The Magpie  by J.P. Sullivan

Since I am building a boat with compounded  curves I added a laser to my strongback. This has revealed mistakes on so many occasions already. As the project has moved forward I found myself reverting back to the old string method which is so much simpler yet gets the job done. Keeping the curves fair and accurate is turning out to be a real challenge . I now see why most everyone else chooses symmetry.



      
                     ROCKER                                                                 

Just trying to get the whole thing in the picture. The person gives  some perspective to the shot.
       


Above shows the Banana Factor . 2 inches of sideways bend in the keel. This is hard to show as it is so subtle and I think the photo ends up just showing the rocker.

        
  A look at the bulkheads gives my idea as to the shape of the hull.

Below shows the rabbet to receive the gar boards.
 




 
Here the main bulkhead can be seen straight on. I  have opted for less sectional asymmetry due to the fact that I am using
the sideways (oblique ) curve in the keel ( very obvious here). The first of the two gar boards are seen in place here ( leeward).
As well the fairing strings can be seen. These help me keep the curves of the asymmetry fair and level. The string has ended up being the superior method of keeping things fair compared to the laser .




  
A closer look at the bulkheads and gar boards. The gunwales will be laminated to a dimension twice this size hence the extra large cut aways in the bulkhead. The curvature in the keel combined with the sectional asymmetry make for an almost flat lee gar board. This worries me some as I feel it will cause the boat to turn to much to leeward.







 
Here the extreme asymmetry can be seen due to the combined sectional asymmetry and the oblique curvature of the keel.
At the deck area you can see where I am building a traveler to carry the sail from one end to the other. The leeward gun whale can be seen on the very right of the traveler , showing how flat the lee side has become.



Since I need to install the remaining bulkheads I had to come up with a plan to go by as far as the joinery goes so I threw this together to give a look at The view from above. This is how I see the boat upon completion. The squares are 1 sq. foot roughly



The spars are made out of box construction to keep them as light as possible  . It was traditional to keep birds in mind when making your boat so I went with the hollow bones idea.  The boxes are very light and will be wrapped inside and out with carbon fiber when completed. in order to get a nice wing shape. I compounded the curve so that there is more curvature by the hinge than at the ends .
This was strictly a decision of appearance

                   

The snow helped get a look at the spars from a distance . This is about the size of the sail as I see it (at this point)

 I had to dig a space for the strip planks to leave the building out an opening through the snow drift as my shop is not long enough . More pix tomorrow.



    


The Iakos

The main  structure holding the outrigger .
I wanted to steam bend this wood so as to not store energy in the laminations .
What a pain in the ass that was but I am very happy with the look as well as knowing it is done right.
 






To steam bend the wood i built a simple box that slid over the members . using the main (heavy Iako members to bend the wood over.
A very primitive yet effective solution





THE AMA

The Ama is by far the easiest part up until this point.
I am going with a fairly heavy one as I think that the Ama should stay as close to the water as possible and at my age if it never comes out at all i am good with that.
After studying some of the very old pictures on the net it looks like the traditional craft used very heavy looking wet logs with neutral buoyancy so i think mine will be just fine. As i said it is quite easy to make another should i need to modify it.
I have developed an odd method for bending wood in order to remove stress inside the laminations. I could have just cut the wood up into strips and then glued them into the compound curves that I needed but instead I have started using this system I call Solar Steaming  that cuts the amount of work down dramatically. I used this Solar Steaming to make the Ama For Magpie as follows.

Magpies Ama 

   1    12 foot 2x8
   1    12 foot 2x6
   2    12 foot 2x4's
All spruce,        total cost around thirty dollars Canadian

7:00 am    Trim all of the 2 inch edges on the stock so they are all true and square. Clearly mark the centers of each board  (6 ft. mark).
7:10 am    Set the table saw to 45  degrees and cut two triangles from each of the long edges of the 2x12.  Put  these aside for corner   
                 blocks later on. (The board should now be a trapezoid in section)
                Set the blade 1/3 of an inch proud of the table surface. Place the 2x12 on it's large surface down and cut a trough 1 1/2 inches   
                wide  and 1/3 in deep by passing it repeatedly over the saw blade each time moving the fence 1/8 of an inch.
7:35 am    Using an old scrap of six foot oak straight stock , mark your rocker one the 2x6,   I only put 2 inches of rocker over the whole   
                12 foot length .

 Using a jig saw cut the rocker out of one side of the 2x6 . Keep the cut aways for later. Be   
                sure  to take time to make this cut as smooth as possible as it will save work later..
                Dry clamp the 2x4's onto the sides and mark the bottom where you want the sides to be and the cut the excess away from the 
                bottom.

The stock should look like this:


8:10  Using two pipe clamps , torque the 2x12 over the rocker cut into the 2x6 and drill pilot holes every eight inches along the length of the T joint and put in some fat assed   #14   2, 1/2 inch screws to hold it in place, (use a smaller pilot hole than normal and double up the screws to every four inches at the very ends)


Drill 1 inch holes where the small Iako members will pass through the"now"  main beam of the Ama.
setting the jigsaw to 45 degrees makes short work of this job. (above)



"Very gentle rocker"

Dry fit the Ama onto the Iako grid to make sure the angles are correct as having to fix it later will redefine pain in the ass for you

The support strut holding up the main  beams is  just a  temp. scrap of wood . The actual  strut is not made yet


Solar Steam Bending
Start by placing blocks to accentuate where you want the curves. If you want to bend your wood two inches use four inch blocks.
Over bending is how to make things fit like a glove. Pour hot water all over the Ama parts and give it a good soaking.
I wrap rope around the project to keep the plastic off of the wood so that the hot air can circulate.
  




Wrap black plastic garbage bags tightly around the project and duct tape tightly shut
    




Then wrap a single sheet of poly over the whole thing to create a second layer of insulation.
Angle the project north and south and have it ready to go first thing in the day. in 30 degree heat and clear skies the ama will heat up to be very hot, not unlike a black car seat
 



when you see the condensation (above right) or when the sun starts to weaken add the clamps to the areas that the most bend is required.
You have to feel with your hands to make sure that the 2x4's are clamped all the way down.

I let it sit clamped until the sun is gone and then pull the plastic off . You can see how perfectly the boards now mate together with no clamping (below right) .








The cut aways from the rocker  are reversed and epoxied to the top ends of the main beam this will give a excentuated curvy look and will help narrow the bow decks of the ama helping it to escape the water after entry. This step is done after the steaming to avoid exposing epoxied joints to the heat.


My hope is to launch this boat on my birthday in Late August.


The Garboards
Well So much for that pipe dream  Here it is The end of November  and I have hardly done a thing  since the Ama.

The Garboards are scarf joined and trimmed to fit like jigsaw puzzle pieces.
I wanted to increase the amount of buoyancy in the bows to keep the boat from being too unruly. By adding some buoyancy to the bows , This should help keep the boat from hobby horsing too much . Technically this is called Pitching and apart from making people sick it is also detrimental to speed.
With the garboards in place , I simply hung bar clamps along the edge of the garboard until I t achieved that classic " Artillery shell " shape instead of looking like the ends of the inside of an envelope.
It was also my desire to try and get the immediate entry point of the boat to  be symmetrical  and then as the water passes over the hull to impart the asymmetry of the hull after the break of the bow.


With the clamps holding the garboards in the shape I wanted,   I epoxied  Kevlar/Carbon Fiber fillets along the length of the keel to keep them in that shape. This is very similar to the tortured plywood method of laying in a keel fillet.


Below:
The resulting torture actually takes very little pressure to do . The beam at this point looks wider than it really is . The beam at this point is only eleven inches over 27 feet.

 

Below:  The picture below is  another optical illusion , the bulkhead is actually thirteen and a half feet from the stem .
It somehow only looks like half the distance. This last photo shows nicely how I am getting some of the desired buoyancy into the bows.