How To Fix Oil Canning In Plastic Kayaks (2025 Guide)
I'll never forget the sinking feeling when I spotted those ugly dents in my favorite fishing kayak's hull last spring. After a winter stored on sawhorses in the garage, my trusty Perception had developed the telltale oil canning that makes plastic kayaks look like someone took a hammer to them. The good news? I fixed it myself in about two hours using nothing but Florida sunshine and some patience.
Oil canning in plastic kayaks happens to the best of us. Whether it's from cranking down roof rack straps too tight (guilty) or storing your boat wrong over winter, those annoying hull indentations can pop up when you least expect them. The term comes from the way the dents flex in and out like an old-style oil can - push on them and they might pop back, only to return later.
After fixing dozens of oil-canned kayaks over the years and talking with folks at kayak shops across the country, I've learned what actually works versus what sounds good on internet forums. Here's everything you need to know about fixing and preventing this common problem.
What Exactly Is Oil Canning?
Oil canning shows up as indentations or depressions in your kayak's hull, making it curve inward instead of maintaining that smooth outward shape. You'll usually spot it on the bottom where the kayak sits on roof racks or storage supports.
The plastic gets stressed at pressure points and eventually gives way, creating these annoying dents. While they might not sink your boat, oil canning definitely affects performance - I've noticed my kayaks with bad oil canning track poorly and feel sluggish in the water.
Why Plastic Kayaks Get Oil Canning?
Polyethylene kayaks are particularly susceptible because the material has some flex to it. That flexibility is actually good for durability (plastic bounces off rocks instead of cracking), but it also means the hull can deform under pressure.
The main culprits I've seen:
- Over-tightening roof rack straps (the #1 cause)
- Storing kayaks hull-down on hard surfaces
- Dragging boats across parking lots or launches
- Extreme heat exposure during storage
- Supporting the kayak at the wrong points
Last summer, my buddy left his Wilderness Systems Tarpon strapped to his truck for a week during a heat wave. When we finally went to launch, the hull had oil canned so badly where the straps crossed that it looked like someone stepped on it.
The Heat Method: Your First Line of Defense
The easiest fix uses something most of us have plenty of - sunshine. Here's my go-to method that's worked on everything from my old Dagger to brand new Pelicans:
Sunlight Method
Turn your kayak upside down with the hull facing up. Position it so the oil canned area gets direct sunlight. On a hot day (80°F or warmer), leave it for 2-3 hours. The heat softens the plastic enough that many dents pop out on their own.
I've had the best luck doing this mid-afternoon when the sun's strongest. Sometimes I'll hear a satisfying "pop" as the dent releases. If it doesn't fully pop out after a few hours, apply gentle pressure from inside the hull with your hands while the plastic is warm.
Hair Dryer or Heat Gun Technique
When Mother Nature won't cooperate, break out the hair dryer. This method requires more caution but works year-round:
Hold the hair dryer 10-15 inches from the hull and keep it moving constantly - never let it sit in one spot. Work in a circular pattern over the dented area for 5-10 minutes until the plastic feels warm and pliable.
With heat guns, be extra careful. I learned the hard way that these tools get hot enough to melt plastic if you're not paying attention. Keep it at least 12 inches away and never stop moving it. The plastic should get warm, not hot.
Once heated, push gently from inside the hull to encourage the dent out. Sometimes placing a tennis ball under the dent and pressing down around it helps pop stubborn ones.
Hot Water Treatment
This works great for smaller dents or when you can't use other heat sources. Boil a large pot of water (not quite boiling - around 180°F is perfect). Pour it slowly over the dented area from the inside of the hull.
The weight of the water combined with heat often pushes dents right out. I've used this method on my fishing kayak accessories compartment areas where hair dryers can't reach well.
When Heat Isn't Enough: Advanced Fixes
Sometimes oil canning is too severe for simple heat treatment. Here's what I do for stubborn cases:
Internal Bracing
For persistent dents, I've had success using internal supports while heating. Cut a piece of foam pool noodle or dense foam to fit inside the hull at the dented area. This provides constant outward pressure while you apply heat.
On my Jackson kayak, I used an inflatable camping pillow inside the hull while heating - it worked perfectly to push out a nasty dent from winter storage.
Weight and Pressure Method
After heating the hull, some folks have luck using sandbags or water jugs to apply weight from inside. The key is distributing weight evenly across the dented area, not creating new pressure points.
Preventing Oil Canning: An Ounce of Prevention
After dealing with oil canning multiple times, I've learned prevention beats any repair:
Proper Transport
When loading kayaks on roof racks, use cradles or foam blocks that support the hull properly. Cam straps should be snug but not cranked down tight - if you see the hull flexing, you've gone too far.
I switched to J-cradles that hold my kayaks on their sides, completely eliminating transport-related oil canning. For longer trips, I'll loosen and retighten straps at gas stops to relieve pressure points.
Smart Storage Solutions
Never store plastic kayaks sitting on their hulls long-term. I use padded sawhorses that support the boat at the bulkheads - the strongest points. Wall-mounted racks that hold kayaks on their sides work even better.
During winter, I store my boats indoors if possible. Temperature extremes make plastic more susceptible to deformation. If garage storage isn't an option, at least keep them out of direct sun and support them properly.
Regular Maintenance
Part of my spring kayak maintenance routine includes checking for early signs of oil canning. Catching it early makes fixing much easier.
Know When It's Time for Help
While most oil canning is fixable at home, severe cases might need professional help. If you've got multiple deep dents, cracks forming at stress points, or the hull won't hold its shape after repair attempts, it's time to consult a kayak repair shop.
I once saw a kayak so badly oil canned from improper storage that the hull had essentially collapsed. At that point, replacement made more sense than repair.
Real-World Success Stories
Last month, I helped a neighbor fix her Pelican that developed oil canning from sitting on concrete all winter. Using just afternoon sun and gentle pressure, we had it looking new in about three hours.
Another paddling buddy successfully fixed his Old Town using the hot water method when nothing else worked. The key was patience - it took three treatments over a weekend, but the hull finally popped back.
Materials Matter
Not all plastic kayaks are created equal. I've noticed thermoformed kayaks like Eddylines resist oil canning better than standard rotomolded polyethylene. The denser, stiffer material holds its shape better under pressure.
If you're shopping for a new kayak and worried about oil canning, consider kayak materials carefully. While poly boats are affordable and durable, they're most prone to this issue.
Quick Reference: Oil Canning First Aid
When you spot oil canning:
- Assess the damage - is it one spot or multiple areas?
- Try the sunlight method first on warm days
- Use hair dryer or hot water for targeted heating
- Apply gentle pressure from inside while warm
- Be patient - some dents need multiple treatments
- Consider internal bracing for stubborn dents
FAQ Section
Can oil canning damage my kayak permanently?
Not usually. Most oil canning is cosmetic and fixable with proper heat treatment. However, severe cases with multiple deep dents can affect performance and might indicate the plastic has weakened. I've paddled kayaks with minor oil canning for years without issues.
How hot is too hot when using a heat gun?
Keep plastic surface temperature below 160°F. If the plastic starts looking shiny or glossy, you're too hot. I always keep my hand near the work area - if it's uncomfortable for me, it's too hot for the kayak.
Will oil canning come back after I fix it?
If you don't address the root cause, yes. I fixed oil canning on my first kayak three times before realizing my roof rack setup was the problem. Fix your storage and transport methods, and the repair should be permanent.
Can I prevent oil canning with hull reinforcement?
Some paddlers add internal bracing or foam supports for long-term storage. While this can help, proper storage position and support points matter more than reinforcement.
Does oil canning affect kayak performance?
Yes, especially if severe. Dented hulls create drag and can affect tracking. My fishing kayak with bad oil canning felt noticeably sluggish until I fixed it.
Should I use a torch to heat my kayak?
Never. I've seen melted hulls from overzealous torch use. Stick with controlled heat sources like sun, hair dryers, or hot water.
How long should I wait between heat treatments?
Give the plastic time to cool completely between attempts - usually 2-3 hours. Repeated heating and cooling can weaken the material if done too quickly.
Can I fix oil canning in cold weather?
It's harder but possible. You'll need to work indoors or in a heated garage. The plastic needs to warm up significantly from ambient temperature to become pliable.
Is oil canning covered under warranty?
Rarely. Most manufacturers consider it damage from improper storage or transport. Check your specific warranty, but don't count on coverage.
What's the difference between oil canning and warping?
Oil canning creates specific indentations that can flex in and out. Warping is permanent deformation of the entire hull shape, often from heat exposure or improper storage. Warping is much harder to fix.
The Bottom Line
Oil canning might look alarming, but it's usually more of a cosmetic issue than a structural one. With some heat and patience, you can restore your kayak's hull to its proper shape. The real key is prevention - proper storage and transport will save you from most oil canning headaches.
I've fixed oil canning on everything from budget recreational kayaks to high-end fishing boats. The methods work the same regardless of brand or model. Just remember: heat is your friend, but too much heat is your enemy. Take it slow, be patient, and your kayak will be back to its old self.
Now quit reading and go check your kayak storage setup - your hull will thank you!