Building my first SoF

Discussion in 'Boat and Accessory Building' started by GeroV, Dec 2, 2014.

  1. GeroV

    GeroV Paddler

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    I just recently joined the forum, and also just finished my first kayak - a CLC Shearwater 17 S&G - and two paddles. My Shearwater turned out nicely, but even before having finished that I was severely bitten by the SoF bug and wasted no time ordering Chris Cunningham's book on building one.

    I want to thank Doug (paddlesores) for his excellent writeup of his SoF build as it was a first rate build and provided really good images of how things should look. Thanks also for the offer to help along the way, Doug. For that matter, please all feel free to chip in. My Fir 2x4s should arrive later this week and if they do, I'll start laying things out on the weekend. I already have a big chunk of Ash from the canoe paddle I made for my niece.

    Here is my Shearwater and the Greenland paddle I shaved out of a piece of western red cedar.

    Gero
     
  2. paddlesores

    paddlesores Paddler

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    Looking forward to the build Gero. You'll get lots of good advice and help from the people here. Enjoy the process and post lots of pics.

    Doug
     
  3. GeroV

    GeroV Paddler

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    I now have a pair of 20' Fir 2x4s sitting in my garage waiting for me to get to work. Upon seeing them strapped to the roof of my car and learning their purpose, my twelve year old daughter asked if I would build her one her a kayak too. Relishing the thought of getting on the water with her, I said yes (I actually told her I would "help her build it"). Now this begs the question of the dimensions of the kayak. She is about 5' tall and on the slim side, so my thought was to shorten the kayak from 18' to about 14 and making it a little wider than the four fingers rule to give her a little additional stability.

    Will she outgrow the kayak? sure enough, but at that point I will wipe it down and hang it up on the wall in the house and build her another one or let her use the 18' boat I'll be building for myself at the same time.

    So my question is the following - can I figure out the spacing of deck beams and the like for the 18' and then reduce proportionally on a 14/18 basis, or should I just build two 18' boats and let her grow into them. I would like to get the basic measurements down on paper (in addition to the story pole) before I cut anything to length and get to work.

    Thanks,
    Gero
     
  4. JohnAbercrombie

    JohnAbercrombie Paddler

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    Another possibility would be to look at plans that have been built into boats - less risky than 'rolling your own', IMO. It does depend on your daughter's height/weight, I suppose...some 12 year old kids are close to 'adult Greenlander in previous centuries' height, I think.

    One site to check out is Tom Yost's:
    http://www.yostwerks.com/Kidarka.html

    Bjorn Thomasson has developed some 'kidboat' plans but they are strip-style boats.

    A number of contributors to kayakforum have built kid boats; you could ask there.

    There was a discussion here about the Raven and other boats for smaller paddlers which could give you some ideas about 'scaling' a design.

    Personally, I think a S&G boat built with cheap materials would be better for a kid/learner, but I'm not a SOF guy, so my bias is showing there! :D

    EDIT: One more thought (thinking back to my early guitar building days...): I'd recommend building those boats sequentially, not simultaneously...I duplicated some bad ideas 'building in parallel'.... YMMV
     
  5. GeroV

    GeroV Paddler

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    John,
    Thanks for your feedback. I probably will build sequentially, simply due to space constraints...

    She's adventurous, so I think she might be fine in an SoF.

    Gero
     
  6. GeroV

    GeroV Paddler

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    One thing I've noticed is that I've read about a couple of builds where people built SoF boats according to Chris Cunningham's book using western red cedar - a wood which he advises against using, and I've also read on a couple of other threads that it's not as good a wood as yellow cedar.

    Any thoughts on this from those of you who have built using WRC?
    thanks.
    Gero
     
  7. mick_allen

    mick_allen Paddler & Moderator

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    WRC is tough to bend, much better to use yellow cedar or other like say ash.
    But if you must use WRC, put the rib initially in compression, heat (or steam) and then bend while still in compression. . . . but I just don't think the boat will be as resilient to stresses with a wood species bent at the edge of it's ability.
     
  8. Redcedar

    Redcedar Paddler

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    Gunnels are the main strength members of a sof kayak .

    I did use western Red cedar for gunnels on one kayak to see how it would do and it held up ok but i consider it to be marginal at best due to its splitty nature . Gunnels have weaker spots in them as they have holes drilled in them for lashings and pegs when using traditional construction. You don't want a splitty wood therefore.

    If you want to experiment on the splitty nature of various wood species , just use some dry scraps of various species including red cedar . Take a Mora sized knife and a light baton then tap each piece of scrap on the end grain , note how much eyes widen on the piece of red cedar .

    I prefer spruce or yellow cedar for gunnels and keelson.

    Red cedar is ok for chines which I use attach to the rest of the frame by lashings only .

    For ribs and cockpit hoop air dried white oak is the best. I've used yellow cedar for most of my kayaks ribs and hoops since i can get it myself locally . I use 1/4" thick ribs.
     
  9. Astoriadave

    Astoriadave Paddler

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    Alaska yellow cedar has density 0.5 g/cubic cm, or 31 lbs/cubic ft, compared to

    0.38 g/cubic cm, or 23 lbs/cubic ft for western red cedar. I assume these are dry weights.

    Used for gunnels, I suspect the volume of wood in use is about a tenth of a cubic ft, maybe a little more, for a difference in weight of just 0.6 lbs aka 0.3 kg or 300 grams. These are rough figures.

    Pretty small penalty to pay for tne durability of yellow cedar, if you can source it. I like the yellow cedar for its toughness, but have not used it much. Were I to tackle a SOF build, I would definitely source it. I think McLanahan in Forks, WA probably can provide it. http://www.mcclanahanlumber.com/specialty.html No affiliation with McLanahan.
     
  10. GeroV

    GeroV Paddler

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    Thanks for the comments, guys.

    I spoke with my lumber supplier and he indicated that he could not get the alaskan yellow cedar (I'm on the east coast, as an FYI). He did get me fir, which I will use bearing in mind the limitations with respect to strength.

    I will be building the kayaks so that my kids have one they can use to join me on a paddle. I will be building myself one and will be using that primarily on rivers, lakes and the Chesapeake bay. that should certainly be a good test of the strength of the boat. If its rougher, I'll take out my Shearwater, but it would be a while before I go out in really rough water as I'm just getting started with the kayaking and want to make sure I know what I'm doing out there. Not interested in winning any Darwin awards at this stage.

    And besides, if I go by what Stumpy said, this will be the first of many kayaks... :cool :cool :cool
     
  11. Astoriadave

    Astoriadave Paddler

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    Gero, by "fir" I assume you mean Douglas fir. Doug fir varies enormously in its bendabilty, depending on its moisture content, whether it was kiln dried or air dried, and especially on whether it is tight grained (aka old growth) or not. I have not been successful bending it dry. Steaming may be required, except for thin stock.

    It can be difficult to source West coast woods on the Eastern seaboard. One option is to find alternates from East coast species. Check in with the crowd on the Woodenboat site and ask for suggested species. WB has a prohibition on posting vendors, so you might have to do some back channel emails after you locate a couple folks on the WB site who know where to find the wood you want. http://forum.woodenboat.com

    Also, I believe Stumpy is East coast. He may have some sources.

    Trying to make an inappropriate wood do what it can't is the path to damnation and frustration. Been there, done that.
     
  12. GeroV

    GeroV Paddler

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    Dave,
    as always, appreciate your comments. the fir would be used for the gunwales. I was thinking of getting clear pine for the deck beams and ash or oak for the ribs. The rib material would be soaked for a week and then steamed before trying to bend. Having followed Doug and Lila's build threads, I think I have a pretty good sense for what not to use for the ribs.

    I think the fir should be ok for the gunwales since the bend is not that great over the length of the boat. If, in building the first boat, it turns out that the fir is just not working with respect to holding the mortises for deck beams and ribs while maintaining its strength, I'll use the other 2x4 and make a couple of greenland paddles :cool :cool

    Gero
     
  13. Astoriadave

    Astoriadave Paddler

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    That should work, provided it is tight vertical grain fir. The gentle bend won't be an issue. The mortises may, however, if there is high runout or wide grain. Well, thinking about this, I bet the mortises will be going across the grain, so probably won't matter much whether it is tight or open grain. Is that the way you visualize resawing the 2x4s to make gunnel stock?

    Fir is a good choice for GPs. Tough, rot resistant, and strong, if the grain orientation is correct.

    I think you will have a lot of fun with these projects!
     
  14. GeroV

    GeroV Paddler

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    Dave,
    if my memory serves me correctly, the grain is fairly tight, and I will be resawing the 2x4 so that the mortises go across the grain. I'll double check though. If need be, I'll do some light lashing around the mortise joints to keep everything nice and tight. and to keep the wood from splitting.

    I need to move away from the keyboard and back into the garage... :roll: :roll: :cool
     
  15. GeroV

    GeroV Paddler

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    I got the shipping notification that my artificial sinew is in the mail. Time to get started. I think I'm going to make my kayak first so that I can get the hang of it, and that way I'll be building the one for my daughter with some experience. I would like mine to be 18' total when built, as anything longer won't fit in my garage. I don't recall seeing in Chris Cunningham's book how long the gunwales should be (I know that the stems will add about 8" each to the length of the boat) when I cut them so that I end up at the desired length. Should I reckon on losing about 6" of their length to the curve of the hull, or will it be more? The gunwales will be 3" by 3/4 (ish) - I'm ripping a 2.4 and will most likely do this by hand with my japanese saw which has a very thin blade.

    First steps will be to make the story board and then locate and mark the mortises for the ribs. I'll do these with my plunge router and 1/4" bit.

    Stay tuned, and any comments/suggestions are more than welcome.

    Gero
     
  16. Astoriadave

    Astoriadave Paddler

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    Gero,

    Have you lofted this design? What are you working from, a table of offsets?
     
  17. GeroV

    GeroV Paddler

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    Dave,
    I was going to build up the gunwales and deck beams, and then figure out how tall to make the ribs to get the right volume in the boat. I'm assuming that is what you're referring to, so no, I haven't lofted the boat yet. If I'm doing this wrong, that would be good to know. I was going to make it my hips plus four fingers on either side for the width.

    Gero
     
  18. Astoriadave

    Astoriadave Paddler

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    Gero,

    A table of offsets should let you draw out the gunwale line as viewed from above, on the garage floor if necessary, which would give you the length. Sounds like you know the maximum beam, and could pick a line you like to span the stern to bow distance if you don't want to mess with offsets.

    On the saw blade for ripping the 2 x 4, I found a thin 5 inch diameter rip blade for my table saw and used that for ripping stock when I wanted minimal kerf. Very clean cuts. A 20 ft piece of stock takes some special care no matter how you cut it. And likely an assistant if using a table saw.
     
  19. GeroV

    GeroV Paddler

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    Dave,
    understood. I had not seen the term lofting used in Cunningham's book - he has you cut the gunwales to length and then move the spreaders forwards or backwards to determine the ultimate shape of the boat, in addition to the center spreader that determines the width at the cockpit.

    I think I'll follow his method on this one as my garage floor is not one on which I can mark shapes given the configuration of stationary tools and work benches. It's all part of the adventure of building an SoF...
     
  20. Stumpy

    Stumpy Paddler

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    Sorry to be jumping in here so late, I'm a little confused... why do the stem and stern boards add to the length? I've always seen them tied into the gunwales, rather than in front or behind. Fir should be fine for the gunwales, I'd suggest ash for the ribs, and WRC for the chines and keelson, to save weight. that's only a suggestion, when you take into account that kayaks were originally built with available wood that washed up on the shore (or ice, depending on where you were), Getting too picky usually has a high price tag, if you get too dogmatic about what you want to use. as far as determining the length of the ribs, I've heard of using a piece of Romex wire to determine the longest length first, then cutting bits off to determine the shorter ones.

    Don't forget to peruse the thread "skin on frame for me!" for very detailed descriptions, and photos of different steps

    I'll check back periodically, though I've been fairly busy as a bowyer lately, but submitting a post on this thread, will keep me in the loop