I totally agree with Brett and Lester.
You will forgive me, gentlemen, but almost every Footy design I have seen (apart from boats that are self-evidently toys) strikes me as an attempt to stuff a fairly ‘ordinary’, ‘nice’ little boat into this rather unlikely set of design parameters. Many of them succeed - ones that spring immediately to mind are Bobabout herself, Razor, Halfpint, Kittiwake …
There are, of course, perfectly legitomate reasons for this - some commercial, some to get the class going without frighening the punters off by ‘weird’ designs with unfamilar aesthetics, some because that’s the kind of boat the designer wanted to build and so on.
Most use fairly low-tech construction for ease of building or (and it is not quite the same thing) ‘dad and kids access’.
So where do we go from here? I remain totally unconvinced, as I argued above, that crude design is any less harmful at this size than it is at any other. The fact that the gains in drag are tiny in absolute terms is offest by the fact that the amount of power available to overcome that drag is also tiny - and the windshifts are just the same.
My calculated length of a Footy internet course differs from Brett’s slightly - he has added in a fudge factor and I have not, but we are broadly agreed that it is about 600 feet - 600 boats lengths. In an America’s Cup boat this is something in the order of 50,000 feet, so knocking on for 10 miles. Taken in those terms (literally) microscopic differences start to have an effect. (If these figures don’t seem to stack up, remember that hull speed is proportional to the square root of the waterline length - twice the length doesn’t give you twice the speed).
If anyone recalls, my first posting to this site was about ‘Chequebook Racing’. My contention was that hi-tech materials did not matter as far as costs were concerned because the abolute quantity of material involved was so small. This is partly true: minimum order quantities mean that setting up to build your first hi-tech Footy can be quite expensive - but you have an awful lot of material left over to build the next dozen!
Like Neil and others, I do not believe that the bot scout should be the ultimate litmus test of appropriateness of a construction technique. Like them, I also feel quite strongly that the use of high tech should not be viewed by anyone - dad, doting graandfather or (probably least likely) the boy scout himelf - as a bar to the boy scout. However, as design advances cost will become an issue.
In order to keep costs down and move forward away from the ‘toy’, we have to get our acts together as a group - and one of the areas in which this can be done is foils, hence the title of this thread. A persistent teenager with good eyesight, or a trained model maker like Neil may be able to make accurate foils. I cannot - and neither can most of us.
I am investigating whether it is possible to bring together two resources to which I have access (or at least a degree of contact) to see whether it is possible to make pulltruded carbon fins available at a reasonable price. I guess (and it is very much a guess) that the wholesale price of the pulltrusion is likely to be around USD 25/metre if the die can be be made at little or no visible cost. On the basis that Reynolds numbers are not dissimilar to those used by model sailplanes we would use a section that is conservative in that type of application. One thiing that is encouraging here is that comparability between compressible (air) and incompressible (water) fluids improves as the Mach number goes down - and the Mach numbers of Footies and sailplanes are both tiny.
I have no interest in making any money out of this. Neither have any desire to upstage Brett’s investment in fluid dynamics know-how. On that basis, is anyone potentially interested?
OR, EQUALLY IMPORTANT, DOES ANYONE THINK IT SHOULDN’T BE DONE? - UNWANTED HI-TECH, TENDENCY TO FREEZE DESIGN ???