Can someone give me the “low down” on the difference between the two other than weight?
$$$ vs. $$$$$$$$$$$$$$
Whenever I’ve been asked why various boats are made of different materials, it tends to become a somewhat technical discussion. “Bouncability” may be a newly-created word, but it quickly conveys one of the primary benefits of Royalex. Thanks, Eric.
Royalex is slicker
Royalex and polyethylene are very slick and they slide right over rocks. Also both kinds of plastic boats can be wrapped around a boulder and survive. My boat merely needed a few days in the summer sun to straighten itself. These are the two advantages of these kind of boats.
They are much heavier with poly being super heavy and royalex being merely very heavy.
Poly and royalex will not last as long in the sun as a kelar boat will. I’d guess that kevlar is good for 20 years in the florida sun with little waxing or maintenance, where poly and royalex are good for less than half of that. On the other hand I have a poly boat that is stored in the shade and it is over 15 years old and doing fine.
You’d understand the difference
the first time you paddled through a rock garden. A Royalex canoe would slip right through while a kevlar/fiberglass would scrape through. With low water levels and lots of rocks, I’d take my Royalex, but otherwise I’ll take my kevlar. My eighteen foot kevlar, large displacement tripping canoe weights less than my 14 ft solo Royalex canoe. I load my 18 ft kevlar canoe on my RAM 3500 truck myself, but I doubt I could load an 18 ft plastic canoe without help.
Kevlar- The strongest fiberglass made. Its what bullet-proof vest are made from. It helps to have a good resin with it, that is almost as key if NOT more so than the glass itself. I think ONLY one company makes kevlar and thats dupont…i could be wrong… You can have strong kevlar and not-so strong depending on the amount. Just like the difference between an army tank and a cadillac car…made of steel and metal but different thickness. ALL canoe/kayak manufacturers in North AMeirca and maybe the world use only 2-3 layers of kevlar in ALL there boats, with the exception of ONE company which used 12 layers of kevlar!!! This this company offers boats like a tank! Get it?
kevlar is popular…its easy to fix/repair and work with…Its strong but not bombproof.
Royalex… Oh mixed feelings on that product lately…they have changed quality and company that makes it has gone thru major management changes…they are concerned for the $$$ than the product like they use to be… when they started out it was made by paddlers, now the company is made up of corprate egos…so the product has gone down hill. ONE COMPANY makes royalex for ALL boat manufatureers.
Its strong, durable, easy to fix too. You can smash head-on into boulders and be fine…i do all the time. You can take a sledge hammer to the hull and be ok…same with the 12 layer canoe companies boats out of kevlar.
RX shrinks in cold weather…ie alaska, montana, so you have to be cautious if you have WOODEN GUNNELS but NOT plastic…the wood doesnt shrink like the RX thus it can crack and pull the screws out…get it? No biggy, if you loosen the gunnels in the fall. HOWEVER MAd River willl NOT HONOR THERE WARRENTY EVeN IF YOU DOOOOOOOOO LOOSEN GUNNELS and even tho they say they WILL honor …they DONT, BEEN THERE DONE THAT!!! so be aware of false warrenties with them…
I doesnt take away from me not having a canoe made of each craft…I have both…they are great…
RX is heavier…no big deal
Kevlar is light…no big deal
Kevlar is expensive or more so than RX
The ABS plastic boats are great too like the old town discovery…as a marketing ploy (and a very good one) they drop them from helicoptors and have them fold up when they hit the earth only to be hammered back in place to its original form…
80% of people use them in remote canadian expeditions because you can just pound them back into place instead of trying to patch an rx or kevlar boat…
But Frank, how many “Kevlar” boats
are actually Kevlar on the outside?? Most have E-glass or S-glass on the outside, and will slide over rocks just fine.
Bouncability, Excellent Word
Looks like you’ve summed it up very well with that one word. Everyone’s pretty much summed it up nicely. Don’t think I can add a thing except say “Thanks” to ericnyre for a term I’ll use in the future when I explain the differences myself. WW
(Except Kevlar is not a “fiberglass.”)
You meant to say the strongest composite fabric made, which is true depending on the application. One kind of Kevlar is great for police vests but poor for making boats. Another is good for boats, airframes, etc., but not for stopping bullets.
Then we get into the meaning of “strong.” Kevlar is very resistant to tearing when in a resin layup, but not all that stiff. Carbon fibers make for a very stiff layup that can support a lot of distorting force, more than an equivalent weight of Kevlar cloth… but when the limit of a carbon layup is exceeded, it breaks, while Kevlar can hold the layup together. S-glass makes for a stiffer layup than Kevlar, and S-glass is more tear and split resistant at the limit than carbon, while also exceeding carbon in wear resistance, and slipping over rocks better than Kevlar.
A good source of info is johnrsweet.com. There are now pretty many manufacturers of “generic” Kevlar, called Aramid. Incidentally, Kevlar is a cousin of Nylon, another DuPont fiber. Does anyone know if Dupont claims exclusive use of the name “nylon”? Or did they just quit trying to control it?
Any wimmen wear Kevlar panty hose?
Part of the reason is, a well-designed
composite boat, Kevlar or not, is rather stiffer than an ABS boat. So, even if the surface of a composite boat is something slippery like the carbon cloth on the outside of a Blackgold Bell, rock surfaces are more able to dig into the resin and cloth. If a manufacturer makes the questionable decision to use pure Kevlar cloth on the outside of a layup, then the sticky, tear resistant Kevlar fibers just make the laminate more inclined to stick on rocks.
Of course, Royalex or ABS boats also lose a little of that colorful vinyl when the hull passes over a rock. That lost vinyl contributes to the slippery impression. Same goes for poly boats. The hull dodges inward, and some poly stays on the rock, while the boat goes on.
It is hard to make a boat highly slippery without designing in relatively easy hull flex, plus some ability of the surface boat to leave some of itself on rocks. I have paddled boats with fiberglass composite exterior hulls, and with polyester (CAP) composite hull exteriors, and I honestly have not found them to be a problem as far as sliding over rocks with acceptably low damage.
There is one, relatively uncommon, situation where the relatively flexy nature of poly and Royalex hulls can be a problem. That is when the boat is forced into a static pin against rocks and/or logs under the force of whitewater. The depression or distortion of a flexy hull can contribute to the boat being more locked in place. In such a (rare) set of circumstances, a very stiff composite hull may make it easier for the paddler to hump loose from the pin, to extract his legs from the boat to escape, and to pull the boat loose using a z-drag and lots of help. Phoenix used to sell a layup combining polyester (CAP) and vinylester resin that, weight for weight, was as hard to tear or split as polyethelene. Because Phoenix was concerned that paddlers might be entrapped and that the layup would not break to allow an escape, they made the portion of the hull around the cockpit out of pure fiberglass, so that the cockpit could split out and allow excape. I have a Phoenix with that layup, made in about 1983, and it has lasted much longer than a poly boat would under similar use, because of its composite nature.
Never mind, I found them on the web.
If I were going to drop $4000 I'd have to look into getting an adirondack guide boat instead.....
Thanks for all of the feedback!!!!
To add a little…
Royalex as everyone stated is a good material for boats that will take constant abuse. They withstand rocks, and scrapes without “Breaking”. Note the word “Breaking”. It will take abuse and keep going, with minimal repair. it will gouge and “cut”.
Kevlar is used as a strengthening agent, It is not a very STIFF material, but it is extremely strong. In most cases Kevlar is used along with a layer of thin fiberglass cloth. Lincoln uses this layup to great success. I had a 14.5 foot Lincoln Chabeaque Kayak that weighed 33 pounds.
The outer Fiberglass layer gives the hull the stiffness that it needs to hold it’s shape. the Kevlar on the inside gives it strength.
If you hit a large rock with a Kayak that has a Kevlar inner layer, the hull may crush in, but it probably won’t split open. The Kevlar will hold it together, and keep water out. If you hit a large rock with an all fiberglass hull, it can crack & split wide open. Thus letting water pour in.
So to conclude, the Royalex is like rotomoulded boat, in that is will give and flex when you hit something, but not normally crack.
The Kevlar is used as an inner layer to give toughness to a stiff composite hull. (for safety)
I have seen all Kevlar Hulls, but have been told they do flex a lot more than a two layer hull of glass & kevlar.
i dont think you were literal when you said “ive seen all kevlar hulls…” i quit counting after about 300 hundred in the buyers guide…
have you? clairify please
Not as well as plastic
In my very limited experience nothing slides over rocks as well as plastic.
I think a strongly built kelar boat with a fiberglass or gel coat layer on the outside would make a good boat for rocky areas and kevlar and fiberglass can be repaired much easier than plastic.
I left that part out in my previous post. You can hit my plastic boat with a hammer and barely leave a scratch. With a fiberglass or light kevlar lay up you’ll leave a reparable hole. With a heavier kevlar boat you’ll leave a small scratch or a ding which can be repaired like new.
Except for Kruger boats I’m unaware of any heavy kevlar lay up boats. The light kevlar boats I’ve seen like WS kayaks and Wenonah canoes are very light and pretty fragile.
kevlar outer layer
I think most “kevlar” boats have a fiberglass layer on the outside to protect the kevlar inside from abrasion. Kevlar, when cut or abraded begins to fuzz. You can’t sand the fuzz off, sanding only makes it worse. Prevention is much better, so the outer layer is something else like glass or carbon.
In the 70’s when kevlar was first used for ww kayaks, I saw some beat up kayaks that looked like tennis balls on the outside. The kevlar was fuzzy from extensive use in rocky rivers.
I have a guide boat
I can gurantee it won’t outlast a Kruger. And the maintenance on a guideboat is rediculous. Last year my guide boat was 17 years old and looked like new. This spring it will need about 24 hours of work to look new again. 24 hours is about 9 to 12 rowing trips that must be cancelled for boat maintenance. On top of that varnishing must be done in good weather!
I’ll gladly trade my scuffed up guide boat for an even more scuffed up Kruger!
He meant composite hulls made with
only Kevlar cloth, no carbon or fiberglass. I believe Verlen Kruger made all Kevlar hulls, but he used enough layers that the hulls were stiff. Mad River, I believe, made nearly all Kevlar hulls, but they also at one time made some canoes with S-glass outside and Kevlar inside. All Kevlar hulls are just NEVER seen anymore in slalom and downriver whitewater hulls, because they are too flexy and actually not as light for any desired degree of stiffness as a mixture of cloths.
A recent development is boats made of a crossweave of Kevlar and Carbon. For some reason (maybe some weaving problem), I can’t find cloth woven of Kevlar and S-glass. But personally, I would rather just have S-glass outside and Kevlar inside.
I have a slalom c-1 made of S-glass outside and Carbon inside. Super stiff, so stiff that, so far, nothing has deflected it inward to crack the hull. But the time will come…
Ever look at the material spec sheets?
What does strong mean to you paddlers. Compressive strength or tensile strength? Your Kevlar boat is not made of the same aramid fiber as a bulletproof vest. Sorry…
Tsunami makes some thick kev hulls
but like the Krugers they are now cost around $4000.