities. Don't stiffen your body too much when danger threatens, but let your body collapse more gradually to absorb impacts.
Above all, enjoy yourself! Getting efficient equipment and learning efficient technique can contribute to your enjoyment, but don't take all this so seriously that you can't have fun.Kayak descriptions