Friday, March 22, 2013

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.




Tuesday, March 19, 2013


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.

Sunday, March 3, 2013

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.