While most people today know what a kayak is and what they look like, they are not aware of their many different design aspects. However, the fact is that when a kayak designer sits down to design a kayak hull, there are many different factors that they must consider because changing any one of those factors affects all of the other design aspects of the hull.
Consequently, when the sport of sea kayaking first became popular among modern paddlers, kayak designers based their kayak designs on ancient Aleut and Inuit kayak designs because these indigenous peoples had perfected their skin-on-frame kayak designs over thousands of years of trial and error.
Today, all modern kayak designs can be divided into one of two different categories based on ancient Aleut, Tlingit, and Inuit kayaks and they can be immediately recognized by noting whether they have soft or hard chines.
What is a Chine?
For those of you who are not familiar with the term “chine”…
A chine is the part of a kayak’s hull where it makes the transition from the bottom to the side.
Thus, a kayak with “soft” chines has a soft, gentle, curve at the point where the bottom of the hull transitions to the side as is seen on Aleut, Tlingit, and eastern Inuit kayaks whereas, a kayak with “hard” chines has a sharp, distinct, angle at the point where the bottom of the hull transitions to the side as is seen on some western Inuit and Greenland kayaks.
Initial vs. Secondary Stability
But, before we explore the issue of soft chines versus hard chines, we first need to discuss the concepts of initial and secondary stability.
Thus, initial stability is a measure how stable a kayak is when a paddler is sitting upright in the cockpit on calm water whereas, secondary stability is a measure of how stable a kayak is when paddled in rough seas.
In other words, initial stability is a measure of how resistant a kayak is to being capsized by the paddler while, secondary stability is a measure of how resistant a kayak is to being capsized by a wave.
Soft Chines vs. Hard Chines Kayaks
As mentioned above, a soft-chined kayak is one that has a smooth, rounded, transition between the bottom and the side of the hull whereas, a hard-chined kayak is one that has a sharp angle at the juncture of the bottom and the side of the hull.
Consequently, because soft-chined kayaks have a rounded transition between the bottom and the side of the hull, they tend to have a higher degree of initial stability than kayaks with hard chines do.
On the other hand, due to the fact that hard-chined kayaks have a distinct angle at the juncture between the bottom and the side of the hull, they tend to have a higher degree of secondary stability than kayaks with soft chines do.
How Soft Chines Work
When a soft chined kayak is sitting upright in the water, the pressure applied by the water is distributed evenly around the kayak’s hull. Thus, a soft-chined kayak feels relatively stable when sitting upright.
But, when a soft-chined kayak is leaned onto its side, the rounded transition between the bottom and side of the hull causes the water pressure to build more gradually than the sharp transition between the shallow V bottom and the flat side of a hard chined kayak.
Therefore, due to their rounded transition between the hull and the side, soft-chines have less secondary stability than hard-chines do and thus, a soft-chined kayak is more prone to capsize when leaned on its side than a hard-chined kayak is. Plus, sweeps and edged turns are more difficult when paddling a soft-chined kayak because it is more difficult for a paddler to balance the kayak on its side.
How Hard Chines Work
Hard-chined kayaks on the other hand are notorious for having a low degree of initial stability due to their combination of a shallow V hull and nearly vertical sides.
Thus, when a hard chined kayak is sitting upright in the water, unlike soft-chined kayaks which distribute water pressure evenly around their hull, the shallow V hull and nearly vertical sides of a hard-chined kayak causes most of the water pressure to be distributed along the bottom of the hull with very little of it distributed along the sides.
But, when a hard-chined kayak is leaned onto its side, the nearly vertical side presents a much steeper angle than the rounded side of a soft-chined kayak and thus, water pressure builds much more rapidly against the side of hard-chined kayak. Therefore, a hard-chined kayak feels far more stable when leaned on its side than a soft-chined kayak does.
Consequently, because hard-chined kayaks have less initial stability but more secondary stability than a soft-chined kayak does, hard-chined kayaks are less prone to capsizing when they are leaned on their edge. Therefore, sweeps and edged turns are less difficult when paddling a hard-chined kayak because it is easier for a paddler to balance their kayak on its side.
Soft or Hard Chines? Other Factors To Consider
So, as you can see, the choice of soft chines or hard chines drastically affects a kayak’s initial and secondary stability which, in turn, drastically affects its performance in both calm and rough seas. However, in addition to their differences in initial and secondary stability, both types of kayaks have other advantages and disadvantages as well.
For instance, while it is true that hard-chined kayaks have a higher degree of secondary stability than soft-chined kayaks do, the fact is that most paddlers find hard-chined kayaks to be less stable in rough seas than soft-chined kayaks because of the shape of the hull.
With a soft-chined kayak, when a wave rises underneath it, the wave has a rounded surface to push against and thus, the energy the wave produces tends to be easily redirected around the hull. But, when a wave rises beneath a hard-chined kayak, it has a flat, shallow V, hull to push against which causes hard-chined kayaks to roll more than soft-chined kayaks.
But, if the paddler is experienced, the increased secondary stability provided by a hard-chined kayak also makes easier to remain upright by leaning the kayak into the wave. Thus, some highly experienced paddlers actually prefer hard-chined kayaks when paddling in rough seas.
Furthermore, a hard-chined kayak hull of a given size and shape will have a greater surface area than a soft-chined kayak hull of the same shape and size. Therefore, hard-chined kayaks are also somewhat slower than soft-chined kayaks.
Which is Better?
So, is a soft-chined kayak better than a hard-chined kayak or, vice versa? Well, the answer to that question is neither and both at the same time. In fact, due to their differences in stability and speed, most experienced kayakers find that they have a distinct preference for one type of kayak over the other.
However, it should also be noted that there are far more soft-chined kayaks on the market today than there are hard-chined kayaks and that the majority of experienced paddlers prefer either soft-chined kayaks or so called “British-form kayaks” which combine the characteristics of both.
But, those paddlers who prefer hard-chined kayaks do so for a reason and thus, the answer to the question of whether a soft-chined kayak is better or worse than a hard-chined kayak comes down to personal preference.