How can I minimize the chances for cold cracks?
Royalex is susceptible to shrinkage when exposed to freezing temperatures. A sheering fracture (cold cracking) is a potential hazard if you live in area with rapid fluctuation or freezing temperatures, particularly canoes with wooden gunwales.
To avoid this hazard, consistent application of Gunwale Guard oil finish will minimize chances of cold cracking. Cold cracking is not covered under the canoe’s warranty. Cold cracks, should they occur, are repairable by contacting your local dealer. Synthetic Gunwales are less prone to cold cracking, but covering your canoe with an insulator such as a moving blanket can help lessen the chance if a severe drop in temperatures occurs.
If I store my boat outdoors, do I need to worry about UV damage?
Not if the vinyl skin is intact. Over time there will occur some color fading but this can be prevented by periodic treatments of a UV protectant such as 303, available from Harmony. The application of a UV protectant will create a slippery surface for a limited period of time.
One of the reasons we like 303 is that its water based and makes for a less slick surface. Nonetheless, when/if you treat the interior of you boat be cautious when you next use it to avoid slipping and losing your balance.
It temperature a threat to Royalex canoes?
Yes and no. Very extreme heat can deform the canoe but the temperatures must be very high and very sustained. This is usually not a problem unless the canoe has been placed in a clear polyethylene sleeve or bag and left out in the sun. This can deform the canoe permanently but most people don't keep their canoes in a plastic bag. The problem occurs more often when new boats are delivered to a shop or customer and left outside in their packaging materials.
Royalex® is much more resistant to heat deformation than canoes made of polyethylene. Cold temperatures can pose a bigger threat. Royalex® canoes can be susceptible to cold cracks due to hull contraction and expansion. Wooden railed canoes are more prone to this than those with synthetic gunwales. Most canoe manufacturers have taken steps to minimize the possibility of cold cracks and include tips on how to store your boat for the winter season in their owner's manuals. More information on cold cracks and repair can be found below.
Isn't Royalex indestructible? Why would it need a repair?
ABS Royalex® is an incredibly durable material but it is not indestructible. Back when Royalex® started to show up in canoes, it was nothing short of a revolutionary advance in canoe materials. Its functional durability put it in a class by itself compared to other available technologies of the time such as aluminum or fiberglass or wood.
Canoe manufacturers could be forgiven if they got a little too carried away with this almost magical material. Images of canoes sailing off factory roofs or falling from airplanes and surviving contributed to the growth of Royalex®'s reputation for being "indestructible."
Is repairing Royalex difficult?
Not particularly. Royalex® repair often consists of restoring damage caused by an accumulation of wear and tear and this type of repair is not difficult or complex. It does get more challenging if you're intent on repairing a boat that has been wrapped or severely distorted to the point where the hull has torn. The difficult part is not the actual repair of the hull material but in restoring the original hull shape. In situations like this, you are usually also facing replacement of the gunwales or rails as the hull can be distorted far more severely without permanent damage than can these structural members.
Repair of dents and deep scratches involves filling with Royalex® repair resin. Repair resin is a puttylike 2-part resin that cures to a hard finish. Some sanding will be required as well. Repairing tears or cracks requires multiple layers of Kevlar® cloth laid in and covered by the repair resin. Fiberglass cloth can also be used but the inherent flexibility of Kevlar® better matches that of Royalex®. Structural repair is generally done on the interior of the hull.
The ends of my canoe are worn to the point where the outer layer is gone and I'm seeing some of the same problem at spots along the keel line. What should I do?
The outer (and inner) layers of a Royalex® hull is vinyl. There're there to provide UV protection for the underlying ABS plastic layers that in turn surround the foam core. The ABS layers are quite susceptible to UV degradation. The vinyl layers block that potential damage. Over time and considerable use, it is not unusual for that vinyl layer to be worn away. As the vinyl wears, you'll start to see a new color appearing. The vast majority of Royalex® material has been made with the ABS layers of a differing color than the vinyl skin. This makes it easy to gauge the wear on the vinyl layer.
While the canoe is still structurally intact, it is wise to restore that layer of UV protection to your hull. If the ABS has not been too deeply scratched or gouged a simple, albeit temporary, solution is to simply paint over the exposed layers. Most canoe manufacturer's provide color matched ABS Touchup paint You can expect to have to paint again in the future as the paint is abraded away. A more permanent option to consider if the wear is concentrated at the ends of the boat and the underlying layers are in good shape is to install a skid plate kit.
This will not only protect your hull's integrity but will add strength to the hull. If the ABS layers have been scraped or gouged you may need to consider filling with Harmony Royalex® Repair Resin and then painting over the new material. Repair resin is a thick paste that spreads easily and cures to an extremely hard finish. If properly installed, it is unlikely to require additional repair in the future.
I've got some dents and creases on the outside of my hull. Do I need to repair these?
Probably not, especially if the outer skin is not cut or missing. Flip your boat over and look inside the hull. If you don't see a corresponding crease on the inner hull surface most likely the damage is cosmetic. Structurally, the hull is fine unless you see that corresponding crease. This indicates the damage extended first into the foam core, compressing it, and then through the inner ABS layers.
If the boat is used primarily in milder waters, you can probably live with this damage if not too long or large in scope. If you're paddling demanding whitewater or going to remote locations it'd be prudent to repair it as this depression can become a "hinge" in event of an "incident." Some shallow dents can be repaired by heating the area with heat gun. This can re-expand the foam core. If necessary, structural repair would consist of reinforcing the damaged area with a matrix of repair resin and glass cloth applied to the inside of the hull.
What is a cold crack?
Paddlers living in colder regions or in areas subject to rapid temperature fluctuations have learned that Royalex® canoes can be subject to what are called cold cracks. Cold cracks occurred when temperatures reached the teens or lower and/or there was a rapid temperature swing of 20-30 degrees in a few hours. Royalex® is an elastic material and will shrink or expand slightly due to temperature changes.
At colder temps, the material has a tendency to contract. When that contraction occurs at a different rate than that experienced by the gunwales, the hull could crack at the screws or rivets used to attach the gunwales. These cracks would often extend up to 8-10" down into the hull of the canoe. Contrary to most damage incurred by paddling, cold cracks can be identified by their vertical orientation. In severe cases, one could encounter a series of 6 to 8 or more cracks originating at a succession of attachment points. Royalex® canoes with wooden gunwales were somewhat more susceptible to this problem than those with synthetic rails. As canoe manufacturers became aware of this problem, they took steps to reduce its occurrence.
Steps recommended for the user to take included backing out the screws in the ends of the boat as cold cracks tended to occur more frequently in these areas. Steps were also taken in the production of the boats to make this problem less likely and these precautions have appeared to have had an impact as incidents of cold cracks have diminished. Still, its possible to experience the problem or to find a canoe for sale with the problem. Indeed, if you are fortunate to find such a boat, you will often find a bargain as the damage looks worse than it is.
As cold cracks are found up near the gunwale, they're located in a less critical area than if they were found below the waterline. Repair consists of removing the gunwale, aligning the hull parts and reinforcing the interior hull with Royalex® repair resin and cloth. Cosmetic repair of the hull exterior is accomplished by slightly widening the crack and filling with repair resin.
I've punched a hole in my boat. Can it be repaired?
Unless it's big the hole can be fixed pretty easily by taping a piece of cardboard with a piece of wax paper or plastic wrap on the outside of the hull and then building up the gap with layers of fiberglass cloth and Royalex® resin.
Can I get a deformed canoe back into shape?
You may need to build a "jig" to reshape the canoe to its original form. This can be done with duct tape, cardboard, and wood as well as any other materials that come to mind if they'll do the trick. Be creative. If the damage is confined to one side of the boat, you can force out (or in) the damaged side by bracing temporary cross-members off the sound side of the boat. Run a line of rope or cord down the center of the boat from end to end and sight down the line to assist in making the boat as symmetrical side to side as possible. Gettinag the two sides of the crack to align can be trickier.
Any bracing or jig should be applied to the hull exterior since you'll be doing the repair primarily on the inside of the hull. Taping lengths of cardboard or thin bendable wood strips will often help the hull take its original "fair" curves or close to it. It can be challenging to conform the crack should it extend through the chines (where hull side transitions to bottom). Again, be creative. You can force a hull "out" by running a down brace from a thwart or yoke ending with a plywood or foam pad against the hull. If a thwart or yoke is not in proper position, make a temporary cross member and wedge it under the gunwale to anchor your down brace.
If you're faced with bringing in part of the hull to conform, it's a bit more challenging. It may sound counterproductive but you can drill two small holes close to the crack and run a line through them and up around a thwart or yoke and tension the line to conform the hull. In most cases the drilled holes will ultimately be covered by repair material so no further damage has really been done.
I installed some whitewater outfitting in my boat, and later noticed that the hull is kind of spongy under the knee pads. What's up?
Probably what's happened is due to the adhesive or the amount of adhesive you used. Contact cement in particular emits styrene as it cures and if too much adhesive was used or the adhesive wasn't allowed to "flash off" before the outfitting was installed, the styrene will migrate into the hull where it can soften the ABS layers and break down the foam. The result is a soft wrinkled area in the hull.
This should be repaired as it is a weak point and can be the starting point for more excessive damage. Repair will involve removing the softened material and replacing it with successive layers of fiberglass cloth and repair resin. This is an entirely avoidable type of damage. Proper selection and use of your adhesive will prevent its occurrence.
Contact cement is commonly used as its simple to use, inexpensive, and it works. Use as little adhesive as possible, just enough to "skin" or cover the two surfaces to be bonded. Most adhesive damage comes from using excessive adhesive.