Anyone ever see a deformed plastic boat?

I keep on hearing not to tighten down too much when putting my rotomolded kayaks on the roof rack. Don’t leave them on their sides, don’t do this, don’t do that…

A friend has 2 kayaks that are 4+ years old and he does all the above, and they are not deformed. He drives long trips with them cranked on with ratcheting tie downs, and they are perfectly shaped.

So, has anyone ever seen a deformed kayak from such treatment?


plastic boats
I’ve owned a number of rotomolded boats beginning in the early 1980’s. Yes they have deformed. Yes, they have returned to their original shape. There is also a big difference between rotomolded and blowmolded boats. They look very similar but blowmolded boats are much stiffer (at least the ones I have compared).

Hot weather
doesn’t help. Mine doesn’t deform when its cool.

I don’t mean temporarily becoming more pliable in heat- I mean permanently deforming from being tied down tightly or something. To the point where it won’t track or has a lump in the hull or something like that…

I’ve seen quite a few cranked down and bent up pretty badly.

I have

– Last Updated: May-18-07 10:46 PM EST –

Quite a few, actually. One friend in particular has a Looksha with two permanent dents in the bottom each of which is about *four inches* deep. No kidding. The boat's owner straps it down tightly in the summer and leaves it on the car much of the time. Those dents are not coming out on their own.

I have two fiften year old ones that have permanent indents on the underside from where they were on the saddles.

They are not so pronunced that they affect the paddling, but never the less they are there.

If you are a casual paddler and they are not cinched down for long periods of time I don’t think it will happen, but these boats were on the vehicle roof more than they were off of it.

On that “ratchet” thing: that is the worst thing you can do. Cinch them down tight by hand, but don’t ratchet them down.



One of my older boats is a Wilderness Systems RM. I started cartopping it upside-down because the saddles were pushing into the hull a couple of inches. (the deck is much stiffer than the hull)

I saw someone car topping a RM kayak on the freeway last summer- their front tie down was cranked so tight the boat was bent down about 30° over the front saddles.

No plastic
Deforming is why I dont have plastic boats anymore. We had one that would deform if you looked at it hard. I have seen them severely deformed on several occasions. It gets tied on to the rack, it loosens up and gets cinched tighter, repeat this process a few times and see what happens.

My old CD Storm
My old CD Storm gets a big depression on the bottom if it is strapped down tight on a trip. After I get home I can pop it out with hot water, and on my vehicle I avoid strapping it in that weak area. It also seems to want to edge turn rightward, so it must not be arrow straight anymore either.

I would try
I would try hot water on those dents.

“plastic boat”

Sure,the best example is the original Perception Sea Lion. There’s a HUGE range of sizes, types, composition, shape under the category “platic boats”

Some will never deform, some will always deform. Depends on the boat and temperature.

Use cam straps not ratchet tie downs.

Move to Tucson and you will see amazing things. My neighbors boat looked like the melting wicked witch of the west in his garage.

Here in San Diego I’ve seen several boats on Craigslist listed for sale that have deformed hulls.

Yes. I bought a Necky Looksha Sport
at an Olympic fund raising auction, and had to improvise a way to carry it home on my Yakima racka. Unfortunately, my “solution” caused the keel to pooch upward forward of the seat. I was able, with some difficulty, to get the hull to return to the original shape.

If you forcefully distort a poly hull past a certain point, the plastic will begin to stretch, and lose its “memory.”

I am sure that if I could see what the friend of the original poster has been doing to his boats, I would be able to understand why his boats are not deformed. However, it is trivially easy to deform poly boats, and no one who values the original form of his poly boat should treat this issue lightly.

I will suggest that
The boat’s owner isn’t too hard-core about speed and distance, but maybe she’d want to try improving the boat a bit. Hot water sounds like a good idea.

I have two like that. Cam straps was
enough pressure to cause the indents. As they get older the material will thin-out enough for them to pop back out.

Yes, oilcanning
I have an older plastic boat that was tied down too tightly a few too many times. It does not appear “deformed” when it is out of the water, but the softened area near where it was tied down pops in when it is on the water. I imagine this effects hull speed to some extent.

Actually, we saw the same orange RM boat a few times coming back from our vacation in Maine a couple of years ago. They stopped at the same rest stop on I-95 that we did, and we alternately passed each other a couple of times. Our best guess was that the boat was ruined. It was a plastic boat of moderate length - probably 14 or so feet - on top of a sedan so there was a pretty short run of roof and a lot of overhang.

The boat was torqud down so tight via the bow line, also the stern but less so, that it truly bent downward from the roof. This could not have been easy to do by the way - I forget which but it was made by one of the companies that has really tough plastic. We didn’t see any way that this uone could be corrected by letting it sit in the sun and pop out - it was too deformed.

Not unlikely that this was the first time these folks had tried taking this boat over such a long distance, probably was the first time of this boat going to Maine. So they may not have had any practice at getting the boat set for this kind of trip.

It was a hot day - I would wager that if it’d been a day of coastal storms it wouldn’t have bent so badly. But the way this was tightened down, I’m not sure that it would have escaped damage even with that.