Before you buy a sit-on-top kayak (or any kayak, for that matter), you should take stock of where and how you plan to do most of your paddling. Most kayaks can be used for a variety of activities, but understand that no one kayak excels at every activity. Choosing a boat means mulling over a long list of characteristics and compromises-be wary of anyone who tells you about the "best" kayak overall-there is none. There are, however, a few guidelines to help you decide which boat is best for you:
Length and width affect speed and maneuverability. When it comes to speed, it's all about surface area. A long, thin line allows paddlers to slice through the water quickly-a real advantage if you plan on touring, but a drawback on twisty rivers. A 17 foot-long kayak will go much faster than a 9 foot-long kayak, but a 9 foot-long kayak will turn easier than a 17 foot-long kayak. A narrow kayak is faster than a wide one, but wide kayaks tend to be more stable (depending on hull shape).
Hull shape affects performance. Depending somewhat on width, flat or smooth-bottomed kayaks (U-shaped) have more secondary stability, while keeled kayaks (V-shaped) have more primary stability. U-shapes may feel tippier at first, but stay stable in moving water (rivers, surf, etc.) while V-shapes feel most stable in flat water. The tri-form hull of most sit-on-tops combines both primary and secondary stability with a long center keel to keep you going straight, and two "shoulders" that act like sponsons for secondary stability. This tri-form hull generally sacrifices a little speed, but adds a lot of stability (which is great for cross-over sports like fishing or diving).
There are lots of different hull shapes, but basically V-shapes encourage a boat to go straight (good for touring), and smooth bottoms encourage a boat to spin (good for surfing, kayak polo, or river running). Whether or not a kayak goes straight is referred to as "tracking." You'll want a kayak with good tracking to cover distance on flat water, but you'll want less in whitewater. Chances are, for recreational paddling, you'll want a kayak with a keel (some kind of V-shape on the bottom), so you can travel more efficiently. If you expect to spend equal time on flat and moving water, consider buying a short kayak with a keel (it's all a continuum, remember).
"Rocker" is another term used to describe hull shape. Think of the keel as something you'd notice on a kayak cut in half. Rocker is most noticeable on a kayak cut cross-ways. A kayak with a lot of rocker would look like a "U" in a cross-ways view. A kayak with little rocker would look like a line. Keeping in mind the idea of surface area and water displacement, you'll want a lot of rocker (one round point touching the water) for maneuverability, and you'll want very little rocker (a long, thin line of points touching the water) for touring. For recreational paddling, pick something in between.
You can paddle a tandem kayak alone, but it's not easy. Do you plan to paddle solo or tandem? This is one of the most basic questions you'll have to answer. While one person can paddle a tandem alone, it requires sitting in the rear of the kayak while ballasting the front. The kayak will move, but not at its optimal level. On the other hand, it's a lot of fun to go out with a partner, often safer, and usually cheaper than buying two boats. There are a few tandem sit-on-tops that have a jump seat between the front and rear seat wells. This seat arrangement makes it possible to balance weight for better performance when paddling alone, and may be a good option to try if you want to paddle both tandem and solo.
Your body determines how the kayak will perform. You probably wouldn't buy new pants without trying them on first. The same rule applies to kayaks. When you test paddle, you aren't so much looking for mechanical failure as you are trying to get sense of how the kayak fits. It goes beyond just height and weight-people carry weight and proportions in different ways, and these differences translate into how you balance in a kayak. You can always learn how to work with different kinds of kayaks-experts tend to balance better than beginners-but know that it will take time and practice, especially if you decide on a specialized kayak.
Other things to consider. There are a few other things to think about when choosing a kayak. Where will you store it? Can your garage or basement hold a 16 foot-long kayak? How will you transport it? Do you have roof racks or would you rather put the kayak in a truck bed? Even color choice is important. Do you want to be seen, or would you rather be camouflaged? Considering these issues early on will ensure you enjoy your kayak for many years.
Summary. For a beginning or recreational paddler (someone who wants to do a little of everything), a shorter (9-13 feet), wider (28-30"), keeled, roto-molded kayak is a good choice. You should be able to get a brand new set up (a sit-on-top, paddle, and backrest) for between $500-800.
Safety, safety, safety. Check weather conditions. Always follow the boating rules of the area you're in. Brush up on self-rescue-first in calm, warm, shallow water, and again in more extreme conditions. Invest in appropriate clothing for your climate. One advantage of sit-inside kayaks is that you can shield yourself from some of the elements, while sit-on-tops leave you more exposed-dress for the day. Most importantly, WEAR YOUR PERSONAL FLOATATION DEVICE. There are great PFDs designed specifically for paddlers. Buy one that fits well, and always wear it while you paddle. Sit-on-top kayaking is safe and fun, but all water sports involve risk. Please don't take chances.
What about paddles, anyway? The great thing about recreational paddling is that it takes very little equipment. Next to the kayak itself, a paddle is your other big choice. Many of the rules that apply to choosing a kayak apply to choosing a paddle. The first rule is that there are none. There are all kinds of fancy equations people have come up with to choose the right paddle for you. The reality is, there are lots of things to consider. How long is your upper body? Your arms? What's your paddle stroke like? How big is your kayak? What type of paddling activity will you do most? How does the paddle feel? What's your budget? Do you really want a $300 carbon fiber paddle for your $400 roto-molded kayak? Listen to the advice of trained paddlers around you, then make your own decision. Find a dealer who can provide both the product and service you require. A good dealer can be your best resource.
What else do I need? Like most sports, the sky's the limit if you want add-ons for your kayak. Other accessories include a backrest to help make paddling more comfortable, scupper stoppers to keep your self-bailing cockpit drier, and dry bags are important for storing gear. You can also buy accessories for navigating, diving, fishing, and more. If you plan to take your kayak on a car top regularly, you'll find a hard rack system worth the investment.