C-Forum

I hinted in a previous post that I think that hull shape might have something to do with wear. I had a Detonator made of Royalex that gouged badly from easy hits and was showing way earlier than expected. My old Dagger Ocoee is holding up great but has needed patching in the chine where it has taken the most wear. I am the second owner of a Spark made of Royalite that isn't worn much at all. The previous owner paddled Class IV rivers in this boat and I have a number of Class III runs in it and even though Royalite is suposed to be more fragile it shows little wear at all (stern vinyl from the WW center). A side note: the Royalite in the Spark seems to be thicker that the Royalex in other Esquif boats and Royalex boats of other manufacturers. It is thicker than I remember the Royalite being in a Rival and Viper 12 that I have owned. Is this possible? We've all heard the story of the camo color being chosen because it had less surface drag and therefore was faster. Could it be that Jacques got a great deal on some honkin' sheets of Royalite that was supposed to be duck hunting boats?

Aluminum with a nonstick surface! With that on the inside, your boat could double as an omelette pan! But, oh, how to afix thigh straps...

sbroam wrote:But, oh, how to afix thigh straps...

100 degree countersunk rivets - just like building an airplane!

sbroam wrote:Aluminum with a nonstick surface! With that on the inside, your boat could double as an omelette pan! But, oh, how to afix thigh straps...

CAST IRON BULKHEAD!!!

Generally speaking, the camo outer layer in a Royalex sheet is acrylic, not vinyl, and acrylic is both a bit stiffer as well as more abrasion resistant than vinyl, so that probably accounts for the fewer observed scratches/amount of use in the referenced Spark. To the best of my knowledge, however, the current makers of Royalex (and Royalite) will not add the acrylic layer over what is ordinarily the outer layer of Royalite, only as an additional layer of Royalex. I assume that this is because there is some chemical incompatibilty that makes the acrylic not adhere to the Royalite material as well as it adheres to the Royalex material.

The outer layer of Royalite is Korad. This is the same material that the camo pattern is made of. Korad is the only real material different in a sheet of Royalex than a sheet of Royalite.

Korad is a Spartechs trade name for their blown film acrylic.

I understand the scratching.

But what about hulls that flex like rubber...

2opnboat1 wrote:and if it is who I think it is The boat is a Royal lite made just for team members

Yep, that's the guy. I'm sure he wishes that his sponsor made a plastic boat.

hades so do I

Spartech has heard your concerns, and just announced Royalex II, a product that will be hard and firm when new, but will slowly, over several years, turn to a soft, leathery texture.

Surely this will be the "holey grale" for whitewater boaters, who after a few years are hoping for a reason to buy a new boat.

The problem with "plastic" boats, and by this term I take it you mean PE, is that in order to make a bigger boat that is even moderately stiff in the middle so much wall thickness has to be added that the boat becomes unacceptably heavy. Note the discontinuation of several popular Royalex whitewater tripping designs and their lack of replacement in PE.

As philcanoe has explained elsewhere on the forum, using the corrugated cardboard analogy, pretty much the only way to get stiffness without using more mass of material is to separate the "structural skin" material while at the same time keeping them from moving in a shear direction relative to each other. In other words, make Royalex.... yourself.

I have a Detonator in yellow (as that is the only color they come in). Yes the vinyl skin scrapes off easily especially on the double chine area. I have not noticed any excessive "gouging" of the underlying ABS though. Every so often I just paint over the exposed ABS on the chines with some ABS slurry and it seems to keep the wear of the hull layers to a minimum. I think if we want our boats to last a real long time flatwater would be the way to go, but what fun is that? The way I look at it every material and design has its pros and cons. If everyone paddled a glass boat for a few years we'd get real good at reading the river and dodging rocks, and there would be less of a need for a "bombproof" hull material for most of us. I did suspect that the EPA rules had something to do with the "soft" royalex, so maybe they'll move the factory to China or something

Unfortunately, there are a whole lot of manufacturing steps involved in making a Royalex laminate sheet, and a mistake in any one of them can cause the sheet to delaminate. Delamination is the main cause of "soft" sheets- the inside skin and the outside skin are meant to not move relative to each other in a shear direction but if any layer of the sheet is not bonded exactly right to any adjacent layer in any particular area, then you can have relative motion between layers in the shear direction in that area and that equals "softness".

When it is all done right, Royalex is nearly an ideal material for canoe hulls, but there is no way to measure the strength of the layer-to-layer bond between every layer inside a sheet, so at the moment canoe manufacturers are stuck using what is available and assuming that someone else did everything right. Or spending huge amounts of money building roto-molding tooling to make (relatively) small PE canoes, or trying to develop proprietary materials whose properties they can control.