I laid out the keel pattern on 1/2" ply sheet, the centerline board on which to build the casting plug.  I traced each cross section from the plan (Keel & rudder - lines & templates schematic 97/2) and my trusty helper cut them out.  I pasted them on wood panels and cut those to size.  I will build that up into a 3d structure then fill with polystyrene.  Epoxy and glass will go over that after some fine shaping and bondo work...at least that is the plan.

This is the essence of the F-15, at least from my narrow view 5,000 miles from the nearest regatta.

I finished the keel proposal and request  and submitted it to a casting business in southern California. No word yet but it is a one off strange request.  They did a very fast turn around keel some years back for a damaged boat and they pour in the several ton range daily.

General specification:

Keel Plug:

1. Construction: Plug is to be one part.  Will discuss with you if it needs to be two pieces.
2. Material:  Built up from wood, foam, Bondo and fiberglass.  See figure 1.
3. Shrinkage allowance: 1/8”/foot shrinkage allowance.  
4. Draft allowance:  The shape seems to be well accommodating for retrieval from sand form.  
5. Finish:  Sanded fiberglass.
6. Weight:  Approximately ~30 lbs.
   Shipping dimensions: 2.5’ x 1’ x 7’
   Metal Keel Casting:

1. Construction:  Malleable cast iron.  
2. Material:  Malleable cast iron, Nodular iron both appear to be good toughness without post heat treat.  
3. Finish:  Smooth as possible without incurring additional cost.  
4. Weight:  Expected 370 lbs.
5. CG:  29.5” horizontal, 6” vertical, center-line transverse.  
6. Flange:  I am planning on ½” diameter through holes, 10x eq spc.
7. Shipping method:  TBD - ocean freight.
8. Shipping weight: 400lbs
9. Shipping dimensions: 2.5’ x 1’ x 7’

   

Figure 1:  Plywood sheets, foam and fiberglass plug with same dimensions as finished piece with compensation for shrinkage.

I am putting this log in place to maybe gain input from others.  The plan, emphasize 'plan' is to build a flying fifteen keelboat.  I aquired the plans from England some time back and only now see the window that I might build.  This will be done in coldmolded style. 

I generated a list of all materials, steps and time with costs.  I would like to keep the cost in the 5-7k region for everything.  I hit some obvious road blocks:

Keel:   The first is the keel itself.  This organic shape of 370 lbs of cast iron is outside what I would consider casting with a backyard furnace...oh sorry, Blast furnace.  I made a request to Pin&Bax in UK but no quote has arrived.  The shipping cost might wipe me out anyway.  I am considering a non class keel that matches the horrific 3-500 ft-lb moment arm this thing puts on a hull.  A stack of steel plates torch cut to the shape then sealed in resin....well we'll see, working on that design for now.

Sails:  My living room and dining room just happen to be perfect size for a temporary loft.  And that Kenmore sewing machine I found at the dump actually rams through 6 pairs of levi material.  I am sweet talking the family for that one.  Otherwise a sail set is 1800.00.

Mast:  Need to figure this one out.  I would be game for a wooden mast.

Trailer:  I plan to modify and existing trailer in the future that will do teh trick.  It look necesary to have a trailer that can be backed in to the water with a long rope or chain as it really needs to go in farther than normal.  Our local launch also has a bridge to pass under so rigging will be after that.