Facts about the Sea Kayak

Sea kayak history & origins

Author: Frederik Laursen & co-author Andreas Holm, November 2020

The kayak was invented and developed by the Inuit, the Eskimo people of the Arctic region who migrated to Greenland via northernmost Canada, Alaska and Russia.
The kayak has been used and developed for at least 4,500 years, perhaps much longer, and was intended for transportation and as a hunting tool to exploit resources when killing seals, walrus and smaller whales.
The kayaks were built according to the “skin-on-frame” principle, i.e. a frame built from available materials such as driftwood and whale bones lashed together with leather straps from bearded seals and finally covered with sealskin.
Such a kayak was hollow, without bulkheads and would not sink if filled with water.
To seal the kayak over the cockpit hole, the hunter wore a tuilik, a kind of hooded anorak that fitted tightly to the hunter’s face and wrists and whose lower part fitted over the cockpit so that water could not fill up the kayak.
The captor was rowing with a wooden oar, which was extremely durable and effective in waves and water with ice floes.
From childhood, he had learned to roll the kayak around as a form of self-rescue in case of an accident.
If you fall out of the kayak, the water in the Arctic regions is too cold to get back in and out of the kayak and you’re basically finished!
The Inuit learned many different ways to roll the kayak around, for example, they could also get back on an even keel if, after harpooning a marine mammal, they were dragged away and wrapped in harpoon lines.
The original Greenlandic kayak and these many rolling techniques are still practiced in Greenland, where Greenlandic rolling is practiced as a sport, which is also a discipline taught in many kayak clubs around the world.
For example, every year there is a rolling championship where competitors are challenged to roll the kayak in 34 different ways.

Today, skin-on-frame kayaks are still made, partly in the old-fashioned way, but often covered with canvas instead of sealskin.
There are also modern skin-on-frame kayaks made from aluminum frames covered in nylon, Kevlar and polyurethane.

However, modern kayaks are often produced in one piece, either in composite materials, i.e. glass, carbon or Kevlar fibers, as well as various plastics.

Structure of the sea kayak

A modern sea kayak made of plastic or composite materials is often somewhere between 4.5 to 5.5 meters long and about 52-64 cm in width.
This is where you need to read carefully if you’re looking for a sea kayak for the first time!
“You can’t have everything in a kayak”!
You have to decide for what purpose you want to use the kayak.
Kayaks are made for racing, polo, surfing and rafting.
Sea kayaks are made for short and medium trips and expeditions.
Kayaks are made for technique, play and Greenlandic roll.
Some of these kayaks are a bit more all-round, but basically, the hull shape of the kayak is designed for specific purposes.
Then there’s the choice of material and whether to choose a plastic or composite kayak?
I’ll try to elaborate on that below.

Kayak hull shape and design

The hull design is crucial for things like kayak stability and speed, which are two opposing characteristics.
A short and wide kayak will be stable but slow, whereas a long and narrow kayak will be faster and somewhat more unstable, especially for the untrained kayaker.
The hull bottom design also has a crucial impact on the kayak’s stability and speed through the water.
A flat-bottomed kayak will be the most stable but somewhat slow, whereas a round-bottomed and/or V-shaped bottom provides a better glide through the water, basically because flat bottoms have a larger area in contact with the water and the latter two have less contact surface and thus less friction.
So you have to decide whether you want a stable and somewhat slower kayak or a less stable but faster kayak.
It almost goes without saying that a beginner will go with the more stable kayak and, with more practice, move on to a narrower and longer kayak.

Rudder or Skeg?

We also talk about hull “leap” and “waterline”.
A kayak with a lot of leap is more banana-shaped and has less waterline as more of the kayak’s bow and stern protrude above the water.
Such a kayak swings around more efficiently and is suitable for technique and play.
A kayak with more waterline has a straighter hull and such a kayak is far more directionally stable, glides through the water faster and is most suitable for long trips and expeditions.
The hull design is a compromise between different characteristics.
The different variables such as: length, width, leap, waterline and bottom shape are “tweaked”.

Kayak equipment

A modern sea kayak is also characterized by having a watertight bulkhead (wall) in front of the feet and one or perhaps two watertight bulkheads behind the seat so that the kayak has two or three watertight cargo holds for stowing gear, but also for the kayak to be unsinkable, unlike the traditional Greenlandic kayak.
The sea kayak is also equipped with a cockpit hole, either round, oval or keyhole-shaped with a rim that can hold the spraydeck or skirt.
A small round cockpit is often a little tricky to get in and out of and requires some practice.
On the other hand, the small round cockpit gives a feeling of being more at one with the kayak and is often a choice for the experienced kayaker.
The large semi-oval cockpit is often a good choice if you’re a beginner, or if you have challenges with hips or knees.
This cockpit hole makes it very easy to get in and out of the kayak even in difficult conditions in waves and surf.
The keyhole cockpit is a middle ground that on the one hand gives the feeling of being more at one with the kayak, but at the same time makes it a bit easier to get in and out smoothly, but only with one thigh at a time.

Deck lines are found on the deck of the kayak, which are important for securing gear and/or for towing or rescues.
In addition, there are also often rubber bands mounted on the front and rear decks for holding gear.

The cockpit is often fitted with a more or less comfortable seat, thigh supports and footrests.
Many sea kayaks are also equipped with a rudder mounted on the stern of the kayak, which is controlled by footrests with integrated foot pedals.
In addition, many sea kayaks also have a fin, also called a skeg, which can be lowered into the water for better directional stability.
If you’re a beginner, a rudder for steering the kayak is comfortable.
As you become more experienced, many rowers prefer to steer the kayak by edging the hull to one side, causing the kayak to steer to the opposite side.
Some kayaks, for example.
Some kayaks, such as the original Greenland kayak, have neither rudder nor fin and if you ask experienced kayakers, it will often be “religion” whether to choose one or the other or maybe both.

Plastic or composite?

In principle, there is no difference between plastic and composite materials in terms of speed.
It’s the weight and stiffness of the kayak that comes into play, as well as the price of the kayak!

Composite kayaks are often significantly more expensive than plastic kayaks.
The most expensive plastic kayaks cost around 14-15,000 DKK, while composite kayaks easily exceed 20,000 DKK for fiberglass and over 30,000 DKK for carbon and Kevlar kayaks.

Today, however, plastic materials are so good that renowned and reputable kayak manufacturers produce 3-layer rotational molded sea kayaks that match composite kayaks in strength, rigidity and weight.
In many cases, plastic kayaks are actually far more robust when encountering rocks and shells on the shore, where composite kayaks are significantly more fragile.

Most plastic kayaks today are rotationally molded in large molds that are heated and then PE (Polyethylene) plastic granules of HDPE (High Density PE) and LDPE (Low Density PE) are injected.
The rotation distributes the granules around the mold and when the mold cools down, the plastic solidifies and a new layer can be injected.

A 1-layer kayak has a thicker wall thickness to maintain the rigidity of the hull and this often affects the weight, which is why 1-layer kayaks are often the heaviest, but probably also the most robust, as they have to face many rocks and shells before the hull wears through.
They are also the cheapest kayaks on the market.
But beware!
There are some very cheap kayaks on the market of extremely poor quality, as they are easily deformed if stored incorrectly, e.g. on trestles or brackets clamped to a wall.

3-layer kayaks are often lighter and more rigid in the hull.
The inner and outer layers often have a completely smooth finish.
The middle “sandwich layer” is a porous but very stiff yet lightweight plastic material, which aims to stiffen the hull but also make the kayak lighter than 1-layer kayaks.

Composite kayaks (composite: two materials) are made of fibers such as fiberglass, carbon and/or kevlar in combination.
Fiber mats are mounted in a kayak mold and glued together with e.g.
polyester or epoxy, which stiffen the entire hull.
The mold in which the kayak is cast can be painted with gelcoat so that the color follows when the hull is released from the mold.
The hull can also be carefully machined and painted afterwards to achieve the desired finish.
Composite kayaks are often more expensive due to the more laborious manufacturing process.
Some believe that composite kayaks have a much nicer finish, but on the other hand, they are also much more fragile and rarely stand up to being hit by rocks and shells on the beach.

The development of technology has also made it possible to create completely new kayaks with built-in benefits that were not possible before.
As we like to say: “You can’t have everything in one kayak”.
Nevertheless, we have succeeded in producing, for example, modular kayaks, or folding kayaks, which have advantages such as being easy to stow away and easy to transport.
For insights into different folding kayaks, see the DIVEIN review HERE.”

If you are a beginner and have never tried sea kayaking before, watch this video: https://www.youtube.com/watch?v=LuG2ynsr6_A

Hope the above will help you choose the right kayak that meets your needs and that you have many unforgettable experiences on the water!
The adventure is right out there on the sea around Denmark 🙂