Before you start adding seats, skirts, mounts, pedal drives, cleats, bungees, hatches and all the other features you’ve come to love about your kayak, you have the hull.

A kayak’s hull is its bare-bones form, and it’s usually dressed up before even leaving the manufacturer. When you really look at them, you’ll notice that no two hulls look the same. Sure, they sometimes look similar, but kayak hull designs can vary drastically – and there’s a reason for this!

While each brand has its own unique style of designing kayaks, hulls are shaped to fit specific purposes. An obvious example would be comparing a whitewater hull (commonly short, rounded on the sides, and with a curved bottom such as that seen in a Pyranha Kayak) to a sea kayak hull (usually long, pointed and with a flattened bottom). It’s easy to tell that these kayaks are meant for different things, and you can probably guess some of the reasons behind the designs as well!

Kayak hull designs can vary drastically – and there’s a reason for this!

Hull Shapes

While basic hull designs are by no means limited to any set group, we do notice that there are four common types. These include rounded, v-shaped, flat and pontoon hulls, though it’s likely you’ve heard them referred to as other names in different places.

Rounded Hulls

As the name implies, these hulls have rounded edges, giving the kayak a ‘torpedo’ shape that results in increased speed because of less water resistance. Rounded hulls usually make for more maneuverable kayaks as well and commonly have more secondary than primary stability (see below for explanation of differences in stability).

V-Shaped Hulls

Compared to rounded hulls, these hulls have a sharper ‘V’ shape that allows the hull to better cut through the water, making them more effective at tracking in straight lines. These hulls are generally fast as well and sometimes considered ‘tippy’ as they offer more secondary than primary stability.

Flat Hulls

Flat hulls are used for a surprising variety of purposes, ranging from play boats to fishing kayaks. Based on factors like length, width and curvature, flat hulls combine stability and maneuverability. Flat hulls also offer great primary stability.

Pontoon Hulls (AKA Tunnel)

Stability is the key feature of pontoon hulls. Kayaks with these types of hulls combine the primary stability of a flat hull with the secondary stability of a rounded, resulting in the greatest stability available. While these hulls generally lend themselves to decent tracking, they aren’t known for their speed.

Primary Vs. Secondary Stability

Other than the basic shape, kayak hulls vary in the ways that they curve (or don’t). This can be in either the sides or the bottom of the kayak, and is referred to as chine and rocker respectively. These curves, or lack thereof, affect a number of factors when it comes to performance – the main one being stability.

Kayak stability is broken down into two sections: primary and secondary. Primary stability refers to the initial steadiness of the kayak on flat water, whereas secondary stability refers to a kayak’s ability to stay stable when tipped on its side (which is useful in poor water conditions).

Often, kayaks that are very stable in rough water feel tippy in flat water and vice versa. Manufacturers tinker with a number of factors to find the perfect balance of primary and secondary stability for each boat’s intended purpose. For example, a kayak intended for coastal fishing will be designed to consider the primary stability needed to fish but also the secondary stability necessary to handle choppy waters.

Chine

Chine is best defined as the way the bottom of the kayak meets the sides, determining whether or not the kayak looks rounded or boxy. A hard chine means a more angular meeting while a soft chine refers to a more rounded one.

Harder chine hulls are known to track slightly better and offer better primary stability but also provide a flatter surface for choppy waters to push up against – thus these boats are more prone to tipping in bad water conditions. Hard chine hulls are also popular for play boats because the sharp edges catch waves better and make it easier to perform tricks. On the other hand, soft chine hulls are better at providing secondary stability and known to generally be faster.

Of course, soft and hard chine are simply the extremes – an enormous number of multi-chine hull designs fall on the spectrum somewhere between the two.

Rocker

Rocker is the curvature of the hull from bow to stern. The name rocker comes from the fact that the more rocker a hull has, the more likely it is to rock from front (bow) to back (stern). More rocker allows for greater maneuverability because the bow and stern have to face less resistance as less of the boat is in the water. For this same reason, hulls with more rocker are less effective at tracking than hulls with less rocker.

In fact, a kayak with a flat bottom (no rocker) will track best as the bow and stern will have most resistance in the water (which prevents easy turning). Like a hull’s chine, kayaks can have any amount of rocker and can even have rocker only in the bow but not the stern or vice versa.

Primary stability refers to the initial steadiness of the kayak on flat water, whereas secondary stability refers to a kayak’s ability to stay stable when tipped on its side (which is useful in poor water conditions).

Is That All? 

Design symmetry, weight positioning, hull materials, water entry line and other more specific features (like sponsons or keel lines) are some of the other factors that manufacturers take into consideration when designing a kayak. However, knowing the basics about hull shape should help you make a more informed decision on which kayak will best suit your needs and purpose.

As always, if you have any comments or questions, share them below – we’d love to hear what you have to say or answer any questions you may have. Thanks for reading and happy paddling!

– Joseph @ACK

 

26 comments

  1. My husband and I are 60 years old and looking to buy kayaks. We will be using them in calm creeks with a few small rapids. Any input on what type of kayak we should consider would be appreciated. Thanks!

  2. Ok….I have only been in one kayak ever and it was from the military rec center. It was fine as we just went across the sound and back. I loved it so much that I’ve talked him into getting 2. I’m only 5″1 and my biggest concern is stability. We want to fish and just maybe paddle down the river for fun. I’m the the most gracefull and I’m an average swimmer. What’s best for me? Now my husband is 6″5. He just cares about the fishing part and feels as long as he has that covered them the river will be fine. What’s your opinion?

  3. Joining this conversation a little late but … I like to get out on the small rivers and streams near my home in northern Wisconsin. I’ve been searching high and low for a sub-9 foot boat with the chops for class III PLUS a modicum of tracking for the stretches in between the rapids. Any ideas? Thank you!

  4. Hey I am 18 years of age, male, 6 foot tall 235 lbs. I live in western PA and plan to do fishing with friends and just kayaking recreationally. So I need a kayak that can be versatile enough to fish on rivers, creeks, and lakes as well as just kayak for the fun of it with friends. I need maneuverability, speed is optional, durability, and lots of storage. Also room as I am a larger man. My budget is anything around 800 dollars

    1. Hey Alec,

      The best kayak that comes to mind given the factors you mentioned is the Feelfree Moken 12.5! It’s got a capacity of 419 lbs and great storage for your fishing trips, and it tracks well/has great stability for recreational paddling. It’s also right at your budget at $799! Check it out here.

  5. What kind of a hull design and rocker/non-rocker would you recommend for trying to surf small……..3 to 4 foot rolling waves……not breaking waves. I would guess I need something fast enough to catch the waves, but don’t know about the rest of the design needed.

    1. Hey Gladys, thanks for your question! The type of kayak you want depends on what you plan to do with that kayak – recreational paddling, fishing, whitewater yaking? Here is a short video that may help you decide on a kayak design: https://www.youtube.com/watch?v=98u0AVqQlt8 Once you narrow down a type of kayak, (a sit-on-top is a great choice because they’re the most stable and easy to get in and out of), call our customer service team at 888-828-3828 (Toll free) or email us at customer@austinkayak.com to chat more about brand options.

  6. I am looking for a kayak. I am 69 and love photography. Most of the time I will be yakking alone. So I want something stable. I won’t be going in fast moving water (or at least hope not too). I plan to go to the Keys and some of the rivers in Florida to kayak. What should I look for in a kayak? Length, hull, stability, durability, etc.

    1. Shirley, we apologize for the delay. For photography, we certainly recommend kayaks with stability since you will be focused on other things while sitting and may even want to stand up from time to time. Any of our fishing type kayaks offer more stability than most other kayaks. You can find those here: https://www.austinkayak.com/subcategory/210004/Fishing-Kayaks As a photographer myself, I enjoy the Feelfree Lure because of the high seat, ability to stand with ease and stability. However, I also like the hands free aspect of Hobie Kayaks: https://www.austinkayak.com/brand/5/Hobie?k=hobie Hope this helps. If you have other question, don’t hesitate to contact our customer service team at customer@ack.com!

  7. would rocker bow of 10″ and rocker stern of 12 ” be considered allot of rocker? ? Kayak is 18′ 3″ in length. Would this affect the tracking much? Thank you,
    Kerry

    1. Hi Kerry, From what I can see it seems like this is some sort of touring canoe or kayak as it is so long. With that in mind, the rocker numbers you gave me sound like they are normal – you should be good to go!

  8. My 12 year old paradize 13 foot kayak bit the dust so I’m looking for another kayak. most of the kayaks I’m finding(Malibu Two XL,Perception tribe13.5) have a pontoon bottom. I need a 13 foot dual sit-a-pon with a v-shaped bottom. We paddle around the Keys. The Bic borneo looks like it has a v-shaped bottom but I can not find one to look at(live near chicago). Suggestions ?

    1. Hi Stephen, we recommend looking into a flat or pontoon hull for maximum stability while fishing. The Diablo kayak line is one of the best on the market for fly fishing/kayak fishing. You can check out our selection here.

  9. I want to build a “boat” strickly for fly fishing in ponds & small lakes, (No waves except from wind and no current.), It will be a one man boat and I want it as light as possible so I can use my truck and no trailer. I would like to be able to stand up to cast but be able to paddle with my kayak paddle sitting down, so I do not want it too wide. (Probably between 32 an 36 inches. I figure about 11 feet long. My question is what is the best hull design? I have had many boats and read alot about hull design but really would appreciate your advice. Thanks

  10. Thanks Joseph, you have really explained the basic consepts very well. Where the manufacturers trick us with some of their designs is when they use combinations of these concepts in different parts of the hull. I was particularly interested in your explaination of primary and secondary stability. I had always thought primary stability was stability in the upright position and secondary stability was the kayak had better stabilty when it was leaned on a side. I suppose the result is the same.