Explorer vs Legend

[Dee Hall]

I've been doing a lot of work in the last year with these resins and can shed some light on why the polyester and vinylester resins are used in mass manufacturing of seakayaks - cost. These resins are a lot less expensive and they can be made to reach full cure much faster so they spend less time in the mold. Otherwise these resins don't have a lot of advantages. Epoxy's advantages include:

Much stronger

Doesn't use MEKP (very toxic)

Much less fumes

Shrinks less

Hardener ratio easier to measure

Resin has much longer shelf life (won't harden without hardener)

[djlewis]

Apropos of the cost issue, how does the cost of building a kayak break down between labor and materials?

My uneducated impression was that it's the labor that makes composite boats expensive, and conversely the lesser labor that makes plastic molded ones relatively cheap. So, of the, say, $2500 cost of a new composite boat, how much is due to labor and how much to materials?

Also, is the labor significantly different with different materials -- for example, does it take longer to build with Kevlar than fiberglass?

And, how much labor is there in the "trimmings", apart from making the basic hull.

And, what's the cost difference -- per boat -- among various materials. Dee says Epoxy is more expensive than polyester, but how much expense would that add to a boat?

--David

[markstephens]

Wow, and I thought nobody was interested in this thread.

Brian, question:

"Once epoxy is cured, it's completely inert and non-toxic."

Good to know. What about sanding? Obviously a dust mask is the minimum one should wear when sanding anything, but I usually wear the organic respirator when sanding stuff like gelcoat. Should I wear it when sanding epoxy?

P.S. - Hope my next post isn't from a prison cell!

[Suz]

It wasn't lack of interest, just not enough people with NF Legend experience.

Personally I find the deck height to be way too high in the Legend. I sat in James Kennedy's this past Saturday and found that it comes up on me at about mid back and my rolling preference is a lay back so it made it awkward to roll the boat. James is MUCH taller and finds he can not do lay backs in it either.

When I shrunk and started to fall out of my Argonaut, I bought the Explorer. I haven't spent any time in the Aquanat but find the Valley deck height to be higher than NDK and therefore the NDK boats fit me better.

Suz

[Dee Hall]

>Wow, and I thought nobody was interested in this thread.

>

>Brian, question:

>

>"Once epoxy is cured, it's completely inert and non-toxic."

>

Epoxy has excellent resistance to water, chemicals, oils, etc. Not so good resistance to UV.

>Good to know. What about sanding? Obviously a dust mask is

>the minimum one should wear when sanding anything, but I

>usually wear the organic respirator when sanding stuff like

>gelcoat. Should I wear it when sanding epoxy?

>

An organic respirator is overkill. If the resin is fully cured, the particles are large and a good dust mask is sufficient.

[Dee Hall]

>Apropos of the cost issue, how does the cost of building a

>kayak break down between labor and materials?

>

>My uneducated impression was that it's the labor that makes

>composite boats expensive, and conversely the lesser labor

>that makes plastic molded ones relatively cheap. So, of

>the, say, $2500 cost of a new composite boat, how much is

>due to labor and how much to materials?

>

There is more labor involved in making a composite boat which is made in several parts (hull, deck, coaming), and then cut and put together by hand. If it is a hand layup like most of the British boats, then it is even more expensive. The vaccuum-bagged layups go faster, require less resin (most of which comes from the fibers, not the resin), and have better quality control (fewer voids, more consistent thickness, etc).

On top of that, the gelcoat, fiberglass, and resin are much more expensive than polyethylene.

>Also, is the labor significantly different with different

>materials -- for example, does it take longer to build with

>Kevlar than fiberglass?

>

No. Kevlar can be slightly more challenging when doing a hand-layup because it absorbes a lot of resin and then floats, but most Kevlar boats are vacuum-bagged.

>And, how much labor is there in the "trimmings", apart from

>making the basic hull.

>

Don't know.

>And, what's the cost difference -- per boat -- among various

>materials. Dee says Epoxy is more expensive than polyester,

>but how much expense would that add to a boat?

>

From a quick check on the web, about $100-200. However, gelcoat is incompatible with epoxy. Now you need some other type of hard UV protectant, or a layer of something between them. Now you've added an additional, unknown cost.

[Bob C]

Both of Deb's boats -- P&H Vela and Bahiya -- are hard chined and she's never had any trouble bracing in or (finally) rolling either one. Her first "serious" ie Fibreglass boat was, as was mine, a soft-chined CD Slipstream that would put you in the water as soon as look at you. We both learned to paddle in these boats but don't miss them now. I paddle a Tempest165 and am very happy with its bracing and rolling abilities, and it's a moderate chined boat. Brian -- and Alex at NESC -- is right. There's a lot to how the boat is designed and how you paddle it as to how it will respond to you and to various conditions.

[Guest guest]

Brian,

Well ok, I'll keep the debate going..

I get my information from years of boat building. So I can't buy much of what you say, from reading a web site.

Have you ever actually built a composite boat ? Not just painting out a layer of glass on a wood boat, or a patch or two, but bent over the two halves of an open mold for 8 to 10 hours or more ? The composite process is non stop, to lay-up both hull and deck, trim it and seam it when the resin it still soft and accepts a bond? Have you put your head in the cock pit of a fresh lay-up to push the resin dripping seam tape out to the ends with a brush on a stick?? I've done this many times, using a variety of resins.

There is absolutely no racing influence in any of these boats, by the way.

Do you know what a racing kayak looks like? K-1's, Surfskis, etc?

No 21'' wide sea kayak of any kind is for racing, please..!!!.

Epoxy may smell better to you, but it can cause vicious skin reactions, both the exposed skin and to the tissues of the lungs. I've seen it, and it has an accumulative effect, you become sensitized to it from prolonged exposure.

Expense has noting to do with it. It's performance and consumer demand. Race boats are made of carbon and it's more expensive than glass, but the consumer will pay. The consumer would pay for epoxy too if it present real benefits for those using these products, but because most sea kayaks are treated like prized possessions, they do fine with the safer polyester resin , which does stink but is actually much less hazardous to the fabricator.

[wilsoj2]

Here is the information, from the NDK site, on the impetus and origin of NDK boats:

"Soon after this Nigel wished to set up his own kayak school, but was put off by the cost of buying a fleet of boats for the centre. Using his practical experience gained whilst on the sea in demanding conditions, both of the limitations of other brands and some new key ideas, and also helped by a friend who was very skilful with the design as well as paddling ability, Nigel built his own fleet of kayaks and the first Anglesey Sea and Surf Centre was started.

These very first kayaks were built to withstand the constant use and abuse by groups at the centre and also incorporated two new ideas. An off-set day hatch to enable the unsupported paddler to access provisions whilst afloat, and the keyhole cockpit in a sea kayak, which compared with the original very small ocean cockpit, allowed for a faster, easier entry and exit, to and from the kayak. Not surprisingly, in hindsight, those who came to the kayak courses held at the centre liked the kayaks, particularly the qualities of speed and stability. The demand increased and NDK was officially registered on the 7th May 1993."

I find the reference to speed interesting as the Explorer is truly more sluggish than the Valley boat it served to displace (the Nordkapp). The note of stability is sensible as the Explorer has infinitely more primary than a Nordkapp. One would have to be sadistic to put novices in Nordkapps. One would have to have no sense of balance to capsize an Explorer

[Bill Gwynn]

You are correct that VCP is changing their kayak line to Valley Sea Kayaks (VSK), but, Valley Canoe Products (VCP) will remain and carry their line of other accessories. VSK does have a new website http://www.valleyseakayaks.com/

[Brian Nystrom]

No Ken, I haven't built any composite boats, but one doesn't need to build them in order to understand the properties of the materials involved. Composites are a mature technology that's widely used and information about them is readily available to anyone who seeks it out. I've worked enough with epoxy and polyester resins to know which I prefer to work with.

While epoxy CAN cause skin reactions, it is not inevitable that it WILL do so. Sensitivity varies from one person to the next. There are people who've built boats with epoxy for decades and have never had a reaction to it. On the other hand, there are a small number people who react to it immediately. For the average person, all you need to do is keep the components and uncured mixture off your skin (gloves and long sleeves) and you'll be fine. Thousands of people build wood/epoxy boats annually and very few of them have any problems with it. Bring up the topic on any boat building forum and you'll see. There's no need to blow the possibility of skin irritation out of proportion.

By comparison, polyester resin is NOXIOUS, period! There is no way I'd ever work with it without a respirator on. Perhaps it's less likely to cause skin reactions (I don't know if that's true or not), but there's no disputing the difference in fumes. It also produces noxious outgassing for years, which epoxy doesn't. Just open a hatch on any boat built with it and that's quite evident. Use whatever you prefer, but I'm not buying the argument that polyester resin is safer nor that safety has anything to do with why it's not in wider use in commercial boats. The two have different safety requirements, but that's all.

As for Tideline's boats, I have no axe to grind for his designs and I wasn't comparing them to surfskis. What I meant by "racing influence" was that the "19" has a long waterline for it's length, a narrow beam, rounded hull and low stern that are similar to racing boats. It strikes me as being somewhere in between typical sea kayaks and full-on racing boats in terms of design. If that doesn't appeal to you, fine, as it doesn't appeal to me, either. My interest is in the fact that the hulls are both light and durable. I emailed Pat and he's considering building a more typical sea kayak design in the Explorer/Aquanaut class. That should be interesting, at least for those of us who aren't paddling surfskis full time. ;-)

[Brian Nystrom]

If epoxy is fully cured, the dust is inert and will not cause any kind of skin or lung reaction. The key is that it must be "fully" cured, which can take anywhere from days to weeks, depending on the ambient temperature and the nature of the particular epoxy. Regardless, I would strongly recommend a good dust mask when sanding epoxy, polyester, fiberglss, wood or anything else that produces significant dust. I don't mean the paper masks, either, as they only block the largest, least harmful dust particles. There are respirators made specifically for dust, or you can get dust cartridges to fit on most organic vapor respirators. I have one of each, as I find it more convenient to change masks than to change cartridges.

[Brian Nystrom]

When it comes to building anything, time is money. Molds are expensive to make and maintain, so companies are not going to have a lot of them (probably only one per model). If you have a choice between using polyester resin which cures in say 4 hours vs. epoxy which takes 8 hours to cure, it makes economic sense to do the former since you can build twice as many boats in a day. Epoxy is also much more demanding of mold prep, since it bonds to other materials (like those in a mold) better than polyester, which increases maintenance costs and prep time.

Epoxy and gelcoat are not absolutely incompatible, but gelcoat won't bond to epoxy that isn't fully cured or vice-versa, so they won't work together in the wet-on-wet layup technique used for building composite boats. Epoxy bonds fine to fully cured gelcoat and there are intermediate materials that can be used between them, so it is possible to build epoxy boats with gelcoat, but it's more complicated, time consuming and expensive than using polyester or vinylester resins that are 100% compatible with gelcoat and don't require special steps in the layup process.

[Brian Nystrom]

When I first demoed the Foster boats, I tried the Silhouette which fit fine and had a nice, low aft deck. Then I jumped into a Legend, which felt big and loose and had an aft deck that was too high for my taste. I did't even bother to try the Shadow, as I knew it would feel cavernous.

[jason]

I think the fit of the shadow 100% depends on your body size/shape. For me the shadow is anything but cavernous, I just sqeek into it and very much enjoy the boat. I wouldn't mind if the aft deck was an inch lower but I love the boat.

-Jason