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Foldable expedition Kudzu Craft?


Vasyl

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TL;DR - I'm trying to build a fast light foldable expedition boat. Has someone tried/done it with Kudzu Craft design. Any help/design appreciated. If you just want to see my design idea, it's in the bottom of the post.

 

I know that Jeff isn't that fond of his designs being modified. So, sorry in advance.

 

Premise / Requirements

Hi,
So here's a challenge for the community here. Or, rather it's a challenge for me and a request for some advice for you.

I'm 6' 1", 210lbs (more athletic than not). Have been paddling as a sport for a couple of years (closed trek) and finally embarked on my first self-supported expedition last year.

Norwegian fjords and some coastline.

I had rented quite a nice boat about 17-18', 22-23" with a skeg.


There were three main problems with it, however:

  1. It weighted about 58lbs empty, so about 130+ with all the equipment and supplies. I'm not that fragile, but did almost hurt my back trying to pull it ashore on the stony landing places full of sea grass. I actually broke both wheels on a mile long crossing between two fjords.
  2. The $230 for renting the boat for a week were ok, but I wouldn't mind avoiding them.
  3. The best places in the world don't have a rental. =)

 

It was apparent to me that I wanted my own kayak. And that I will probably have to build one myself.

After combing over the internet and books for a the last couple of years I came up with the following criteria:

  1. Folder / Folder-Infalter - Most of the good places here are a plane flight (Sweden, Norway, Finland) or a bus ride (Italy, Croatia) away. Besides I don't have a car and always hated kayaking having to be a "round-trip sport".
  2. Long - Slim - Light - I like Jeff's designs very much. Don't see why I would have to pay upwards of $2-3K for a commercial boat that can be "easily packed in just three 30lbs bags".
  3. Reasonably fast assembly/disassembly - ...
  4. Can be carried fully loaded - I learned that at least the commercial foldables can't/shouldn't be transported with the cargo inside. It became apparent on my Norway expedition that getting out of the water and high on the shore (mostly some boulder) out of reach of the waves is a strong security concern. It has to happen fast. Also, not having to leave your stuff behind when crossing a stretch of land really helps (I often travel alone).
  5. Small upwind sail desired - Pulling 350lbs with your torso is hard work. A small sail (no outriggers) would help with the load and also somewhat remove the risks of getting stuck in head winds (happened to me).
  6. Conditions - Rivers, some flat water, archipelagos and small sea crossing. Self-supported expeditions 5-10 days.

 

Considered boats

The Trak boats are fascinating but cost $3,6K here. So, prohibitively expensive. Ladoga and Nortik, seem interesting but cost $2-3K and apparently take ridiculously long to assemble. Can't be carried with loads. Klepper/Feathercraft... not considered (I'm not paddling a bathtub!).

 

Considered designs

Foldables: Liked Tom Yost's Sonnets, for simplicity, weight and ease for a first time builder. But read not so nice reviews about them. Also PVC apparently tends to become quite rigid in cold weather.

Non-Foldables (to adapt): Cape Falcon Kayaks seem very light and advanced. Perhaps too advanced for a newbie, especially if I would try to convert them to foldables. Also his boats tend to be a bit short. I'm positive that I can push a boat reasonably fast, especially with a bit of sail. So I like Jeff's boats more. Like his books and building tutorials. A bit less fond of using plywood though(weight).

 

Materials

 

Aluminium (Aluminum =] ): Easier to assemble. Quite costly to buy. Susceptible to galvanic corrosion in salt water (I plan quite a few sea expeditions). Which is quite a problem, according to the people in a kayaking shop here. Although I still don't get which other metals are inside the boat that galvanic corrosion could even occur.

Western Red Cedar (Stringers): A webshop recently appeared, which could possibly ship it to me. But still didn't get their pricing. Expect it to be quite a bit higher that what Jeff can get it for, as, frankly, it has to be shipped from the US to Europe first.

Guadua Bamboo (Crossframes/Ribs): I know, I know, bamboo is a controversial topic. But this specific breed seems to be quite rot resistant and available in Europe through an importer. And you know, green renewable material and stuff. =)

Polyester & so on: Nylon apparently is not suitable for foldables, PVC is not as good for cold weather. No idea where to get yet.

 

The Boat

About 17-18', 22-23" single, expeditions. Around 350lbs displacement.  Manoeuvrable enough to be able to turn in rivers or waves, but mostly suitable for going large distances in flat/open water. Rudder usage possible, especially if sail is to be used. So, basically, a LongShot type design as far as I understand. Is Long Shot an expedition boat?
Alternatively/Additionally a 20-21', 22-23" double. (yeah, I like them slim)

 

The Challenge

After going through quite a few modern designs (more or less all I could find on the net) and some old ones (there is a German site with designs going back as far as the 1920s) I didn't really find anything satisfiable. Either to cumbersome, to expensive, to weak (can't carry when loaded) or mostly all of the above.
So I would really appreciate any suggestions, links, advice, anything really. A ready-made design would be quite nice, as I'm not in any way experienced enough to introduce more than a few small tweaks without possibly ruining a boat's performance.

 

Also some constructive criticism on a couple of ideas I have.

 

Non-conventional Design tweaks

So, I liked the way Cape Falcon kayaks work with ribs, as this would allow me to use bamboo and not use plywood. He manages to build a 20' (non-foldable) double weighting only 42lbs. But ribs are not easily done with a foldable boat. But what if you fasten the ribs to high-load straps (ex. where the stringers would be). Using a couple of those would give you a 3D structure you could still fold together to be only about as long as the sum of the ribs' widths (1-2'). Pull them apart and you basically have the layout of your boat. Now fasten them to sturdy gunwales / a keel and you get a rigid structure that still has some flexibility in it (what we like SOF boats for). With tight rib spacing the stringers would be well supported and wouldn't have to be too beefy.

 

Furthermore. I assume that it would be possible to only keep the gunwales and the keel rigid and exchange the other stringers for a (ex.) flatwound PVC sleeve sewn to this straps. When inflated the sleeves would tighten the skin and provide enough distance so that it wouldn't touch the ribs when in water. Also, this inflatable stringers would be able to budge a little thus relieving punctual stresses (hitting a rock or branch) and helping to keep the skin intact. (A crude drawing of the concept will hopefully follow)

 

This is the basic idea.

Of course there are still a lot of open questions:

  1. How stupid is this idea?
  2. How do you fasten the ribs to the straps? Aluminium/stainless steel (for bamboo) rivets? Sewn on?
  3. How to you fasten the ribs to the gunwales/keel? Maybe a sleeve to push the gunwales/keel into?
  4. Can "in-skin" assembly be achieved (would keep the boat drier)
  5. Which materials to use for it all.

 

I'm finally done ranting. Any help and constructive critique appreciated!
Happy padling,
Vasyl

 

 

Kayak sketch (simplified).JPG

Edited by Vasyl
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Quote

I know that Jeff isn't that fond of his designs being modified. So, sorry in advance.

 

It is not that I mind people modifying them so much...  when you modify it, it is no longer 'my design'.  It is now a different boat and I am am in no way going to accept the liability by encouraging that.

 

You are welcome to change anything you wish, just understand that  when you do, it is your boat,not mine.  You are now responsible for the boat then, not me.

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Regardless of money I know of no foldable boat that I would call expedition.  I watched a German foldable kayak be assembled for a day trip and then packed up again .  They spent over an hour total and still were going to have to unpack it, dry it out and repack it when they got home. It weighted 80#  and stored in 3 bags.  I would rather hang a SOF from the ceiling of my living room for storage than deal with a folding boat.  Everything in boat design is a compromise and I see no good one for folding, light weight and seaworthy.

 

The small sails used on kayaks are fine for down wind and to a degree off the wind.  I can't imagine any rig that would work to weather without lee boards and/or amas and now you have to question whether you have a kayak any more.

 

I remember there were motorcycles billed as both on and off road.  I found they were equally bad at both. Figuring out what one really wants can be harder than building it some times.  You can't have it all.

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Yes that's exactly what I was referencing. The typical Klepper double with a 31" width. Not for me. And many others are like that.
There seem to be some manufacturers making boats which more resemble the plastic ones we paddle (see Trak, Nortik, Triton), but as I wrote, they easily cost double or triple of what a heavy plastic boat would cost. And certainly much more than the boats Jeff designs.

 

Yes, every boat is certainly a compromise. But for me it's more or less having a foldable or not having a kayak at all. Storage and transportation won't allow a different one.

 

Yes, I'm considering lee boards. I've seen kayak sail systems promising adequate performance with lee boards only. No amas though. As, you were saying, to me that wouldn't be a kayak anymore.

 

Certainly true, you can't have it all. Just trying to find the best compromise. =)
Thanks for the valid points.

 

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On 21.2.2017 at 11:59 PM, Wooly said:

You might want to look at the Yost boats.  Similar to Kudzu but he has some folding and inflatable designs too.  http://yostwerks.org/index.html

I did look at them. Actually considered building a Sonnet for quite some time. For the weight, ease of build and speed of assembly.
But then read some comments on it not being even remotely rigid and got a bit discouraged.

 

On second thought there is the Sea Ranger Exp.
But the frame seems quite cumbersome. Also I was discouraged by the foldables store here from using Aluminum in salt water, as well as PVC in cold weather.
Moreover, they are not cheap to get here. Nor is HDPE (as it is heavy).

Although 30lbs for a 17.5' Expedition boat sounds very promising

 

Subjectively I somehow trust Jeff's designs a bit more. Yostwerks doesn't seem to have been improved on for quite some time.

Have you had any experience with the Yost boats? Or with any foldables, for that matter?

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On 20.2.2017 at 2:27 PM, Kudzu said:

For a true expedition I go with Vardo because of its volume.  

Managed to find out which boat I was renting last year.
It must have been a Valley Etain 17.7' with a beam of just under 22" (if I get their website right).
So I would guess that the 24" of a Vardo would feel quite slow for my paddling style.

Do you maybe have some numbers for the (usable) volume for Vardo, Long Shot, Firefly, Poco Barta?
(Didn't find Poco Barta on the website. Was it discontinued?)

 

On a similar note. Have you had any experience on how long the delivery of the plans to Germany would take? Does it cost extra?

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Width of a kayak is not a good indication of the performance, it meant nothing.  Width at the waterline is a better indicator. Best is the wetted surface and the shape but no one gives that info and there is no good way to compare one to another.  I can design a 26" wide (at the gunwale) that is terribly unstable and reasonably quick too.

 

I don't have volume numbers, I just know the VARDO is the largest. The others are pretty similar to each other. Short Shot is in my opinion the most versatile but it doesn't have the volume of an expedition boat.  Of course a Valley Etain is not an expedition boat either. Poco Barta is only available as offsets in my book.

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That is of course true, shape and width at WL are key.

Precisely why I'm making all the fuss to probably buy one of your designs instead of getting one of the free ones on the Internet. =)

 

But as you are saying, overall width is the only thing indicated, so that's what I have to work with.

From what I see in the pictures VARDO looks a little bit slimmer at the waterline than the gunwales. Long Shot seems a lot slimmer at the WL than gunwales. Etain seems to have more or less the same width. Do you have actual waterline numbers/estimates?

 

I understand that VARDO is the largest, just wanted to understand by how much, when compared to the other designs and other comercial boats.


Etain might not be an expedition boat, it is however my sole frame of reference (except the different Prijon boats which I only paddled empty). So I'm fairly confident I could pack a weeks worth of stuff in a boat of comparable displacement/volume if packing wisely. And I also know the level of (dis-)comfort I felt in it when out on the waves.

That's why I'm asking.

 

How does Poco Barta compare to the others in speed and volume? I guess, a bit slower being a singlechine? Basicaly, why wasn't it "upgraded" to a full size plan)?

 

So, do you know, how long shipping of the plans would take?

 

By the way. What is the advantage of a fan-tail stern?

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Pouco Barta was designed as a free plan for the book. It is similar to the Curlew and should be a very good paddling boat. Rounded hull will be slightly faster but the difference is only noticeable to very experienced paddler or if you paddle one and then paddle the other at the same time. Even then it is not a big deal.

 

As for shipping I don't know, probably a week maybe two if Customs hold it up? I ship world wide and very little issue. Of course once it leaves the States I can't do anything.

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On 2/23/2017 at 2:51 AM, Vasyl said:

I did look at them. Actually considered building a Sonnet for quite some time. For the weight, ease of build and speed of assembly.
But then read some comments on it not being even remotely rigid and got a bit discouraged.

 

On second thought there is the Sea Ranger Exp.
But the frame seems quite cumbersome. Also I was discouraged by the foldables store here from using Aluminum in salt water, as well as PVC in cold weather.
Moreover, they are not cheap to get here. Nor is HDPE (as it is heavy).

Although 30lbs for a 17.5' Expedition boat sounds very promising

 

Subjectively I somehow trust Jeff's designs a bit more. Yostwerks doesn't seem to have been improved on for quite some time.

Have you had any experience with the Yost boats? Or with any foldables, for that matter?

 

 

I do not have any first-hand experience with foldables.  I only mention Yost because the site shows them and some details of the building and construction--I thought this might be helpful, no matter whose design you choose.

 

Also,  I would not be shy about using aluminum around salt water.  It is probably important to get the correct "grade" and not mix other metals with it.  After all, there is a huge marine boat building industry that builds in nothing but aluminum. 

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