Before I got my first kayak, I’d take a lunch trip to a box store at least once a week, looking at kayaks. Wide ones, narrow ones—I had no idea what I was looking at. But it got me thinking, Are kayaks stable? And is a wider kayak more stable (than a narrow one)?
That was a while ago. Now I know that there are three things that affect kayak stability. But before we get to the specifics, let’s answer the question:
Are kayaks stable? Most modern kayaks are very stable for their intended use. Fishing kayaks are very stable platforms for fishing. Recreational kayaks are also stable for the casual enjoyment of paddling. And ocean and touring kayaks, on the ocean and cutting through the water, are remarkably stable kayaks.
But what most of us are really asking is what kayak is the most stable one I can get if I plan to do [blank] type of kayaking. And whether that “blank” is recreational, ocean touring, or whitewater kayaking, stability is affected by the same three things.
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What Affects Kayak Stability?
In general, stability is most affected by kayak width, weight distribution, and the shape of your hull. (We’ll get to hull shapes below)
But more specifically, there are three main factors that affect a kayak’s stability. They are length, width, and volume. Different combinations of those three measurements interact to create a kayak’s stability.
It’s a widely-held belief that a wider kayak is more stable.
But, is a wider kayak more stable? A wider kayak is generally considered more stable than a narrow one. This is largely due to it having more surface area to resist side-to-side tipping. All other measurements and paddling conditions aside, the wider the kayak, the more stable it will feel. Stability is simply a kayak’s ability to resist rolling and capsizing.
But stick with me, because simply getting a wider kayak to increase stability has its practical limits. And depending on what type of kayaking you want to do, wider isn’t always better … or more stable.
To talk about stability, we have to know what kayakers mean by stability. So let’s define the measurements that affect kayak stability the most.
Those three measurements we talked about—length, width and volume—are a kayak’s dimensions.
But why are they important?
It’s All About “Displacement”
The two main dimensions of your kayak are length and width, but the third measurement is a term called displacement (volume). And simply put, displacement is the overall weight of your kayak and its contents.
But more specifically, when you put your kayak in the water, some of the water moves out of the way to make room for your kayak. The more you load it up, the more water your kayak displaces. If you weighed that “volume” of “displaced” water, it would equal the weight of your kayak and whatever contents you put in it, including you.
That weight is your kayak’s displacement.
Kayak Length and Stability
Kayak length plays an important role in displacement (volume). Because for any given displacement (how much weight the manufacturer wants the kayak to hold), as you reduce the width of a kayak you have to increase its length in order to get the same displacement—i.e. load carrying capability (volume).
That’s why when you see those ultra-narrow racing kayaks, they’re also super long. It’s also why a short and wide kayak can keep as much weight afloat as a long and narrow one.
What is displacement length?
Your kayak’s length overall (LOA) is the stated length from the manufacturer. LOA is measured from the very tip of the bow of your kayak to the very end of the stern, rear. Then there’s displacement length.
Displacement length is the length of your kayak at the water line (LWL). It’s a lot less than your kayak’s bow to stern maximum length (LOA).
Displacement length matters more than overall length because it’s the most important factor in how your kayak performs. The reason is that it’s the surface area that will interact most with the water as you paddle.
Don’t worry, unless you’re an engineer you’re not going to have to worry about fatness ratio, but if you’re curious like I am…
By dividing the volume of displacement (weight of kayak and contents) by the length of displacement at the waterline (LWL), and then cubing it, kayak engineers have a scientific way to compare the efficiency of different kayaks.
It’s called the fatness ratio and it ranges from .6 for longer lightweight touring kayaks to 1.8 for really short and heavier whitewater kayaks.
Kayak Width and Stability
Kayak width is actually called “beam” in nautical terms. And the beam is your kayak’s width at its widest point. While kayak length generally determines how fast a kayak will go, and volume is tied to how much weight a kayak will hold, width is the biggest factor in what most people consider kayak stability.
How wide is a kayak? The average recreational kayak is about 28″ wide. Most recreational kayaks range between 25″ and 32″ wide. For touring kayaks that average width goes down to between 23 inches and 26 inches wide. Performance—sprint—kayaks are even narrower at 19″ to 23″ wide.
What is displacement width?
Kayak width is measured two ways:
- BOA – Beam overall – which is that manufacturer’s stated brochure number we talked about above.
- BWL – Beam at the waterline – which is the part of the kayak that’s touching water.
You might’ve already guessed that the more important measurement is kayak width at the water line, BWL. It’s the measurement that truly affects the stability of your kayak.
So then those stated manufacturer’s width numbers don’t mean much in practical terms for the performance of your kayak, do they? For that, engineers have another ratio.
L/B or L:W Ratio
The length at the waterline (LWL) divided by the beam at the waterline (BWL) is the Length to Beam ratio—L/B.
LWL/BWL = L:B Ratio
A higher number means a narrower faster kayak.
Typical L/B Ranges
- Whitewater Kayaks – 6.0:1
- Sea Kayak – less than 9.25:1
- Fast Sea Kayak– L:W ratio between 9.25:1 and 10.99:1
- Sprint/racing Kayaks – greater than 11.0:1
Volume is Designed Displacement
Back to our third kayak dimension number—volume.
Volume in a kayak is actually something called “designed displacement”. And it’s simply how much weight a kayak was designed to carry. All volume and designed displacement mean to you is, is there enough room and weight capacity to fit you and store all your gear?
If yes, perfect. If not, the kayak’s “volume” is not right for you.
And you can figure that out by looking at the weight capacity rating for any given kayak and then, more importantly, actually sitting in the kayak.
Yes, some kayak manufacturers will publish low, medium, and high or cubic ft. “volume” labels on their kayaks, but most don’t. Regardless, every kayak manufacturer has their own take on “high” volume. So the best thing to do is just sit in it and make sure it fits you.
Okay, I realize that was some rough, dry math…
But, now that we know what we’re actually talking about, we can talk about length, width and overall stability.
Advantages of a Wide Kayak
One of my first concerns as a beginning kayaker was staying upright, because I had this phobia of capsizing and getting trapped under my boat … upside down. And concerns over stability are why so many entry level recreational kayaks have an average width of 28 inches.
Are wider kayaks more stable? The quick answer is yes. Wider kayaks, generally speaking, have more side-to-side stability than narrow kayaks due to their ability to counteract sideways roll with increased surface area.
Some advantages of wider kayaks:
- Better side-to-side stability
- Better comfort in the cockpit
- More storage space for gear
- Easier maneuverability
But while a wider kayak can be better up to a point, depending on how you want to use your kayak and the type of water and waves you’ll be in, wider isn’t always better.
It would be tough to paddle a 5 foot wide kayak, but it would be good and stable.
So let’s get back to stability.
Kayak Stability Types
There are two types of kayak stability—primary and secondary kayak stability.
1 – Primary Stability
Kayak primary stability is how well your kayak initially resists rolling and capsizing when it’s straight up and down. How stable it is in calm, flat waters when you lean just a little bit to the side.
This initial stability is what most beginning kayakers refer to as the “stability” of a kayak, they’re talking about primary stability. Leaning a little too far to one side in a kayak with good primary stability probably won’t flip it over. But once you lean past a certain point, the kayak will quickly roll and capsize.
Kayaks that have good primary stability are meant for calm waters, lakes, and slow rivers. These are your wider recreational kayaks. They’re great to learn on because they resist capsizing so well.
2 – Secondary Stability
Kayak secondary stability is how well your kayak resists capsizing after you roll it past that “certain point” and far over onto its side. (Some kayaking veterans like to call this a kayak’s secondary “edge”) Practically speaking, it means when you lean far to the side, your kayak doesn’t feel like it wants to roll and capsize. It will actually track well and remain upright even far over on its edge.
Kayaks with good secondary stability make great ocean touring, sport and surf kayaks. Where seas are rough and waves are common use a kayak with good secondary stability.
Primary Stability vs Secondary Stability
If the best of both worlds did exist, a kayak engineer would’ve made it by now. Sadly, there are no kayaks that have both great primary and great secondary stability. You’ll have to choose which one you need more based on the waters and type of kayaking you’ll be doing.
- Primary Stability – used for calm, flat waters, learning to kayak, or kayak camping.
- Secondary Stability – Rough seas or waves, or long distance touring.
In order to talk more about kayak stability, we have to talk about hull design, because that affects both primary and secondary stability.
Kayak Hulls and Stability
Before you add anything to your kayak, it’s most likely just a big plastic or fiberglass shell. And the bottom of that shell—the part that makes contact with the water—is called the hull.
Kayak hulls vary between manufacturers and between different kayaks types. And the reason for this is that kayaks are designed to match different water conditions and different purposes, so they require different hull designs matched to those conditions and uses.
Kayak Hull Types
There are two hull design types—displacement and planing.
Displacement hulls are so-named because they displace water—move the water out of the way—as they’re paddled forward. They’re best for speed as their shape causes them to cut through the water as you paddle. Displacement hulls are great as racing and ocean touring kayaks.
Displacement hulls are generally:
- Less stable at rest
- Narrower and sleeker design
- Have pronounced points at the ends
- Accelerate quickly
- Easier to paddle long distances
- Better at cutting through waves
Planing hulls have flatter bottoms and ride on top of the water. They typically push water in front of them until they are up to speed and then they skim across the surface. Planing hulls are great for fishing kayaks because they provide a stable platform to cast and move around in the boat.
Planing hulls are generally:
- More stable kayaks
- More maneuverable
- Accelerate slowly
- Poor at handling waves
Kayak Hull Shapes and Stability
There are four basic kayak hull shapes. Each has different stability characteristics.
1 – Pontoon Hull
Pontoon hulls have an inverted rounded tunnel along the bottom. Pontoon hulls are the most stable kayak hull type and they provide great primary stability. Calm water, sit-on-top recreational kayaks and fishing kayaks use pontoon hulls for their excellent stability.
The disadvantage of Pontoon hulls is that they’re slow and lack maneuverability.
2 – V-Shaped Hull
V-shaped hulls are typically a planing hulls and look exactly like the name says—they’re shaped in a “V”. V hulls accelerate quickly, track better through the water, are easier to paddle long distances, and they’re fast. Ocean touring, racing and many recreational kayaks use V-shaped hulls.
But V hulls have some disadvantages. They’re less maneuverable and less stable than other hull designs.
3 – Rounded Hull
Rounded hulls are just that—round on the bottom. They’re considered displacement hulls, and they’re very maneuverable and easy to turn. Rounded hulls have better secondary stability, which allows the paddler to stay upright while leaned over. River and whitewater kayaks use rounded hulls for their superior maneuverability and stability.
The disadvantage is that Rounded hull kayaks are hard to keep in a straight line—they don’t track well. And in flat calm water they’re slow. Though this isn’t a really big concern because whitewater and river kayakers get their speed from the flowing water.
4 – Flat Hull
A flat hull is, well, flat on the bottom. Flat hulls are classic planing hulls. They have good primary stability, but poor secondary stability. So outside of calm water, the risk of them capsizing increases.
Recreational kayaks, fishing kayaks, and some whitewater kayaks use flat hulls.
Inflatable Kayak Stability
There’s one question I hear a lot that we didn’t really touch on in this article. And that’s because they’re in a class all by themselves.
Are Inflatable Kayaks Stable? You might be surprised to know that modern, quality-manufactured inflatable kayaks are incredibly stable. Oftentimes inflatable kayaks have wider hulls than hard shell kayaks. This and their superior buoyancy makes them very stable even in choppy water or big waves.
How to Improve Kayak Stability
Now that we understand all the components that go into a kayak brand’s stability, we can get to work figuring out how to improve your “kayak’s” stability. (those “bunny ears” mean that the solution’s not going to be all about the boat you’re in)
So, how to improve kayak stability? Kayak stability is different for every person and at every skill level. In general, you can improve your kayak’s stability by getting the right kayak, sizing it for your weight and height, adding a little ballast if you need to, and improving your balance.
How to improve stability in your kayak:
- Get the right boat – It seems simple, but it’s not always that obvious. If you’re going to run rapids, get a whitewater kayak (it won’t be all that stable). If you’re going touring in the ocean, get a longer sleek touring kayak made to paddle all day and long distances. And if you want to learn, have fun, and enjoy flat lakes, get a recreational kayak with a wide beam.
- Size it for your weight and height – If you weigh 250 pounds (ahem, that’s not me … okay, it’s me) don’t get a kayak rated for a displacement volume of 200 pounds. You’re going to ride low in the water, have a tougher time paddling, and you’ll constantly be worried that the slightest lean will fill your cockpit with water. In short, you’ll feel less stable. (don’t ask me how I know this)
Conversely, no matter what type of kayak you get, if you weigh 120 pounds and you get a 250 lb weight capacity kayak, you’ll feel less stable and more like the kayak is overpowering you when you paddle.
- Add some ballast – There’s nothing like an extra 10-15 pounds in your lap to make your kayak feel more stable. Even a small cooler with some drinks and ice will help. (At the least you’ll have something cold to drink after a hard paddle)
- Improve your balance – The absolute best, cheapest, and most satisfying way to improve your “kayak” stability, is to improve your own personal balance. Practice in your boat, but better yet get those core muscles tuned up. Situps, supermans, whatever you have to do, because kayaking is heavily reliant on rotating your torso. And “detaching” your waist from your upper body helps balance and stability. Stronger core muscles are how that happens.
NOTE: Yoga improves your balance greatly.
That’s a lot of info to digest, I know. But by now you should have a super good handle on all the factors that go into making your kayak more stable. And as far as the question of whether or not kayak’s are stable…?
Despite concerns about “tippiness” and whether you might end up under your boat instead of on top of it, modern kayaks are very stable. And sized right and properly selected for the type of water you intend to paddle, kayak stability will be more of a function of how much you paddle—practice—than what particular boat you’re in.