Small Kayak - Under 13 feet - Stability?

Discussion in 'Stability' started by millionswords, Dec 16, 2008.

  1. robherc
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    robherc Designer/Hobbyist

    Hmmm, I'd think a bandsaw COULD work perfectly well for this, with the right blade. I actually managed to cu 2-inch tall letters (the whole alphabet) on a bandsaw once...painted 'em up & gave 'em to a younger cousin for learning toys... Anywise, the bandsaw would have to have a fairly narrow blade on it, and 10^6sword would have to have ACCESS to the bandsaw, but it seems a viable option.

    That sounds like a viable way to me...I'd recommend hacking out the rough shape (just don't get too close to your lines) with the bowsaw for speed...then trim it up nicely with the coping saw.

    Alan, Unless I misunderstood his intents...he is wanting to cut curved surfaces here. A had saw is great for straight, but isn't worth diddly for cutting out the letter "C". I think the coping saw/bow saw are his best bets there, short of procuring a jigsaw or reciprocating saw (not a sawzall, the bench-top ones) that is. I could be wrong, but that's the impression I got from his post.
     
    Last edited: Jan 7, 2009
  2. ancient kayaker
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    ancient kayaker aka Terry Haines

    The problem with using a bandsaw is cutting the inside edge of a closed shape, as the frames have internal holes for lightness and to accommodate body parts.

    Actually the hull is hard chine so the frames are made up from straight edges. However, the hand saw won't cut the inside line.
     
  3. millionswords
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    millionswords HomeMade Kayak?

    Just to clarify!

    I have to cut something like this.
    This is not off the SeaBee but just like it.
     

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  4. robherc
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    robherc Designer/Hobbyist

    hmmm...ok, I was thinking canoe....where your frames would be fairly simple "C" shapes...so my last post may have been a bit misguided.

    Best scenario:
    1. Cut out rough outside shape with handsaw, circular saw, or table saw
    2. Smooth out outside shape with coping saw or jigsaw
    3. Drill holes at "corners" of inside cut
    4. Cut out inside opening with coping saw & bow saw, or jigsaw

    Seem like that'll work for you?
     
  5. alan white
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    alan white Senior Member

    More than one cutting method is required. A lot of different saws make work easier and more accurate. I can't over-emphasize the value of a power jig saw. A good one costs a lot here ($159.00 US for my Milwaukee) but you can also buy a cheap one that will do the job nicely for $50.00 here.
    Good quality non-electric saws, whether coping saws, handsaws, keyhole saws, jap pull saws, or back saws, are actually MORE costly if you need several to do the many types of cuts required to shape the frames shown in the pictures. Yes, you could buy low quality saws, but they will be a big disappointment and are usually not even worth sharpening.
    The advantage of an electric jigsaw lies in the many choices of blade types you can buy (narrow blades for tight curves, wide for straight cuts) and the price of the blades is very reasonable. Especially when a kit of blades is purchased, the price per blade is very cheap even with good steel.
    If I had to choose one saw to build a boat, I would choose an electric jigsaw without hesitation.
    I don't know which brands are available in India, but it's best to stay away from any power tool you can't find tested somewhere on the internet.
     
  6. ancient kayaker
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    ancient kayaker aka Terry Haines

    One other thing on buying a jigsaw; if you have a choice get one that has an orbital cutting action.
     
  7. Squidly-Diddly
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    Squidly-Diddly Senior Member

    I have plastic 9' x 34" SOT & I'm 250lbs

    I paddles just fine and feels safe and stable.

    Maybe I'll post pics if I can figure out how to do that in this site.

    Last time I built a fabric over frame kayak with white PVC piping and nylon, I was surprized at how much the water bowed in the skin. I then covered the skin with one layer of fiberglass and resin and that was a huge improvement.


    Many short and stable kayaks(designed for fishing) use a 'twin hull' design where the center is concave.
     
  8. ancient kayaker
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    ancient kayaker aka Terry Haines

    My first kayak was 9.3' x 30", and very stable. Not very fast though. You can post pictures by clicking on "Go Advanced", then click "Manage Attachments". That will open a popup that will enable you to browse, select and upload files.
     
  9. messabout
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    messabout Senior Member

    I have been watching this thread since its' beginning. As it progressed, I gathered that the desire is: build a small boat capable of carrying camera equipment and a paddler, while operating on canals and other protected bodies of water. The boat must be light, easily transportable, convenient to store, very economical construction, can be built with very few tools, can be built by a person with limited construction skills. Does such a boat exist??? Yes! A coracle is such a boat.

    Coracles are sauce ror dish shaped boats that were probably one of mans earliest inventions. Archaelogical evidence dates them back as far as 8000 BC. They were and are used in locations throughout the globe. In Iraq, they are called Kodru, In the British Isles they are Coracles, In India they are called Parisal.

    The Parisals use split bamboo for framing. It is woven into an intricate pattern to form a somewhat hemispherical frame. In the past, water buffalo or ox hide was used for the skin. These days sack cloth is used and it is waterproofed with bitumen. See www.wikipedia.org/wiki/bitumen. Parisals are still in use in southern India as a tourist ride on the river Couvery. A Vietnamese Coracle is also made largely of bamboo with some rattan. The waterproofing is made from bitumen mixed with ox dung and resin from the Rei tree. (the ox dung statement is not a feeble attempt at humor. That material apparently has some useful qualities for such a purpose). These boats are still in use along the coastal region in places like Nha Trang on the river Cai. In the war, these boats were actually used to lay mines.

    Such a boat was used by the mother of Moses when she layed him in the bull rushes. At least that is what is said in the christian bible...Exodus chapter 2 verse 3.

    The Coracle is of such a modest weight that one carries it on his back. They usually have straps of some kind into which you put your arms while carrying the boat. The single thwart usually has a slot or hole in it. One end of the the paddle is placed in the hole and the other end extends over the shoulder of the person carrying the boat. That makes a handle of sorts, to control or balance the boat.

    Small Coracles are a little over one meter in diameter. There is much freedom in deciding the size to build. Large ones are said to have been capable of carrying 10 or more people at river crossings and such.

    Tibetans use boats of the Coracle type and general construction, to navigate in some of their far removed locations.

    These boats were used by native Americans of the Hidatsa and Mandan tribes. They lived on the northern plains of this continent. There were very few trees in those laocations so they did not build dugouts or birch bark canoes. They simply used what they had to work with. Willow perhaps. The Coracle of America was called a "bull boat". It was the only one of its' type to use animal hide with the hair on the outside. That method seemed to make a hydrodynamic difference. Of course the builders were unaware of that kind of science. They just knew that it worked a little better that way. The tail of the animal was left in place on the bull boat. It was a convenient handle for dragging the boat up on the beach and it probably was trailed astern when under way. No doubt the tail helped the boat track better.

    These boats are still in use for fishing in some of the coastal villages of Wales. There are tales that claim these boats have crossed the English channel. ( If true, I suspect that the paddlers chose their weather carefully)

    A Coracle museum is located in the Welsh village of Cenarth on the Tefi river. See: www.coracle-center.co.uk Millionswords might not choose a boat of this type, but a few of us might be interested in exploring the capabilities of this ancient watercraft. Who knows? maybe we might even build one. Sounds like fun to me. Those of you who know about the designs of Platt Montfort will get ideas about geodesics and modern coverings.
     
  10. ancient kayaker
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    ancient kayaker aka Terry Haines

    Messabout: thanks for an interesting post. I was under the impression that the coracles of the UK used animal skins but I could be wrong. This link has information on coracle building as well as other small boats-
    http://home.clara.net/gmatkin/freedes.htm
    Propelling a coracle is a challenging task, but I have seen an expert move one of these ungainly craft at a surprising clip.
     
  11. millionswords
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    millionswords HomeMade Kayak?

    Coracles - Parisals

    :) Messabout!!

    Certainly I wont choose the Parisal.
    Why?

    1. Not stylish :D
    2. It is not steerable with less effort,
    3. It wont stay stable without effort, needs constant correction
    4. I will get a headache sitting on it, even with an expert propelling it. Rotates the hell out of you :))
    5. It is not easy to build like you might think.

    Building a parisal:

    You might need hundreds of strips of bamboo, that is sanded on edges to avoid small bristles. And combing them together without gap needs an expert with experienced hands. Lashing is minimal, actually there is no lashing in some parisal i have seen, it is combed in such a manner it don't need lashing. It is a piece of art in itself. Then the outer fabric is sometimes tarp, canvas tarp, or just jute bag, hemp cloth, and covered with " tar" which is bitumen as messabout mentions. Very cheap to make indeed, and lasts freaking long! easy repairs, no or least maintenance needed. It can capsize easily, and usually people with experience can recover form capsize in no time.

    I have had some real good time on parisals, and its fun. Will try my hand in propelling it sometime when I see it next.

    Not for me - messabout!

    http://img390.imageshack.us/img390/1822/img3176wx2.jpg
    http://lh5.ggpht.com/_m_p3RoutWkw/Ra5tzhX0pWI/AAAAAAAAAec/EnW5Fnt1p6U/DSC02791.JPG
    http://en.wikipedia.org/wiki/Parisal
     
  12. ancient kayaker
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    ancient kayaker aka Terry Haines

    One is truly a work of art, the other an article of work! What else will I learn on this forum?

    Occasionally when I leave a dock I need to work out sideways to avoid hitting other boats nearby. I use a sculling stroke to do this, it is surprisingly powerful once I got the hang of it, and much more stylish than shoving off against the dock! The underwater path of the paddle is a figure of eight. It is awkward to do with a double paddle however. When I sneak up to wildlife with a camera and canoe I use the indian or underwater stroke in which the paddle does not leave the water so less motion is visible to shy waterbirds like herons, and no splash is audible. The underwater path of the paddle is somewhat circular.

    I assume the skulling stroke is used for the parisal and coracle. I would not like to have to do that for an extended period though, very tiring. Also if I had to lean forward to use the stroke at the bow it would be rough on my back.

    1E6swords: how is the boat coming along? I noticed that the model had frames made of short, straight pieces, does that mean you have given up on bending bamboo? I think that would be a pity as it could make for a very elegant boat.
     
  13. millionswords
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    millionswords HomeMade Kayak?

    hi AK,

    Yes. Not going to heat bend the bamboo.
    I thought it would be good to heat bend a strip of flat wood, but not a cylindrical bamboo.

    And more over the heat bend will not give hard chines for me.
    The plan is to make a hard chine kayak. Even strips split form a larger bamboo, bent to make ribs wont work for a hard chine.

    I'm following the Johansen Kayak building, which was used by Nansen in his Fram Expedition. Fram171 is the plan I try to replicate.

    Still options are open, I keep thinking of a plywood cross section, but might just do it like Johansen and Anders Thygesen (norway).

    Will get back to you with some pictures of materials procured in few days.
    Managed to get a 15 foot bamboo, 40mm in diameter, almost same dia till the 13 feet length.

    Others in the market were too thick or brittle, expecting to see new bamboo in the market in the next few days. Will visit again and check for the right size and length. Once procured, work will start!

    A power drill, cope saw, hand saw, bow saw and a few chisels are in hand for tools. Guess I wont need all of them here, but this is abundant tools for this method of construction.

    I have roped in a friend to help me out, we will be working on week ends form now on. Lets see how it all turns out!
     
  14. messabout
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    messabout Senior Member

    O.K. Millionswords I agree that the Parisal might be a ***** to paddle in a straight line. And, indeed they are neither as stylish or as efficient as a decently built kayak. Some of the Coracles were not round but somewhat more boaty in appearance. Were I to build one, I'd surely try for the kind that is longer than it is wide. It seems that neither of us are going to build one of primitive things.

    You must have done some good research in order to find descriptions of Nansens boats. Many people are not even aware of Nansens exploits and his incredible dedication to survival in the Arctic. He was one tough dude.

    AK, have you experimented with a Yuloh for sculling? It is a marvelous propulsion tool and it can be used for long periods without excess fatigue. It is not a prime candidate for kayak propulsion because the user usually stands while sculling. Talk about sculling, you ought to see 9 year old Bahamian kids scull Abaco dinghys. They make the boat go fast while making it look absurdly easy. Some of the dinghys do not even have notches or yokes on the transom. I wish I could do that.
     

  15. millionswords
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    millionswords HomeMade Kayak?

    Messabout,

    If that is what you feel, not re-building a parisal, picking the idea from it.
    Yes that is doable, at the cost of some serious knitting work, we can make something like a strip-built Kayak.

    With some Lofting from a decent Offset table, we could start with the knitting of the hull (no gunwales at this point) and once the knitting is over, few long strips of bamboo can be lashed together as gunnels and the rest is history!

    Hope these pictures make the above clear:

    http://www.modelboats.co.uk/news/Images/Cor20Aug08_001.jpg
    http://www.nancarrow-webdesk.com/warehouse/storage2/2008-w30/img.278893_t.jpg
    http://oziahz.tripod.com/blog/BasketWeaving.jpg
    http://www.theartplacetoday.com/sites/r_a_hansen/_files/Image/Basket weaving 012.jpg

    http://images.pictopia.com.edgesuit...fp:862862&size=500x500_mb&re=1&m=1173485448.0
    http://www.foei.org/en/get-involved/photo/gallery/51.jpg/image_preview

    What you above are all basket making with bamboo strips. There are made in circle shape, what messabout proposes was to make it little longer, thats what I see from the river-Teifi shots from wikipedia. [http://en.wikipedia.org/wiki/File:Coracles_River_Teifi.jpg]

    If we can manage to hold the mold in proper shape with some technique, we can build a Kayak in this principle, though the bottom of the kayak would be heavy, if closely knit!

    Waterproofing with Canvas, painting, fiberglassing the bottom all can happen as desired! May be I would add a stringer to the sides and a keelson?
     
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