Mohawk Shaman canoe cracking in bow and stern

[Sir Adam]

Mohawk Shaman canoe cracking in bow and stern
by Willy Willy

My Shaman has been developing small one to two inch cracks in the bow and stern and one in front of the seat. It was built in 1999 but I bought it new Christmas 2001. Mohawk suggested that I put West System epoxy and fiberglass on the areas to patch it. I did that. The stern continued to show more cracks. I put a piece of fiberglass larger than my hand over the cracks last time. One of the smaller cracks had already cracked into the foam. Last weekend on the Lower Yough I went over a small one foot ledge and heard a loud crack. I checked the outside of the hull and it looked okay. Later when I let air out of the airbags I could see that I now had a crack about nine inches long running from the stern curve towards the bow. It is all the way down into the foam. It cracked all the way through the fiberglass patch and the inner Royalex layer. Has anybody ever seen a new Royalex canoe do this? What are your thoughts?

Willy

Posted on Aug 14, 2002, 6:22 PM

storage?
by Rob W

You haven't been storing it in the sun have you? UV can degrade the abs plastic and make it brittle. It certainly seems a bit early for such severe damage otherwise. I bought a probe 12 in '99 and other than some vinyl rubbed off of the bow and stern stems it still seems solid but I've been paddling c1 almost exclusively the past two years and the mohawk hasn't left the garage too much. They aren't making royalex sheets like they used to. I've seen much older canoes than mine with less wear than mine quite often. I heard that they changed the process for rolyalex some years ago because the chemicals they were using were so toxic. Just what I heard, don't know for sure if it's true. good luck.

Rob Weum

Posted on Aug 15, 2002, 5:08 AM


It is only 6 months old and usually stored in the shade
by Willy Young Willy Young

The dealer I bought it off of had kept it in his building out of the sun. It just looks like bad royalex to me.

Posted on Aug 24, 2002, 9:00 AM

Royalex
by Daniel Holzman Daniel Holzman

This sounds like a serious problem with the Royalex itself. Royalex is a tradename for a sandwich construction material which consists of an inner core of foam ABS plastic (ABS is acrilonitrile butyl styrene, a common plastic), with an outer layer of sheet ABS, covered by a thin layer of PVC (polyvinyl chloride), which acts a screen for ultraviolet radiation, which definitely degrades ABS.

If you scratch off the PVC, you will see the ABS sheet material underneath, which is generally black. If you scratch through the sheet material, you will see the foam, which is often yellowish. ABS has been made for a long time, I have a 20 year old ABS boat which has seen hard use, yet the ABS is still in excellent condition. I also have a 14 year old ABS canoe which has seen extremely hard whitewater use, and the plastic has softened. Neither of these boats has ever cracked in the manner you describe. I have bashed rocks, and the effect is to locally crush the ABS. In order to patch it, I usually heat the affected area (usually the bow) with boiling water, bang the boat back into shape using a dead blow hammer, and patch over the damage if it is serious using fiberglass.

You should not be getting cracks in a relatively new boat, hades you shouldn't get them in an old boat either. I think you need to contact the manufacturer, maybe they had a bad run of plastic, and they might even make good on the boat.

Posted on Aug 15, 2002, 9:45 AM

I have contacted Mohawk
by Willy Young Willy Young

They suggested I continue to paddle it until GAF. They will be up there and look at the boat then. Hopefully they will agree that it is a bad sheet of royalex and do something about it.

Posted on Aug 24, 2002, 8:58 AM


Re: Mohawk Shaman canoe cracking in bow and stern
by Gerry

Are the cracks at the gunwale attachments? If your gunwales are wood there is a difference in expansion/contraction between the wood and the royalex hull and in cold weather which is sufficient to cause the cracks in the hull.
I have cracks in my royalex tripping canoe and have repaired it by stop drilling the ends (drill the end of crack with a small drill ie. 1/8 inch diameter) of the cracks to prevent further crack progression and reinforcing the bow/stern with fiberglass on the inside of the hull.
Ensure that the gunwale fasteners, especially, at the stern/bow are removed and loosen the others for storage in the winter to prevent cracking.

Posted on Aug 16, 2002, 3:50 PM

Cracks are on the inside of boat at the bottom
by Willy Young Willy Young

It has cracked in the bow and stern on the inside where the bottom starts to curve up to form the bow and stern. Several of the cracks are in random directions. The outside looks fine, only showing normal wear and tear.

Posted on Aug 24, 2002, 8:55 AM