Question on lifetime of rotomolded polyethylene boats

The typical rotomolded polyethylene boats from name-brand manufacturers (as opposed to discount/box store stuff), what is the typical lifetime for –

  1. A boat always stored out of sunlight?

  2. A boat that may be stored in sunlight a fair amount of the time?

  1. Longer than yours.
  2. Same answer if UV protected.

Plastic kayaks from reputable brands come with UV stabilizers in the plastic, such that a boat would have to have years of cumulative sun time before it shows sun damage.

If a boat is stored outside in sun, the signs of sun damage you would see would be some fading of colors (and brighter color plastic where sun doesn’t hit, like under straps or inside hatches). This is cosmetic and is not a failure of the boat. What the sun does do that could lead to a failure is that it:

  1. makes the plastic more brittle
  2. makes the plastic less likely to accept plastic welding as a repair.

So the failure would be a hard hit causing the plastic to crack, and the plastic not being repairable. Even the most sun damaged kayak could still work fine, so long as it doesn’t get that hard hit. At the places I guide.teach for, we have lots of Necky kayaks from the 90s which are still going strong, and all live outside with limited sun protection.

But a brand new, non-sun damaged kayak could also be broken with a hard enough hit. Theoretically should take a harder hit than a sun-exposed one, and would be more likely to be repairable with plastic welding than a sun exposed one, but it can still happen. The one kayak I broke was about a year old one that was stored inside which I cracked by the skeg box due to going over a pour over without enough water, and the stern slammed down on the rock (that same pour over has stripped a rudder off another boat I had due to the same thing - too bad it is such a fun pourver, as it is also a costly one). That cracked skeg box boat I sold cheap to a friend who is more handy than I and is still going strong.

The poly boats that I’ve seen stored mostly outdoors are usually not quite the way they were originally shaped. They still might last a long time, but the warped hulls and sagging decks may not be so neat.

depends on how often you drag over shells and rocks
In our area UV is not as significant as in FL or the south
The hulls usually wear through first

Like other commenters wrote, store it out of the sun. My Old Town Cayuga, a single layer poly boat, is 14 years old, my OT Loon, a polylink3 boat is twenty and our Wilderness Zephyr is 12. They’re stored in the garage and once or twice a season we apply Formula 303 to them. All three kayaks still run straight and true and the hulls have held their shapes well. Sun is fun, but it’s a killer to plastic over time.

I should mention is that my agenda is evaluating used kayaks, not how to store a boat I own. The issue is if a kayak is X years old and it was stored in/out of the sun, is it approaching the end of its useful lifespan?

We have two 23 year old Perception Keowees that except for a gazillion scratches are as good as when we bought them. they were always stored under a roof. They are used by us, our kids, and our grandkids
We recently sold a fifteen year old Perception Eclipse and Shadow that were the same

I’ve bought numerous rotomold kayaks over the past 10 years that dated from the mid 1980’s to the mid 90’s, so we are talking boats that were 25 to 30 years old. But all had been taken care of and had no evident fading or UV damage and all were in the Northeast for most of their lives (not exposed to the year round high heat you might find in the Southern states).

Particularly the old Perception and Dagger kayaks seemed to have been made with very strong poly.

As to an absolute age maximum, I think that it’s impossible to generalize because so many factors affect storage and use. I have only ever had one badly aged kayak, a late 1980’s Aquaterra Chinook which had been neglected and stored in a yard in a trailer park for Lord knows how many years. Besides being horribly oil-canned the plastic was dry looking and crazed with tiny cracks. I expect a sharp blow with anything would have cracked that brittle plastic wide open. I only paid $75 for it – only got it because it had a really nice aftermarket stainless steel rudder assembly installed in it. I removed that and gave the boat to a friend who had a small farm pond so her kids could mess around in it. It is probably still languishing in their barn, no doubt with raccoons nesting in it! Never did install the rudder in one of my kayaks – ended up selling it for $80 so the original purchase was a wash (I figure it cost me $5 in gas to go fetch the the kayak from the trailer park.)

@l2t said:
I should mention is that my agenda is evaluating used kayaks, not how to store a boat I own. The issue is if a kayak is X years old and it was stored in/out of the sun, is it approaching the end of its useful lifespan?

About the same as a used car.
A 57 T-Bird from socal probably a long life.
A Yugo from Michigan not so much.

@grayhawk said:

@l2t said:
I should mention is that my agenda is evaluating used kayaks, not how to store a boat I own. The issue is if a kayak is X years old and it was stored in/out of the sun, is it approaching the end of its useful lifespan?

About the same as a used car.
A 57 T-Bird from socal probably a long life.
A Yugo from Michigan not so much.

Hey, I had a Yugo back in the day. Went well for four years, LOL. Would’ve loved an old T-bird.

Boats from the 90s and before may not have deck lines, which you want. Boats from 80s and before may not have bulkheads, which you want. So the real old boats would likely get kicked out just due to some safety considerations.

Newer boats can be more comfortable and have more accessories. The seats from the boats in the last few years are so much nicer than the hard plastic seats common from the 00s and before. And thought has been added to hatches and bungees and such with newer boats. And also to the basic hull designs and such.

Because of these, I likely woudn’t get a boat more than 10 years old. At that young age, plastic condition generally isn’t much concern. The boats I like the most (playful day touring boats) were few and far between even 10 years ago, and the ones made now are so much better than the few available then.

But you can still check to see if the color in spots out of the sun is much different than what is exposed, and that will give you a feel for possible sun damage.

I had a rotomolded Perception Swifty, manufactured in 1999, stored outside in central Florida for 13 years. It had not faded or become misshapen or brittle when it was stolen in 2013.

@l2t said:
I should mention is that my agenda is evaluating used kayaks, not how to store a boat I own. The issue is if a kayak is X years old and it was stored in/out of the sun, is it approaching the end of its useful lifespan?

Maybe
But there is a good chance it has a thicker hull than new boats especially if it is a name brand
And if from the North even better

One exception is the Hobie. To avoid a hull cracking problem they make the hulls out of much softer plastic, which wears faster. The abrasion these hulls suffer in a single season is amazing. Not good!

In my experience it depends on three basic things 1. the thickness of the original plastic 2. How it was stored 3. How it was maintained. A good quality kayak stored properly out of the sun and treated regularly with 303 UV protectant can have an indefinite life span. Even a good quality boat that is not properly cared for will have a much shorter life. Properly cared for a good quality kayak could go 20 or 30 years.

My rotomolded poly Wilderness System SOT is 18 years old. There’s some obvious wear and tear, but I think it’s good for another 10 years if I take care of it. That said, I’m in Southern California, where we don’t get a lot of temperature extremes that would put stress on the hull. I also store it out of the sun. of course.

The one kayak I’ve killed was an Eddyline Sandpiper, which lived on the roof of my car much of the time in the summer (When one goes out 2 - 4 times a week, it gets old taking it on and off!), and became more and more brittle over the years. I held it together with Gorilla tape for a few years, which worked fine, but last season I bought another one, because it got to every time I bounced it over a rock it cracked another spot. But I love that boat - especially the weight, and possibility of putting on and off roof by myself; the handling is great; I’ve had it out in pretty gnarly conditions on big lakes and along the Maine coast and felt confident in the boat. It’s not rotomolded; my Loon (what I take if I know I’ll be bouncing over rocks) oilcans if put on the roof racks with any heat at all. All my boats live under cover on north side of house when not in use.

There must be some variables to sun exposure? I would expect a boat left in the sun in Seattle for three months to survive longer than a boat left out for nine months in the blistering heat of the southern gulf states? Is the issue the sunlight or high temperatures or both? Would a plastic boat suffer more if stored on hot concrete or a rocky beach vs say a soft cooler lawn?

I bet some boats that get parked in the sun is due to owner laziness or lack of awareness. But for some owners leaving their boats in the sun all the time is just a cost of doing business if they live on the water and enjoy paddling with minimal portage and roof rack hassles…

If you want to mitigate the cost of doing business marine wax,303,and a tarp are effective sun blocks. The sun eats a poly tarp a year covering my boats.