Kevlar Malecite Oil Canning

Two years ago, I rescued an early 90’s Mad River Kevlar Malecite. The owner had stored it under a deck for several years, so it had a lovely powdery oxidized blue/brown deck stain color scheme created when he did not move it before refinishing the deck. Additionally, the gel coat was badly crazed. I did a restoration and have enjoyed the boat greatly.

Last year, I was paddling tandem with my sweetheart and we slide over an unseen portion of submerged log. There was no cracking sound, just a “bhump” noise and the bottom began to oil can. I slid amidships, placed both hands on the bottom and gave a bit of a bounce. The bottom went “bhump” again and popped back into place and we paddle without further incident for the rest of the day and the rest of the season.

Today, I had an opportunity to paddle and used a different vehicle for transport. As there were a set of kayak shallow v style foam blocks already installed on the car and we were driving less than 10 miles, we just transported the boat upright in the blocks. The v was not a perfect fit, but the foam thick and fairly compressible. As a result, I put a little more pressure on the tie-down straps than I might have otherwise, but heard no complaints from the boat.

Once on the water, we noticed that the boat was significantly oil canning again. We paddled a bit, but became concerned. The performance was obviously much impaired. Back at the put-in, as soon as my sweetheart stepped out the bow, the bottom popped back into shape. I slid to a kneeling admidships position and the boat stayed in shape. I took it for a test spin with no problems. Thinking we might have again “fixed” the problem, she got back in and the boat began to oil can again.

Does anyone have any experience with this sort of problem? I see no obvious cracks or delamination, and the keel line remains true, without dents and in the correct v shape. Suggestions on repair? I suppose I could add an interior coat of epoxy resin, or even another Kevlar layer on the interior to stiffen things up, but I would hate to add the weight. There are no thwarts in this boat, just a center seat, which may be a replacement. I am also not in love with the way the bow seat is fitted, ending well inside the walls on each side, and providing little stability. Might this be having some effect? I’d love some input.

on many
stock boats and somerace boats the user will install a

brace from the ceter thwart. If you have a center seat try wedging those foam kayak saddles under the center seat.

It seems Malecites did not come with
any thwarts other than the center yoke and two end seats for tandem.

You say there is a center seat. I wonder if it is a replacement seat that is just a tad longer than the yoke it replaced. You might just try shortening the seat a little and then replacing or making a test thwart an inch or so shorter than what is there already.

When you put two people in a tandem that is just a little wider than intended by the designer or inadequately supported all the force is on the end and there is nothing to hold the middle from spreading the gunwales and hence the bottom comes up and flops up and down if its not stiffened.

You can also try wedging in a block of something as suggested…unfortunately a la Coleman.

Hopefully we will hear from some Malecite owners.

Not all
Some Malecites came with a center seat (just aft of amidships) instead of a center thwart.

An outside possibility
is that the previous owner fairly often pulled the boat over logs or things that forced the hull to oilcan. If so, then repeated working of the layup in certain areas could cause it to become weaker and more flexy. This occurs through micro cracking of the resin in the laminate.

Another possibility is that, due to the manner of storage, moisture got into the micro cracks and caused hydrolysis. Before you did your restorative work, did you see small upward-protruding blisters on the gelcoat, in addition to the microcracks? I had a Mad River Compatriot that developed hydrolysis blisters.

I don’t think rolling epoxy over the interior will stiffen anything. You could epoxy Kevlar over the interior, and perhaps it would stiffen the hull without adding much weight. Kevlar is light.

My preferred solution would be to put a solo kneeling pedestal made of minicell between the center thwart and the bottom. That would be functional for paddling and would probably keep oil canning from getting started.

Without seeing it
Here’s my guess: The matrix has been damaged due to over flexing. The flexible Kevlar has held up but the matrix (resin kevlar layers/bond) has been compromised. Kevlar doesn’t like to stick to resin unless chemically coated previous to layup. That’s not likely in this industry, so with impact and flexing the matrix experiences interlaminar breakdown, micro cracking, etc, which will make it spongy.

It CAN be fixed but forget Kevlar. It’s NOT stiff material and adding a layer with some resin won’t do much. Plain old e-glass would be better. To create stiffness I’d suggest a core material such as laminar soric, and cover it with glass. You could use strips of soric or a full panel. Easy to work and can be used wet-layup in this case. Be sure to wet out all the hex channels. Repaired this way you’ll have a hull you can stand on.

Kevlar is strong in tension, not compression and this is an excellent example of it doing it’s job, albeit with other issues. Same matrix in glass “may” have cracked, but glass or carbon bond much better to the resin so a well built glass matrix can likewise take great impact.

Hope this helps. I’d consult a reputable composite outfit to coach you or do the fix for you. Other core options exist, but some sort of core is what you need here.

Good luck.