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Flapdoodle Dinghy

  

Frequently Asked Questions
(well... asked at least once anyhow)

I have started a support group for those building or interested in the Flapdoodle HERE

Motor

Q  How big a motor can I put on the transom?

A I believe the Coast Guard and other regulatory agencies limit it to 2 horsepower for a boat this size. Modern 2 hp outboards run about 28 pounds (12.7kg) 

Q  Obviously, there is a waterproof fabric at the joints.  Is it exposed on the bottom where it could become damaged in beaching the boat or is it somewhat protected by what appears to be a centerline keel plan?

A  The seam for the most part resides in a groove for protection.  


Materials

Q  Would luan plywood work (the kind you can get at Home Depot or Lowe's) for construction or would one need to use marine plywood? 
A  I was half through the second Flapdoodle design when I found a sheet of luan [meranti] at Home Depot that is the best piece of plywood I have ever found of any species. I keep looking to see if they got more. Another sheet later from HD was so bad it was not usable for anything structural, yet it had a sticker from the manufacturer. The veneer was about 1/3 the thickness of the good sheet.   Look for a thick layer of the final outside veneer with the least fancy grain. IE, plain looking. Also, the good sheet tested 20% lighter! 

Voids:  Some voids are hidden inside and you do not know they are there until you cut the wood. I was not as concerned about voids since I discovered that I could squirt polyurethane glue into the void. It expands as it sets.


Q  Assuming that I opted to leave out the daggerboard trunk, what would the Flapdoodle weigh? 
A  It is not possible to tell you that, since plywood varies + or - 20% weight. But I can carry the folded part under one arm with all the options such as daggerboard box. Figure about 40# (18.1kg) for the folded part.


Q  In your opinion, could it be assembled and launched from the cockpit of a sailboat? 
A  This would depend on the sailboat of course, but it is very easy to assemble (a little more so than the Seahopper type).  My guess would be if you can launch any other type of dinghy, you can launch a Flapdoodle. Incidentally, the Flapdoodle assembles without any tools.


Length

Q What is the folded length of the boat?  Is it still 7' 11" or is it longer?
A  The Flapdoodle is longer when closed... about 8' 2".  This is due to the geometry changes between the open and closed positions.  If you lower the height of the foredeck and stem (not the height of the boat) the overall closed length is reduced. Since much of the fore part is out of the water in use,  you could start building the FD and when you get to the section where the front plate is installed, cut off say, 6". The bowplate would have to be wider of course, and so would the PVC front panel. Again, I had thought of all this during design, but keep in mind where the mast step, etc. would be if you did this.  Also, the skeg could be shortened if you do not intend a rudder.

Q  Can I add to the length of the Flapdoodle by splicing two feet (or more) onto a eight foot panel cut from a 4 x 8 sheet of plywood?
A  To make a very long and complex story short, the geometry is complex. Small, seemingly innocuous changes can make big differences in the overall design.

A 1/16" removed to improve the fit in one place may have dire effects elsewhere. To be honest, this is why the dinghy is 1/2" less in beam, and a bit shorter than the intended 8 feet in length... So many 1/16" cuts to get it right.

I found this out the hard way. The Flapdoodle design was worked out on a strongback with adjustable forms. I spent many weeks wrestling the panels around on the forms and making tiny changes while keeping the natural curve of the wood. There is more than just making a boat that folds because the bottom and chine angles have to be maintained (the entire length)in order to have a boat that handles and sails well.

[A strongback is an inflexible back bone that forms are mounted on in boat building]

Leeboard

Q  Can a leeboard be rigged instead in order to save weight?
A  Leaving the DB box out will save some weight of the disassembled boat and ease of building.  I plan to add a leeboard design later to the plans. But since this is a real dinghy when assembled, there is no reason any dinghy style leeboard would not work.  There are weight saving suggestions given as you go through the plans.

Q I have been told the leeboard must be located at the widest part of the boat. Is this so?
AThe reason this is said is because the leeboards must be parallel to the direction of travel.

Q Why is the daggerboard in front of the seat and not in/under it? My friends think it takes too much of the rare space in the boat.

A This would be my choice for maximum room (included in the plans) then use a leeboard. . I would use a lug sail with the mast partner at the edge of the foredeck. (plans have been updated and now include this).

The daggerboard is angled to the rear, partly for safety in case something is hit, but it is the classic shape and recommended angle for a sail dinghy. Plus, it solves the problem of "scooping water" when under power. Quite a shock to see lots of water gushing up from the daggerbox. If you KEPT the angle and put it under the seat it would be too far back for most sails.

Mast step

Q  A lady building a 'Doodle asked: To find the ideal position for the maststep, I am told, the emphasis of the body of the boat and the emphasis of the sail must be in the same position. Do you perhaps know, where a full equipped Flapdoodle has its emphasis?
A The choice of sail will determine where the mast will be located, and the location of the daggerboard should be over the center of force for the sail. This is the sail I would recommend for you since it is cheap, simple, and easy to use and maintain.  You might look over this page to give you an idea of how it works. [a sail is included in the plans now] 

miscellaneous 

Q Will you design a Hunky Dory as a companion to the Flapdoodle Dinghy?
A  No.

Q Was kostet das Boot, was kostet die Lieferung nach Österreich? 
     [What is the price for the boat and for transport to Austria?]
A Sorry. I do not manufacture boats.

q  Can I put my 84 pound (38kg) 1.5 horsepower motor on the Flapdoodle?
A  I doubt it.  Is it steam powered?

q  Is it possible to build the Flapdoodle in aluminum, changing what needs be changed?
A  Interesting question. Short answer is I don't know, but believe it possible. My only real concern would be sharp edges near the PVC fabric hinge, but with care even that would not be a problem.

The newer wood adhesives such as Probond II polyurethane work very well on aluminum. I have not priced sheet aluminum in quite a while, but it may be a good choice in view of rising marine plywood prices. An aluminum Flapdoodle with hardwood trim would be very beautiful indeed.