How a kayak is made and the materials used in making it determines its performance, durability, appearance, weight, price, and even what kind of experience you’ll get from paddling it.
Rotomolded kayaks and thermoformed kayaks are two popular kayak construction options in the market. But to a kayaking beginner or non-manufacturing expert, they’re just big-sounding words that don’t really tell you anything.
Is there a difference between these types of kayak materials? Is one better than the other? What are the advantages and disadvantages of each option?
Knowing the answer to these questions will enable you to choose the kayak material that’s right for you. In this article, I’m going to break down the unique features, strengths, and weaknesses of both a rotomolded kayak and thermoformed kayak.
In the end, you’ll be fully informed and ready to go shopping for the kayak that’s best suited to your needs and preferences.
Photo by Quang Nguyen Vinh
What is a Rotomolded Kayak?
Photo by Rachel Claire
Rotomolded kayaks also referred to as plastic kayaks or polyethylene kayaks have been around since the 1970s. They are a kind of hardshell kayak that is made using the rotational molding process.
This manufacturing process involves pouring polyethylene powder into a hollow metal mold and then heating and rotating it in a high-temperature oven until the entire mold is coated in the melted plastic.
Rotomolding allows manufacturers to create both the kayak deck and hull in one swoop rather than producing them separately before welding them together. Once the molten plastic cools down, the mold is taken off, leaving behind a perfectly formed single-piece kayak.
The manufacturer only needs to add a few finishing touches like smoothing the edges, affixing a rudder or skeg, and fitting the cockpit and storage hatches, and the kayak will be ready to use.
What is a Thermoformed kayak?
Photo by Howard Herdi
Thermoformed kayaks get their name from the thermoforming process which is used to manufacture them. Unlike rotomolded kayaks that are formed inside a mold, thermoformed kayaks are created over a mold.
The thermoforming process uses ABS plastic sheet material with a thin top layer of acrylic which is bound to a frame to hold it in place. The frame is then heated in an oven at temperatures of 350° to 400, essentially turning the sheet into a rubber-like texture.
Once the sheet of plastic has been sufficiently heated, it is placed over the mold until the heat seals the plastic against the mold’s edges. At this stage, vacuum pressure is applied to the mold to pull the heated plastic further down and allow every detail in the mold to be imprinted on it.
The plastic is then left to cool, leaving behind a kayak part. Unlike rotomolding which produces the whole kayak at once, thermoforming allows the kayak to be manufactured in two parts.
The female mold is used to produce the kayak deck and the structure of the mold dictates the surface quality of the kayak. On the other hand, the male mold is used to form the bottom or hull of the kayak and determine the material thickness of the hull’s base.
Once the deck and hull parts of the kayak have been thermoformed, they are trimmed and joined with adhesive and tape. Then they’re detailed, rigged with the necessary kayak components and accessories, and offered for sale.
Rotomolded Kayak vs Thermoformed Kayak – Structural strength
Which kayak is stronger and less likely to be damaged by impact, thermoformed or rotomolded kayak?
Photo by Rok Romih
Rotomolded Kayak
In terms of impact resistance, no other type of kayak can deliver the level of performance you’ll get from a rotomolded kayak.
The hardshell nature of polyethylene combined with the rotomolding process used to shape the materials makes it almost indestructible.
With a rotomolded kayak, you don’t have to be picky about your kayaking destinations. You can explore any kind of water you want, be it rocky rivers, shallow lakes, or even whitewater rapids.
The kayak will take pretty much anything you throw at it without breaking, cracking, or puncturing.
Thermoformed Kayak
Since thermoformed kayaks are also made of plastic, they have incredibly hard exteriors and are stiff enough to resist impact without damaging the structural integrity of the boat.
There’s not much difference between thermoformed kayaks and rotomolded ones on the strength front. However, thermoformed models are more resistant to scratches and abrasions than their counterparts thanks to their acrylic-covered outer layer.
This acrylic covering is also responsible for the glossy, eye-catching finish that thermoformed kayaks are beloved for.
Thermoformed Kayak vs Rotomolded Kayak – Weight
The weight of the kayak you buy can make or break your paddling experience and affect how the boat handles in water. Let’s see how a rotomolded kayak and thermoformed kayak perform on this front.
Photo by Frank Cone
Thermoformed Kayak
Thermoformed kayaks use fewer materials in the manufacturing process than their rotomolded cousins, which ultimately results in a kayak that feels lightweight.
Although ABS plastic might not be the lightest kayak construction material you can get, they are definitely lighter than polyethylene.
A thermoformed kayak is perfect for people who want the strength and resistance of a rotomolded kayak without the heavy weight.
Rotomolded Kayak
Unfortunately, rotomolded polyethylene kayaks are not lightweight in nature. In fact, they’re the heaviest kayak material on the market.
You’re probably not going to be able to load, unload, and transport your kayak on your own if you’re a person of average strength. So unless you always plan to go paddling with company, you’ll want to keep the difficulty of moving the kayak around in mind when making your final decision.
Rotomolded Kayak vs Thermoformed Kayak – Versatility and Durability
Are there limits to the type of environment you can explore with a rotomolded or thermoformed kayak? How much use can you expect to get out of both before it’ll become necessary to upgrade to a new kayak?
Photo by Katie Cerami
Rotomolded Kayak
Rotomolded polyethylene kayaks are built to withstand all kinds of abuse including rocky shorelines and cobblestone beaches. They also do great in depthless lakes, violent rapids, and coastal waters littered with tree branches and other obstacles.
Regardless of where you plan to take a float trip, you’ll be covered as long as you’re using a rotomolded kayak. Also, you can easily strap it to your kayak roof rack without worrying too much about it getting damaged during transportation.
The sturdy nature of rotomolded polyethylene makes it a popular kayak material for beginners in the market for sea and touring kayaks with great stability. However, more experienced paddlers can also find rotomolded kayaks designed for their skill level.
Another factor that makes rotomolded kayaks a crowd favorite is their durability. Even with zero to minimal care, your kayak will serve you well for many long years before it succumbs to wear and tear.
Thermoformed Kayak
Thermoformed kayaks are wildly versatile watercraft that can go from one use to another without breaking a sweat.
Whatever purpose you want your kayak to serve whether it’s kayak fishing, recreational paddling, or embarking on multi-day touring expeditions, you’ll find a premium thermoformed kayak that satisfies your needs.
The acrylic outer layer of thermoformed vessels helps to protect the kayak from the harmful, weakening effects of the sun. So you can spend as much time as you want outside without having to first apply UV protection to your kayak.
Although a thermoformed kayak won’t last as long as a rotomolded model, you can still enjoy many years of paddling if you take reasonable care of the watercraft. And when the time comes for you to discard your thermoform kayak, you can recycle it because the plastic it is made from is typically recyclable.
Thermoformed Kayak vs Rotomolded Kayak – Storage, Care, and Repairs
Which kayak is easiest to maintain and restore in case of damage?
Photo by Oliver King
Thermoformed Kayak
Although thermoform kayaks are highly resistant to sun, abrasions, and scratches, they might also crack or break if they experience considerable or high-pressure impact.
The good news is that any damage sustained by your thermoform kayaks can be easily repaired with the right materials and equipment.
To extend longevity, thermoformed kayaks require some degree of care. You’ll need to store the kayak upside down in a cool, dry place and clean the interior and exterior with soap and water from time to time.
Rotomolded Kayak
With a rotomolded kayak, you can get away with pretty much forgetting that your boat exists until you want to take it out. However, it’s advisable to still take some basic precautions to care for the kayak and increase the years of use you get out of it.
For starters, the kayak should be stored outdoors in a shaded area or indoors in a cool and dry place, away from windows and heat sources. This will help minimize sun exposure which weakens the plastic and makes it prone to cracks.
Every now and then, use mild soap and water to clean your kayak’s insides and outsides including accessories. Always let your kayak dry thoroughly before storing it away.
Finally, use plastic protectants to protect your boat from UV rays and restore its shine when the color starts looking dull.
Rotomolded Kayak vs Thermoformed Kayak – Price
How expensive are thermoformed kayaks compared to rotomolded kayaks?
Photo by Reijo Telaranta
Rotomolded Kayak
The process of manufacturing a rotomolded kayak is simpler and faster than processes used in making other types of kayaks. As a result, polyethylene kayaks cost less than boats made with other kinds of materials.
So if you’re looking for a reasonably priced hardshell kayak, going for a rotomolded kayak will help you stay within budget.
Thermoformed Kayak
Thermoformed kayaks also don’t require manufacturers to devote huge swaths of time to the process of making them. They are slightly more expensive than kayaks made from rotomolded polyethylene, but they won’t burn a hole in your pocket either.
Pros and Cons
As with most things, rotomolded kayaks and thermoformed kayaks have their allure and drawbacks that may inspire you to purchase or give you pause.
Knowing the advantages and disadvantages of both types of kayaks can help you decide which one is better for your needs and preferences.
Pros of Rotomolded Kayaks
- Extremely versatile.
- Affordable and commonly available.
- Highly resistant to impact and unlikely to get damaged even in rough waters.
- Unparalleled durability even without regular maintenance.
Photo by Gaspar Zaldo
Cons of Rotomolded Kayaks
- The kayak’s hull can weaken or warp if it’s strapped to a roof too tightly on a hot day.
- Cuts and scratches from rocks and other abrasive surfaces can cause fuzz to appear on the plastic, resulting in reduced hull speed and increased drag.
- UV rays from the sun cause polyethylene to deteriorate, so you have to treat your kayak with UV-blocking wax or spray to help it last longer.
- Rotomolded kayaks are heavier than other types of kayaks, making them more challenging to carry or transport, and difficult to control in the water.
Pros of Thermoformed Kayaks
- The acrylic outer layer gives it a shiny, luxurious finish that makes it look less like plastic and more like a composite kayak.
- Increased resistance to scratches and abrasions.
- Repairs can be carried out pretty easily.
- The materials used in manufacturing them are recyclable.
- Thermoformed kayaks are lighter than rotomolded kayaks.
Photo by Matthias Groeneveld
Cons of Thermoformed Kayaks
- They’re not widely available so you might not be able to find the particular design you want in this material.
- The ABS layers will degrade and weaken over time irrespective of how well you maintain the kayak.
- If you take the kayak out on the water at below-freezing temperatures and it suffers very hard impacts, your thermoformed kayak might shatter.
Final Verdict
The best kayak material is ultimately a matter of preference. The choice between a rotomolded kayak and a thermoformed kayak will come down to how you intend to use the boat, your storage and transportation options, and even your budget.
If after considering the merits and downsides of both kayaks you’re still unsure of which to buy, I recommend going with a rotomolded kayak. It’s cheaper, stronger, more durable, extremely low maintenance, and well-suited for every type of water and environment.
