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Choosing a Sea Kayak


  It is often said that paddlers 'wear their kayaks'. This is more than a figure of speech because the degree of control you exert over your kayak as well as good paddling experience depend largely on your body contact within it . As such, the choice of your kayak should hinge first on the right body fit and comfort and second on your skill level or intended paddling style.
To use an analogy; You will run further in comfortable 'boots' than in top of the line 'running shoes' that give you blisters after the first mile.
By the same token, if you are a tall paddler with a larger upper body build and 13 shoe size you may find it difficult to enjoy a 21" wide sea kayak that is too confining and that won't let you relax or take your mind off paddling for a second because it feels too 'tender'. If, on the other hand, you weigh 150lb, a stable and wide kayak will feel too 'loose' and you may find it difficult to bring the kayak to speed or to maneuver .


Choosing a sea kayak to fit you and your needs doesn't have to be difficult but it often is. It is hard to choose the right kayak, if the only hint of the fit that the manufacturer discloses is the maximum capacity and even worse, the volume in gallons ! (Do you know how many gallons you and your gear occupy? Just think how this would sound if you were buying a car).
Performance indicators and hydrostatics in particular are closely guarded 'secrets', or are not even known by the "designer". The fact that they are not telling you everything should tell you something!


As a builder, I am sure that you want to know everything there is to know about the kayak you will spend your time and money building and paddling. For this reason, I am providing complete technical specifications AND line drawings so that you can get a feel for the kayak and make an educated choice. The Kayak comparison page displays all the designs side by side for a better perspactive as to their size and scale. Builders interested more in the 'technical' side, can check out the kayaks' hydrodynamics such as wave and viscous drag as well as the total drag coefficient.


The best way you can start this kayak matching process, is to look at the suggested paddler weight range for each kayak design. Since there is a good match of body weight to height, this is a very good indication of fit. For example, the Cape Ann Storm has a span of 160 to 230 pounds, which means that if you are in this range, there is a good chance that the kayak will be comfortable for you, and just as importantly, that it will handle well. The optimal performance figure, in this case 200lb, is the ideal loading. This means that the kayak will be submerged to the designed waterline (DWL). For the vast majority of kayaks and paddlers this match is a lucky draw since paddlers are never told this.
The 'sinkage' tells you how much stuff you can put into the kayak for it to sink one inch. For example, if the Storm is loaded with 200lb (ideal loading) and you add 92lb the kayak will submerge an extra inch. All in all, the kayak will paddle OK but its overall performance and speed are reduced and a 292lb paddler would just feel too squeezed. That is why the recommended range goes only up to 230lb, not to 292lb.

Never select a kayak only by its maximum capacity. It is tempting to say: "Hey, I can really load this one up!" It is just a manufacturer's little secret to sell one kayak to as many people without regard to paddling performance. All it really means is that the kayak will not sink with that weight, but you might as well paddle in a bathtub because the craft will be severely overloaded and lose precious seaworthiness at that!.


The next important thing about a kayak is the front height of the cockpit. This determines how well you can get in and out, how your feet are going to fit, how much you can bend and stretch your knees, and how dry the ride is going to be. A higher cockpit makes entry and exit easy. You will really appreciate this in tough landing and launching spots or even on beaches when you need to time the waves and punch through the surf in a hurry.
A higher cockpit means less water in your lap and in the kayak. You can move your knees to stretch your legs or to change position in the seat without a struggle. Imagine having your legs locked for hours under a low deck with no space to move them. Sitting with stretched legs feels comfortable for a little while but cramps are sure to follow if you cannot get good circulation. You can easily lower your 12.75" deck by installing Minicel knee braces but how do you add space under an 11" coaming?

An important measurement is also the rear height of the cockpit. Comfortable cruising and touring kayaks need higher, solid back rests so that you don't feel like you have been sitting on a stool but instead in a comfy chair with good lower back support. It isn't an issue when you go paddling for 15 minutes but when you are out there for a while and want to 'lean back' and enjoy the scenery, you want something solid.

Some paddlers prefer snug cockpits and spray skirts to gain advantage in rough water while others like larger opening to enter and exit the kayak gracefully. Since this is a matter of personal preference, two or three cockpit shapes and sizes are included with each set of plans so that you can customize the kayak to suit your body type and your desired paddling style.

The next step in choosing your kayak is to determine how you plan to paddle it most of the time.




Recreational style paddling

I would define recreational style as any paddling that doesn't require much bracing, excessively leaned turns or any rolling, and is done in reasonably good weather and sea conditions. This generally means gentle wind, little current, smooth water or low chop, and swells with orderly wave action. The vast majority of paddling falls into this category. You want to be able to relax and enjoy 'hands-off paddle' activities such as fishing, birdwatching, or photography without feeling too unstable.

Under these circumstances, the necessity for a tight fit in the cockpit and bracing is minimal and the cockpit opening and height can be quite large for easy entrance and exit. Heavy knee bracing under the deck is largely unnecessary and hip plates need to hug the hips only loosely. The back rest can be made large and higher than the rear cockpit for comfort and good support.
Both the wider Cape Ann and the Cape Ann Double are comfortable and stable touring kayaks for medium weight to large/ tall paddlers and are well suited for these types of activities. The harder chine Expedition design is a high performance kayak but it behaves very well in this respect as well.
Just because a kayak is suitable for recreational paddling, it doesn't mean sluggishness and poor handling. Even recreational sea kayaks need to be swift when crossing shipping channels, river estuaries, or avoiding careless boaters and fishing vessels. Things can happen really fast on the ocean and you want a dependable kayak to zip away. With the Cape Ann's smooth acceleration and high cruising speed you can get safely out of the way and 'recreate' while everybody in your group is catching up. The Double is faster still and has a solid seaworthy feel to boot. You will not be be 'inching' away but 'footing' ahead of the paddling crowd or towards your destination by every stroke.

Adding a rudder to long waterline kayaks greatly adds to the paddling comfort and maneuverability in wind and rougher seas.
There is a lot of squabbling about rudders and skegs in the kayaking circles. It is a fact that most commercial sea kayaks in the USA have them installed. A rudder or a skeg is a convenient trim tab to enhance directional stability for difficult conditions as well as a safety feature when you get tired and don't feel like fighting the sea every paddle stroke. It doesn't matter whether the kayak rides like on rails or turns on a dime, sometimes you just want to cruise alongside your friend and spend more time chatting than maneuvering or get through narrow winding channels of a salt marsh without dislocating your shoulders on 'sweep strokes'. A rudder is a great 'tool' for that. I encourage novice paddlers to install it but also to improve their paddling skills to reduce their reliance on it. There is no rule that says you should or shouldn't have one. It completely depends on what your kayaking ambitions are. If you don't want it, you don't need it! If you have one installed, it is always good to know it is there, should it be needed.
I design my kayaks for good directional stability without the need for a rudder, (the long Double being an exception), but shape the kayak sterns to easily accept it for paddlers who would like it.





Advanced paddling

Even as a beginner, you may want to be able to venture out into rougher seas and enrich your kayak handling 'repertoire' with advanced bracing, Eskimo rolling, or wave surfing skills. For these activities, it is wise to select a seaworthy design that will respond well in marginal situations and can be relied upon to perform predictably.

Paddling in rough conditions also dictates a smaller cockpit (for a smaller and tighter spray skirt) as well as for sufficient kneebracing support. Low form of the backrest is good for unhindered upper body movement during rigorous maneuvers. The hip plates must fit snugly to prevent shifting of your body from side to side. Padding hip plates and knee braces is usually done with minicel foam for excellent custom fit. If you plan to learn rolling (and I highly recommend it) a snug fit in the cockpit is very important so that you can hold yourself in the kayak while it is upside down. Needless to say, you will not be able to do anything without sturdy and unbreakable footbraces.

Many novice paddlers, being apprehensive of 'tippy' kayaks, tend to select short and wider craft wanting a very stable and predictable platform to learn on. In reality, once they are in this boat, there is nothing to learn and they soon realize that little additional performance can be squeezed out of such kayak. Think of a child practicing on a small bicycle with 'outboard' training wheels. As soon as balance is established and the fear of falling off is over, the support wheels become a hindrance. A bicycle or kayak like this becomes a real drag and is quickly retired to the back of a garage not to be used again.


High performance, seaworthy kayaks (like the Cape Ann Storm or the Expedition), on the other hand, will feel a bit 'tender' (lower primary stability) on flat water but this tendency becomes an asset in larger chop and random wave patterns because the kayak is not rocked and thrown around by pitching waves passing under the hull from all directions. Flat bottomed or wide (beamy) kayaks that behave so well on smooth water become as unpredictable in waves as the wave pattern they are in. Since the wide flat bottom 'wants' to sit flat even on the slanted face of the wave, the paddler must continuously fight and lean to regain upright attitude. A moment of inattention can turn into a swimming lesson very quickly. Kayaks that are very stable on flat water are said to have high 'primary stability'.





The more tender feel of a seaworthy kayak in completely flat water is not a flaw but an intentional and necessary design compromise to improve handling in waves. Rounder, elliptical, and 'flared' V shaped sections do not force the hull to stay flat on the face of a wave. This promotes your sense of stability and in fact (perhaps, counterintuitively), when the kayak is cradled in waves the ride is very comfortable. When leaned into the wave, the flared side of the kayak (and its associated volume) offers buoyancy and support. Such a kayak is said to have lower primary stability but good secondary stability.
It is important to realize that the effect of the 'flare' on secondary stability is not confined only to the mid section of the kayak ( as illustrated here with the red witness lines) but along the entire length of the hull.



Being a large paddler myself, secondary stability is an important design feature in my sea kayaks not only from a perspective of seaworthiness but essential to paddling enjoyment for people with a larger, heavier build.

Another important performance indicator is the 'waterline beam' or BWL . By default, most kayaks are described only by the overall length LOA and beam or BOA. BOA shows only the maximum width of the kayak which says little about its performance or stability. For example, let's say you have two kayaks, one 21"BOA and the other 22.5". Now, the 'wider' 22.5" kayak can have a narrower waterline than the 21 incher, and all things being equal, it will be faster and show higher secondary stability but not necessarily primary stability. This just shows that assumptions based on this measurement alone can give you totally wrong impression about a kayak.



As far as hull shape is concerned, a full waterplane and higher volume stern and bow sections are yet another design feature I felt was very important to incorporate into the kayaks in order to qualify them as 'seaworthy'.
Waterplane refers to the shape of the hull where it intersects the surface of the water (at ANY draft of depth!). Its shape affects the volume at the ends of the kayak and thus contributes to stability, buoyancy, performance in waves as well as safety. You may have noticed that many kayak designs have a distinctly slender or 'pinched' ends (top kayak in the picture below) with the middle of the kayak 'bulging' out. This may give the design a certain aesthetic appeal but it contributes nothing to its seaworthiness.



As a wave passes under the kayak, under some conditions, the middle of the hull is 'out of the water' and the stability and buoyancy of the kayak literally hinges on the bow and stern sections which are now sitting in the peaks of the wave (picture below). Submerged low volume tips do not provide buoyancy or stability and the kayak will feel tippy and unwieldy. Full waterplane shifts the internal hull and deck volume toward the tips which enables the bow and stern to ride over the waves rather than slicing through them.



This issue also goes beyond stability and the inconvenience of a bucket of heavy sea water landing in your lap. Buoyant bow with a rocker (curvature of the keel at the bow) reduces the tendency of a kayak to 'broach' in following seas. This means that when you paddle with the waves coming at you from your back, and when the wavelength of the waves is about 1 to 1.5 times the length of the kayak waterline(LWL), the bow buries itself in the wave trough (while the stern is over the peak and out of the water) pivoting the kayak sideways and flipping it.





The Double, Storm, and the Expedition have full waterplane and high volume ends for that reason. The volume associated with full waterplane has otherwise no influence on speed because it is largely 'out of the water'.

High performance cruising and touring kayaks on the open sea also require a long waterline for speed, good directional stability as well as paddling comfort. The shorter the kayak, the more it yaws (turns left and right) with every paddle stroke. A lot of paddling energy can be wasted on course correction alone not to mention the frustration when this goes on and on. A longer kayak is said to have a larger Longitudinal Inertia (Il) or resistance to this motion.
A long hull has also a larger submerged 'lateral plane'. This gives it a bigger bite in the water to resist turning while the kayak is upright. Leaning the kayak on its side, changes the shape and size of the plane which allows the paddler to turn and maneuver.
The same goes for pitching (rocking back and forth) in waves. A kayak with longer waterline and waterplane passes over shorter waves without being caught in them and 'rocking' with them. The long distance between the paddler and the tips of the kayak creates an effective arm (lever and moment) to lift the bow out of the water with less effort, giving you a much drier ride in waves than in a shorter kayak.

If you plan to tour with camping gear, do some fast paddling, or cruise mostly along the coast of the open sea or lakes, a long hull is simply more comfortable and efficient to paddle. When I go paddling myself, I often realize that a kayak that looks so long in the workshop is not so long after all, once you put it in the perspective of a vast and energetic Ocean environment.

Paddling in a seaworthy kayak on the open Sea is an indescribable experience. This is especially true if it's in a craft that you built with your own hands.
No matter what kayak type or brand you choose, whether ruddered or rudderless, never underestimate the power of the sea and venture out in conditions that you have any doubt about and cannot handle.


This page just barely touches on the aspects of sea kayak performance but I hope that these pointers help to make a bit of sense of some of the very important issues of seaworthy kayak design and usability and make your choice of the right sea kayak clearer. If you have more questions about One Ocean Kayak designs feel free to contact me.



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Vaclav Stejskal
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Last page update: 29 October 2013