Thermoformed kayaks in cold water

Thermoformed kayaks become brittle in very cold water and can crack if you hit an object (this happened to me once). My question is, exactly how cold is “very cold” water? Any thermoformed owners who paddle in water around 40 degrees? What has been your experience? I wonder, for example, about stepping into the kayak, putting full body weight on the bottom (floating, not on land). Anyone paddle a thermoformed kayak in the winter?

Which brand thermoform cracked on you? I read that Hurricane hulls are thinner than either Delta or Eddyline.

The crack was my own error.

Hi Waterbird,

There’s a property of materials called the Glass Transition Temperature…it’s the temperature below which the material loses flexibility. If you know the material a boat is made of you can look up the Glass Transition Temperature. A thermoformed boat could be made from different types of plastics…or a material that sounds the same but might differ in performance because of additives. Google says that most thermoformed kayaks are made of polyethylene and the glass transition temperature for polyethylene is below -100F so you’d never have a brittleness problem in cold weather. I’ll also mention that the glass transition temperature is a range…so if you had a boat that was brittle in 32 degree water it’s still going to be brittle at 40F.

Seems like your boat should be fine unless the manufacturer chose a poor plastic for the application. If you know the material of the boat you cracked and also the material of the boat you’re worried about we may be able to draw conclusions. You could also contact the manufacturer and ask for the glass transition temperature if the material they use since you’re wondering about cold weather usage.


Eddylines are made with ABS and acrylic plastics, not polyethylene. I believe Delta and Hurricane use similar materials (rotomolded kayaks are polyethylene). I seem to recall that these materials do get brittle at cold temps but of course I can’t find that info now.

It is also air temp that you need to worry about.

Eddyline and Delta do use a form of ABS plastic. Standard ABS has the following description and temp rating (they may use a non-standard variant, so actual rating may be different).

ABS (Acrylonitrile Butadiene Styrene) is an amorphous thermoplastic material, with a continuous use temperature range of -4° F (-20° C) to 176° F (80° C). It is categorized as a standard material, and offers a balanced combination of mechanical toughness, impact resistance, and ease of fabrication and thermoforming.


I don’t believe I’ve seen or heard of a thermoformed hull of PE, either high or low density. As others have said ABS is the norm, but it’s certainly possible that some manufacturers have tried (or are trying) other polymers.
Still, when I paddle cold water - which is increasingly rare these days - I use my RM Old Town Camden, partly because the 3-layer PE doesn’t seem to get brittle but mostly because it is nearly impossible to dump.

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Pelican thermoforms their boats out of PE (combination of new and recyled). The note from earlier where someone said “most” thermoformed boats are PE would technically be correct, as Pelican’s output in terms of units is many degrees larger than Eddyline or Delta, even though they’re not a brand most of us think of that way.

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Interesting, I should have known that as I had a Pelican pedal boat made of their Ram-X (high molecular weight cross-linked PE) some years ago for visiting kids.
Very durable and very good resistance to UV oxidation/fading; it was the only boat I ever left outside (other than an old Grumman canoe). Of course, as with other PE hulls, there’s a weight disadvantage. The Pelican Argo 10 and Eddyline Sky 10 look to be comparable, but the Pelican weighs 25% more (40# vs 32#). On the other hand, being heavier may be a non-issue if it’s left outside and dragged to the water anyway (as was my pedal boat).

Full disclosure, we’re retailers for both brands, but they’re not comparable boats on the water. Sky 10 is an honest 32 lbs and relatively stiff, with sharp lines. Argo is a bit heavier, but also significantly softer both in the lines and in the materials.

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Sorry, in no way did I mean the two were comparable in performance.

Except that this is known to be false. There are quite a few reports of thermoformed kayaks cracking in cold weather/cold water, and I have experienced it myself. It’s a known drawback of thermoformed kayaks, necessitating special care.

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I’m only interested in water temperature here. Air and water temperature are not always directly related, especially in late fall and early spring. In the northern U.S. the air could be 70 degrees on an unusual day in December, giving an illusion that the kayak is safe, but the water temperature could be 40 degrees. Therefore it’s important to understand the limitations of the material.

The composition of the materials used in thermoformed kayaks is a closely guarded secret. I’ve asked companies this question many times and have never gotten an answer. I’ve heard (unconfirmed!) that the material all comes from the same factory, but it is made up to the specifications of each retailer as to composition and thickness. Thickness is another big secret. This secrecy is too bad because it makes it hard to compare the properties of different brands and choose the safest material for one’s specific use. I paddle until there is ice on the lakes, so I need to know what I’m paddling. Sort of like you really want to know the properties of your vehicle tires in rain, snow, and ice. There are plenty of people testing tires, but not kayaks. Maybe it’s time for the industry to address this information gap about their materials, given the huge increase in the number of paddlers.

Thank you, this is useful information in a general sense, since the exact temperatures would vary according to the other additives.

Well I guess water can’t go below 28°F .

ABS is used in many car parts also.

I bet most manufacturers employees don’t know specs or don’t want to tell if they do know.

Correct. But I’ve also put the question directly to two company presidents and got an evasive answer. I hope it doesn’t take a fatality some day to clear this up.

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I saw two Hurricanes destroyed from being split wide open by water freezing in the open cockpit.

That and a few other major breaks that shouldn’t have happened based on the situation (wouldn’t have happened to a rotomolded or any decent composite kayak) turned me off of the thermoformed kayaks.


Yes I missed that thermoformed boats are generally made of ABS not polyethylene. I think I may have misinterpreted the relevance of glass transition temperature too. Sorry!

Today I just happened to trip over an article in Paddling magazine called “What are kayaks made of?” and they list Pro’s and Con’s for all materials and for Thermoformed one Con is “Be cautious in cold climate. In below-freezing temperatures hard impacts can shatter thermoformed laminate.”