Baidarka Offsets

Free boat plans for building a strip-built baidarka style sea kayak

19' long by 17 1/8" wide

A table of offsets for the Aleut baidarka (MAE 593-76) collected on Akun island in the Aleutian Islands in 1845 by the Russian explorer I. G. Vaznesenskii. Based on offsets published by David Zimmerly in Qajak: Kayaks of Siberia and Alaska. These offsets have been developed with a minimum change from the originally published dimensions. An Adobe Acrobat file of the drawing I referenced is available on Zimmerly's site.

These offsets differ from those published by Zimmerly in that the stations are spaced every foot and they are corrected for the thickness of the strips. These offsets are adapted for a 1/4" skin thickness so they can be strip built. All units are in inches unless otherwise specified. The form locations are in feet starting from the bow of the finished boat. The hull shape has also been smoothed out to eliminate the multi-chined sectional shape.

For instruction for how to read and use these offsets please refer to my book.This book also includes free offsets for three other kayaks.


©2000 Nick Schade
All rights reserved  
Form Location (ft)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Buttocks
Deck Peak
4.17 4.27 4.37 4.49 4.64 4.81 4.99 5.20 5.43 5.69 5.92 5.80 5.37 5.10 5.00 5.06 5.30 5.64
Keel
-0.89 -1.88 -2.51 -2.89 -3.12 -3.32 -3.48 -3.60 -3.68 -3.74 -3.77 -3.77 -3.75 -3.71 -3.65 -3.57 -3.48 -3.36
1
3.09 1.54 -1.55 -2.24 -2.63 -2.90 -3.10 -3.26 -3.36 -3.43 -3.47 -3.48 -3.45 -3.40 -3.30 -3.14 -2.94 -2.67
2
  2.27 -0.46 -1.57 -2.13 -2.47 -2.73 -2.91 -3.04 -3.12 -3.16 -3.18 -3.15 -3.07 -2.94 -2.70 -2.37 -1.95
3
    1.19 -0.86 -1.61 -2.04 -2.34 -2.57 -2.71 -2.80 -2.85 -2.87 -2.83 -2.74 -2.55 -2.23 -1.77 -1.15
4
      0.25 -1.02 -1.58 -1.94 -2.21 -2.37 -2.47 -2.53 -2.54 -2.49 -2.38 -2.14 -1.70 -0.95 0.40
5
      3.14 0.03 -1.02 -1.52 -1.83 -2.02 -2.12 -2.19 -2.20 -2.13 -1.97 -1.58 -0.76 1.08  
6
        3.23 0.06 -0.92 -1.39 -1.61 -1.72 -1.78 -1.72 -1.51 -1.18 -0.48 2.44    
7
            0.48 -0.58 -0.91 -0.99 -1.00 -0.85 -0.44 0.57        
8
                1.56 1.32 1.67 2.83            
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Waterlines
3
0.88 2.51 3.81 4.97 5.96 6.76 7.41 7.90 8.16 8.22 8.19 8.02 7.73 7.33 6.78 6.08 5.28 4.44
2
  1.61 3.48 4.73 5.75 6.59 7.29 7.81 8.05 8.10 8.05 7.88 7.59 7.21 6.67 5.94 5.15 4.35
1
0.15 0.65 2.86 4.42 5.49 6.39 7.13 7.69 7.92 7.95 7.89 7.72 7.44 7.08 6.54 5.77 4.98 4.22
0 (DWL)
0.18 0.79 2.24 3.82 4.98 5.96 6.77 7.38 7.66 7.72 7.67 7.50 7.21 6.84 6.27 5.46 4.63 3.82
-1
  0.55 1.54 2.81 4.03 5.02 5.89 6.58 6.90 6.99 7.00 6.86 6.55 6.17 5.60 4.80 3.95 3.14
-2
    0.54 1.36 2.25 3.08 3.86 4.57 5.04 5.33 5.51 5.50 5.29 4.93 4.32 3.46 2.64 1.94
-3
        0.25 0.76 1.27 1.75 2.12 2.37 2.53 2.57 2.47 2.22 1.82 1.33 0.88 0.53
  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Sheer
Offset
1.51 2.74 3.97 5.10 6.07 6.84 7.47 7.95 8.21 8.29 8.27 8.10 7.81 7.39 6.84 6.15 5.36 4.49
Height
3.67 3.63 3.62 3.61 3.61 3.61 3.62 3.62 3.63 3.63 3.63 3.63 3.62 3.62 3.62 3.63 3.64 3.67

For more information on how to read the table of offsets please refer to my book. The deck is slightly "V" shaped and is drawn as a straight line from the deck peak to the sheer line. The finished sheerline will be completely horizontal. The differences in heights in the table are due to the varying angle between the deck and the hull. You can probably approximate it with all the heights exactly the same. You should be able to copy the above table and paste it directly into a spread sheet for scaling and plotting. Here is a comma delimited text file with all the numbers in a little bit easier format for a spreadsheet.

The forms are spaced every 12 inches starting with those on the left. The horizontal dark blue line corresponds to the Datum Water Line (DWL)

I have also created an Adobe Acrobat file with all the forms drawn out. This is what you should get if you lofted the above offsets. Click here to download the forms drawing. You will need Adobe Acrobat to read the file. While you may be able to print this file out full-size to get the drawings without lofting, I have not been able to do so myself. It prints nicely, just not full-sized. You might need a large format printer. You could also print it out small and scale up on a copier.

The forms start at the bow and work backwards. The center of buoyancy is just slightly in front of form 11. At form 18 the hull tapers in rapidly to make the characteristic truncated stern. I have not provided drawings for the cockpit, but any oval like shape will work. You will probably want the back of the cockpit about 14 to 16 inches behind the center of buoyancy. In the original the cockpit was a flat oval ring with the deck coming up to meet it. I did not copy this because it would be difficult to strip. Instead the cockpit is sloped down at the sides to match the slope of the deck.

I have not finalized any plans for the end treatment because they are kind of tricky and would have to be worked out in place. I would advise carving most of the bow out of a solid chunk of wood one to two inches thick.

The top picture is profile view of the last two feet of the stern and the lower picture is the first three feet of the bow. These are drawn out rather crudely, especially the bow but they are a rough approximation of the original. The Aleuts had a wide variety of treatments for how they finished of the end. Feel free to be a little creative. There is a Adobe Acrobat file available of this drawing. The gray lines above are spaced ever 1/4" out from the centerline and may be useful for creating a first approximation for a solid stem piece.

Note that the darker blue horizontal line represents the datum waterline. This where the boat will float at a 215 pound total displacement and as such the jaws would tend to catch a lot of weeds. You might want to change the shape to reduce this problem or scale the boat up so it floats higher.

Note also that these drawings represent the outer surface of the boat where the forms drawings are "corrected" for a 1/4" skin thickness and will thus be slightly smaller.

This is a top view of the stern and bow. The light blue lines correspond to the gray lines in the profile view above. Note that in the above drawing the stern tapers to a sharp edge. This is not practical and you will want to make it somewhat thicker. The stern shape here is different from the original, but might be a little easier to build (not to say it is easy).

I won't make any promises about this design. I have tried to be fairly faithful to the original design, just fairing it out here and there. But the information I had originally came from measurements of a boat that was badly damaged. The lines were taken by David Zimmerly and he did some fairing out in an effort to represent the lines of the original boat, which had to involve a certain amount of guess work. These drawings and offsets are one step farther removed, and as such may not be worth much. However, I think it is an interesting boat. It should be quite fast, track very straight, but you may find it very unstable. I suspect most people will want to scale the design slightly to serve their needs. I apologize for the sparseness of the information about the bow and stern shape, but what do you expect for nothing. Hopefully, I've provide enough to get the more adventurous builders started.

Although these drawings are intended for strip-built construction, they may be useful for other techniques as well.

These plans are provided free for those who want to use them. I reserve all rights to the drawings and the published offsets. Please do not reproduce any of the provided without my permission. Feel free to make whatever copies you need in order to build the boat. I would really appreciate any pictures of the finished product you would like to send me.

I have recently built a new strip built kayak loosely based on this design.

Have Fun!

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