Naive Kayak User to boat builders asks Epoxy vs Vinyl construction

Discussion in 'Materials' started by Carl Scarbro, Nov 19, 2018.

  1. Carl Scarbro
    Joined: Nov 2018
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    Carl Scarbro New Member

    I have built a boat, but I am not a boat builder, but a paddler.

    I have been looking a sea kayak ads and noticed there are three types of composite boats generally available, wood/epoxy, vinyl resin and fiberglass (some with kevlar, carbon fiber cloth), and epoxy and fiberglass (some wiht kevlar, carbon fiber cloth, or foam). The web sites reveal only two truths about the last two constructions, the epoxy hulls are lighter and cheaper. The later seems counter intuitive because epoxy is more expensive, but maybe it is easier to use? Most of the surf skis manufacturers use epoxy for their products, most of the classic sea kayaks use vinyl resin.

    My question to you guys which one is the toughest for landing on stony beaches, the occasional 2 g crash on a rock, and easiest to repair?

    My current stead is a polyethylene boat that weighs 10 pounds more than a vinyl boat and 20 pounds more than a typical epoxy based boat. It takes a beating with ease and it you want to fill in a screw hole you use a soldering gun and piece of plastic, but getting it to the put in is work and I want a faster paddle.

    regards
    Old Paddler
     
  2. Blueknarr
    Joined: Aug 2017
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    Blueknarr Senior Member

    Welcome to the forum;

    One quick question: Are you sure it's vinyl and not polyester vs epoxy? There is little advantage to using vinyl-ester on a day use vessel. Both VE and PE could be repaired with polyester or epoxy, but epoxy needs to be repaired with epoxy. Most amateurs use epoxy so as to avoid the nasty stink of VE and PE.

    But all the talk about resin type is immaterial; it is the nature of the reinforcement fibers and extent of damage which will determine the difficulty of repair. It is also the fibers that are the greater source of the weight savings. Stronger fibers allow thinner and therefore lighter hulls. Kevlar and carbon fiber will be extremely difficult to repair with out giving up significant performance advantage.

    Durability is often sacrificed for performance. Light, thin skinned hulls are fragile. A carbon hull can be less than 1/5th the thickness of old school fiberglass. A gouge of equal depth will weaken a thick low-tech hull less than a thinner high-tech one. Your current ride is the perfect example of low performance but high resilance.
     
  3. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    Are any Tiger Shark resistant ? One chap in my vicinity recently had his poly kayak attacked by a large one ( he was berleying on an offshore reef) that punctured it, luckily for him it remained only half-sunk, it does float. The shark could not have been that hungry, or didn't like the taste of PE.
     
  4. Carl Scarbro
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    Carl Scarbro New Member


    I probably do have the materials confused. If the epoxy boats are lighter it is due to the cloth not the "glue"?
     
  5. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    Are you gonna buy or build?

    If you are going to build; plans and designers dictate.

    If buying a boat; post compares and ask specifics.

    I think your post is sort of wide open. Haven't seen too many polyethylene yaks that are made for speed either.
     
  6. Carl Scarbro
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    Carl Scarbro New Member

    I'm a paddler so I will buy. The short list are these

    Stellar 16' Touring Kayak (S16) - Stellar Kayaks offers kayaks, surf skis, paddles and accessories. http://www.stellarkayaks.com/S16-touring-kayak

    Stellar 16' Surf Ski (S16S) - Stellar Kayaks offers kayaks, surf skis, paddles and accessories. http://www.stellarkayaks.com/S16S-surf-ski

    Current Designs :: Ignite https://www.cdkayak.com/Kayaks.aspx?id=47

    https://www.epickayaks.com/v6

    one glass boat that I have paddled and liked

    Current Designs :: Sisu LV https://www.cdkayak.com/Kayaks.aspx?id=55

    and a PE boat that looks like it is fast enough for me just maybe to much weight as I delve into old age.

    https://tahe-marine.taheoutdoors.com/tm_en/reval-midi-pe.html

    I have paddled the Sisu in conditions and it was fine boat. No rudder however, and I kayak sail, too. The rudder helps down wind.

    I am interested in 16 foot boats (my garage) with beams of 23 inch or less (more speed).

    The Epoxy boats seem to be in another universe being a little cheaper and lighter than the typical composite british sea kayaks I see on the great lakes. They come with rudders for the most part.
     
  7. Carl Scarbro
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    Carl Scarbro New Member

    I think I heard of the that incident. I would be scared.
     
  8. fallguy
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    fallguy Senior Member

    I am not a kayak guy enough to steer you.

    The epic in nomex is sort of a dreamy boat at half the weight of the PE, though.

    I have a 65# canoe and it is pretty hard for me to single carry, and before my hip failed; I was a beast.
     
  9. Blueknarr
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    Blueknarr Senior Member


    One comparison is to adobe bricks. Straight mud is weak, so a wall made from them must be very thick and thereby heavy. Add some straw and the blocks are stronger so thinner or taller walls are possible. Swap nylon twine for the straw and the improvement is magnified.

    Pure resin is relatively weak. Just like adobe, the addition of fibers greatly increases the composite"s strength. Fiberglass hulls can be thinner and thereby lighter than un-reinforced resin. Super strong fibers can be thinner and lighter still.
     
  10. Deering
    Joined: Feb 2005
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    Deering Senior Member

    I’ve done a lot of kayaking. If you’re looking for a boat that can bash into rocks and make surf beach landings, buy a polyethylene boat. There’s no glass composite boat that can take anywhere near the amount of abuse that a poly will. A bit heavier but not enough to really matter for general touring. My favorite are Necky kayaks - highly refined hull shape.

    If you’re determined to go lighter, go with a carbon or Kevlar epoxy hull. Carbon will be the lightest and easiest to repair with a bit of epoxy and glass cloth. Easy to take a small repair kit with you. You can always have an added layer of material on the keel as a wear surface.
     
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  11. rwatson
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    rwatson Senior Member

    Poly is really heavy.
    "a 10 feet polyethylene fishing kayak can weigh over 60 lbs. making it heavier than a 13 feet touring kayak made from heavy-duty PVC which weighs around 30 lbs." A wood/epoxy kayak is even lighter - and if it's glass/foam, even less.

    I wouldn't underestimate the benefits of light weight. After a long trip, the last thing you want is manhandling the beast back to the transport, especially if it has to go on high racks. Getting it down to the water from a remote car park is a real nuisance.

    The other problem with "plastic" boats, is their continuing degradation. A 4 year old plastic boat will have all the knocks and dings over the years, and end up looking really trashy, while I will be epoxy/filling and painting my wood strip Epoxy 16ft Canoe , that weighs about the same as 10ft plastic version, and it will be looking like new every year. Being able to effectively repair dings and knocks back to new, means that the market value remains better. On top of that, the "fuzzy hull" syndrome of plastic canoes makes for slower paddling, where getting back to mirror finish means optimal performance. Some plastic boats will also harden and crack after exposure to sun after a few years.

    The other really big thing about epoxy/timber canoes is their ability to be modified safely and professionally at the whim of the owner. Depending on your preferences, everything from extra hatches, inboard pumps, bulkheads, gear points etc, are easy additions by the owner.

    For someone willing to DIY, Epoxy/Timber hulls cost a lot less if you build them yourself - even from a precut kit. I understand the OP isn't keen for this, but maybe there is a competent friend that wants a new project ... ?
     
  12. fallguy
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    fallguy Senior Member

    Great points; the PE is sort of a bash it boat and the epoxy boats are all repairable.

    And you can build really great kayaks from okume and epoxy and light glass for like 25% of the cost.

    But building a repairable boat is also wise. The lifespan of the PE will be less almost certainly.

    A well built epoxy yak will probably outlive you.

    I say spend a few extra bux and buy that beautiful epic nomex boat.

    I still can't get used to the sit atops, though.
     

  13. Deering
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    Deering Senior Member

    Rwatson, no argument with any of your points. My point was that there’s really no comparison between composite and PE when it comes to hard abuse. Where I paddle many of our beaches are rocky and unkind when beaching or launching. I’ve built several kayaks and rowing boats out of plywood/glass/epoxy and can attest to their lighter weight. Building from precut kits is definitely faster and less prone to error. Any damage that penetrates through the glass into the wood has to be promptly repaired before the wood starts to saturate.

    One trick I’ve learned that helps reduce damage is to coat the bottom with an epoxy/graphite layer. Just thicken the epoxy with graphite powder and roll it on. It creates a slippery sacrificial layer that ‘lubricates’ any scraping over hard things. It can be easily sanded smooth and relayered. This is something that could be done to any composite kayak, self built or purchased. One important consideration is that any glass repairs will require sanding the graphite completely off or it will interfere with bonding the new reinforcement to the hull.

    Incidentally, Northwest Kayaks makes carbon fiber hulls that are shockingly light, 10lbs less than their glass hulls.
     
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