C-Forum

How does oil canning affect the performance of plastic hulls? It seems that kayak hulls are getting thinner and thinner as manufacturers use seat rails and pillars to stiffen up newer designs. The result is that my conversions of late seem to have more of a tendency to oil can. Is this something to be concerned about? Do plastic OC hulls oil can as well or does the saddle help prevent it?

Many of my boats have had oilcanning - two ancient Slashers (worse when I pulled the wall out to squash the stern), Score, Rockit, etc. I have always blamed oilcanning for my inability to do aerial donkey kong mcFlip twists. Other than that, I can't say I've noticed any actual problems asides from aesthetics.

My Remix shows no signs of oilcanning because I used the J "Not Elvis" etc Plate (tm) system - I can't aerial donkey kong mcFlip twist that boat because it weighs so daggum much (and so do I...). MY SF doesn't have any signs of it, but it has the Smerda approved 12 cubic feet of foam bulkhead style outfitting.

performance issue....

link about stiffness - from a racing shell company:

I doubt its a noticeable issue for normal use, other than being a bit unsightly.

Smurfwarrior wrote:I doubt its a noticeable issue for normal use, other than being a bit unsightly.

guess not...

... if you don't mind giving up some of your speed and handling, such as
when attaining, or going for that wave, or keeping up with the rest of the pack

Oil canning and other hull mutations other than being unsightly also change the performance of the hull. A minor one is they change the volume of the boat, probably not in a significant way, but in some for the new spud playboats who knows. What is changes the most has to be how they affect hull speed, by changing the smooth plane to and undulating washboard your going to lose speed. I have a Pyranha burn that has a pregnancy (opposite of oil can) and the stern has a tendancy to bog down much more when paddling flat water, so I have to assume it does this when I have trying to make a move across current in in a big drop.

The oil canning or pregnancy will also become a weak point in the boat as well. All of my more serious class V buddies will replace a boat for a more intact one when the hull becomes oil canned and the only reason I haven't replaced mine is because I'm cheap. Now if your just a casual boater it might not be a big deal, but if you want to get the most out of your hull, it's best to have it fully intact.

sbroam wrote:I can't aerial donkey kong mcFlip twist that boat because it weighs so daggum much (and so do I...).

You just need a bigger feature

I don't have two boats w/ the same design to compare. That said, I have a plastic Big EZ & a 'glass Sith. There is a noticeable difference (beyond the design differences) in the feel of the hulls on a wave. The Sith is very stiff & feels like it's alive on a wave. The Big EZ has a lot of flex in the hull that I can feel while surfing.

If the hull material is not stiff enough to maintain the shape, that deformation will prevent the hull from performing as designed. Unless, like a flat-bed trailer the hull is designed to flex INTO the desired shape when under load.

In my business, the only thing worse than oil-canning is a bad piece of ash.

Mike W. wrote: If the hull material is not stiff enough to maintain the shape, that deformation will prevent the hull from performing as designed. Unless, like a flat-bed trailer the hull is designed to flex INTO the desired shape when under load.

Or like prestressed concrete. I don't need to lose weight, I just need a prestressed boat!

Can we avoid oil-canning by "Red Canning"


(opens door for Smerda)

Thanks everyone. Jeff, that's what I thought. It really doesn't matter that much.

cheajack wrote:Thanks everyone. Jeff, that's what I thought. It really doesn't matter that much.

Obviously you didn't read all the replies, Jack. It sure seems to matter to some people.

Uh, well.. my personal experiences with paddling buttboats 'pre oilcan' and 'post oilcan' reflects on my original statement where it doesn't really matter that much. THAT MUCH meaning it isn't going to be super noticable. I'm not talking a composite race boat in a race situation where you want to get everything out of the hull and I don't think racing was the original concern of the OP. Of course there is some difference in how the boat reacts to the water with oilcanning but I think some people like to over analize things for whatever reason. Maybe its cold out and they arn't boating.

all oil canning means to me is that my hull is tired and going to crack soon.
my experience anyways.

Thanks Larry. My Karnali cracked and oil canned at the same time. The crack (7") was between the seat rail and my knee and the seat rail bent inward/upward just in front of the saddle and that is where it is oil canned. I have welded the crack and glued a piece of old hull to the bottom, but it is still slightly oil canned until I strap in. Getting into the outfitting seems to flatten out the bottom. Your answer is the one I was looking for. I was wrestling with the dilemma of trying to get all the oil canning out of this boat or start outfitting it's replacement. I'm pretty cheap and have enjoyed the Karnali, but have a Fluid Solo sitting in my office getting converted five minutes at a time.
I now carry strips of Pella window and door flashing tape in my dry box for emergency repairs.
I actually think the Karnali hull stretched when it broke and that is why it remains oil canned. Is this a far fetched notion?