Kayaks have several features that we love. The seats, mounts, skirts, cleats, bungees, hatches and pedal drives, among others. But there is one kayak feature that you must prioritize above all these: the hull.
Why is the hull so important?
The hull of a kayak is its foundation, the underpinning principle. As the “skeleton” of a kayak, the hull is usually designed or shaped according to the paddling activities the kayak is intended. For example, a whitewater hull is typically short, curved at the bottom and rounded on its sides. For a sea kayak, the hull is often long, flattened at the bottom and pointed. Usually no two kayak hulls are the same. And even if they appear similar, their designs tend to be quite different.
Which are the most common hull designs?
While there is a wide range of kayak designs, there are generally 4 common groups.
- Rounded hulls
- V-Shaped hulls
- Flat Hulls
- Pontoon hulls (Also called tunnel hulls)
Hulls with rounded edges are used to give boats a torpedo shape and boost boat speed. For kayaks intended for less water resistance, more maneuverability and greater secondary than primary stability, rounded hulls are preferred.
As the name suggests, these hulls have a sharper V-shape intended to increase the hull’s ability to cut through water and enable the boat to track more effectively in straight lines. Kayaks with V-shaped hulls are generally very fast and occasionally tip because they have greater secondary than primary stability.
When kayaks are to designed to offer both greater stability and better maneuverability, flat hulls are used. Kayaks with flat hulls offer more primary than secondary stability and are ideal for a wide range of purposes, including as fishing boats and play boats.
Pontoon hulls boast incredible stability because they combine the primary stability of flat hulls and the secondary stability of rounded ones. However, while pontoon hulls offer great stability and decent tracking, they don’t offer good speed.
What’s meant by the terms chine and rocker?
Kayaks aren’t just different in terms of hulls. They often differ in the way they curve or don’t curve, either at the bottom or on the sides, which are called rocker and chine respectively.
When the kayak’s bottom curves and meets its sides, determining how rounded or boxy a kayak is, this is called chine. There are two types of chine: soft chine and hard chine. A more rounded meeting between the bottom and sides of a kayak is soft chine, while a more angular meeting is hard chine.
When a kayak has a harder chine, it will track better, offer greater primary stability and provide a flatter surface to push up against in choppy waters. This makes boats with harder chines more prone to capsizing in bad weather. Harder chine hulls are ideal for play boats because they offer sharp edges that catch waves better and ensure tricks are easier to perform. But kayaks with softer chine hulls have greater secondary stability and better speed.
It’s important to know that hard and soft chines are just the extremes. In fact, there are numerous multi-chine hulls that lie somewhere between the two ends.
The curvature of a hull from its bow to the stern is called rocker. A kayak with more rocker swings from the bow (front) to the stern (back), ensuring greater maneuverability as the stern and bow experience less resistance when the boat is in water. But boats with more rocker track less effectively compared to those with less rocker. In fact, a flat-bottomed kayak,which means it has no rocker, tracks best because its stern and bow experience the most resistance in water which prevents it from turning. As with chine, a kayak can be designed with any degree of rocker and may even have rocker only on the bow and not on its stern or vice versa.
What’s the difference between primary and secondary stability?
Primary stability is the initial steadiness of a a boat when on flat water, while secondary stability is the ability of a boat to remain stable when it is tipped on its side. During kayak design, a careful balance between primary and secondary stability has to be made depending on where the kayak is to be used. For instance, a kayak tailored for coastal fishing comes with the primary stability necessary to fish, but also must have adequate secondary stability to handle choppy waters. That is also why a kayak that’s very stable in flat water will feel tippy in rough water and vice versa.
Kayak design takes into consideration several factors, including design symmetry, hull materials, water entry line, weight positioning and more specific features such as keel lines or sponsons. By understanding the basics of hull shapes and how each shape is appropriate for specific purposes, you are better prepared to know which type of kayak will best suit your needs and paddling goals.
Looking for a great boat for your next adventure? At Captain Mike’s, we have a wide assortment of sit-on-top and sit-in kayaks for experts and beginners, tandem paddlers and single paddlers. Our boats are stored in an enclosed space, carefully cleaned after each use and are in great shape. We offer them at a great price too. For more information on our range of kayak styles, prices and rental policies, visit the “Captain Mike’s Kayak Academy” site.
- Austin Kayak. (2012). A Look At Kayak Hull Designs. Retrieved from https://www.austinkayak.com/blog/2012/08/a-look-at-kayak-hull-designs/