This is very interesting. 
So, is it a matter of displacement to ballast ratio high, whilst keeping the overall displacement light, to run more sail, and to see which is the
muscly-est. 
gotta few concoctions to try. One with a ratio in the 70’s for sure. 
Weight results are posted in the “Regatta in Raleigh” thread. I though it best to keep it together.
As the coiner of the phrase ‘American Muscle Footy’, can I have my two-pennyworth?
There is no vey tight definition. The phrase is by analogy with the American Muscle Car, so I suppose more of the things that make you go fast (stability, sail area) and more of the things that slow you down (weight, form drag). Think of a Mustang Boss.
The alternative (?) has yet to be named but it goes in the opposite - little stability, little sail area, little weight, little form drag. Consider a Caterham 7 or Alfa-Romeo 1750 Duetto, both of which are competitive with the American car down a windy road.
Long, light and narrow you say Angus??
Heres a little free sailer that I have been testing…the next one will be r/c.
LOA…330mm
Draft…not as much as you might think??
Beam…bugger all…40mm?
SA…havn’t mearsured it…but is high aspect ratio.
This is a mini Marblehead really.
will be a challenge to get a respectable ballast ratio with this displacment-250grams all up!!
This thing flys!! and I belive it to be the future of this class.
In more ways than one - I gather from Sandra that this is the first time your kids have shown much interest in designing a Footy - 'cos this one is kewl. Rather confirms my suspicion that many of those who profess to know about Footys for kids also give them white Y-fronts and sensible woollen socks for Xmas.
Hi Angus,yes 40mm foam was all we had…so 40mm beam it was!!
It is true I am afraid…I am not the only mad yacht designer in this household now.
Now if only I can master this blasted new fangled camera!!
I hesitate to talk on front of the grown-ups
Pic attached of my 40mm beam footy attached - with Razor for scale - does this qualify for the lean-and-mean brigade?
that looks cool may have to try one of those myself
Brett! i thought you blurred the photo out so nobody could see your super-secret design!:devil3:
Nigel … I believe that challenge is to design and build a 300 gram boat with 200 gms ballast … maximize length at the waterline (330+ mm) … minimize wetted surface (ummm … hate to say it the context of this thread, but designing narrower helps) … build bouyancy into the ends (ummm … narrower again, damn) … maximize sail carrying ability (wider) …
Brett … given that batteries, electronics measure at minimum 80 gram (+ hull rig appendages at another 25g or so) I can’t see, short of a rule change, how you’re going to turn your freesailer into a footy that achieves the same performance as the freesailer … that said, I respect your expertise and am assuming that even thought she’ll be a different boat you’re of the opinion that 115g ballast is enough to support whatever SA is req’d to drive her (I ask in context of my boats that have very limited wind range effectiveness with 125g ballast and a wider platform to support it) … curious if it can be as simple as a radically more slippier hullform …
Really you think I would do that?? LOL
Not quite…along with lighter displacment come other benifits…less strain on servos etc so now they can be lighter. A trick new way to control the sail with a tiny servo…A 1 gram RX also.total mass of electronics and boat can be less than 90grams(substantial loss of surface area in the hull and new build materials.lighter, refined McRig)…leaves a respectable chunk left for ballast.(160g)
I thought you guys wanted to change the battery rules anyway?? if you do (And for what its worth I don’t think you should) be prepared for what will happen…the reward will go to the best builders not the average guy as has been suggested.
And the dsign process becomes more involved and precise. That one is a lash-up of Brett’s, but it’s the result of 6-months of very frequent phone calls. If the lines of the final ‘production’ boat are mine, they’re going to take a ln time to draw because of the precision required by the shape (I don’t mean fairness - Brett and a piece of sandpaper can soon take care of that - more how all the numbers stack up against one another). We’re also going to have to calculate righting moment and trimming moments properly. The number of permutations of beam, balast, draft, sail area, AR that are ‘just wrong’, almost certainly makes sme sort of mathematical optimisation of the ‘sweet’ zone worthwhile.
I guess that this boat is not far off being as far as you can go down that road, using home tools, freeware and, a spreadheet and commonly available , easily understood (i.e. not designed for professional engineers) books on yachts and naval architecture.
Of course, it may be the wrong road. Hence the proposed Livrpool Seminar.
Yes indeed Brett, I do hope that those who will vote yes to a battery change do realise what the consequences can be. The widenning of the gap between those who have the knowledge and skills to build super light and the average-to-good model builder trying his best. The battery rule (4xAA) does keep the super light end in check. Having personally handled Moonshadow she is a lovely piece of work Brett and shows just how far you can go even with the battery rule as it stands. If she were to prove to be ‘required equipment’ then I think I can get there with practice and great care and I think others can too, but there won’t be any cheap kits of them I am sure. While the battery weight keeps things in check I do believe that any of the currently popular designs if well tuned and well sailed can win any random regatta.
Long may that continue.
Graham
I’m with Graham and his comments on how high tech and light weight might make our fat, low tech but surprisingly tough and very fun Footy’s obselete. I for one would not be happy at losing the constraints that the 4 AA batteries have as an INTENDED leveller of the various designs. But let’s face it, though there aren’t many regatta results in the books, we have yet to see a lightweight boat survive a regatta, let alone win one. So I’m putting my quaking at the ‘light boat threat’ on hold until that happens.
i must side with the “pro 4AAers” as well. that portion of the rule, while it definitely limits the final performance envelope of all footys is one of the class’s defining features, and more over, makes it viable to build inexpensive, and easily maintainable boats.
it seems to me that the battery rule is one that if removed would so change the face of the footy that in good conscience, the class itself might well need to be renamed after such a change.
I wish I could entirely agree with you. Moonshadow is a Pandora’s box, which should perhaps never have been opened - but it has. Exactlly the same principles apply to the Muscle Footy. In very round terms, using the standards of construction as Moonshadow you could be talking about a 600 g boat with a bulb of some 450 g. That’s a 75% ballast ratio! I can think of some very good reasons why such a boat might not work - but it might!
Incidentally, before anyone accuses me of taking things on a completely inappropriate level. Next year I am going to be realistic about my talents as a driver and the effect of the pain killers on my concentration. Moonshadow will be lent to Mike van den Peet, a very talented newby living in London. This is not a commercial ‘hired-gun’. I shall probably buy one suit of professionaly made sails for comparison. If we want to change bulbs, I shall probably buy Richardson-designed bulbs from Andrew Halstead for the sake of convenience. The only big money involved is that I would like the boat to go to Sheboygan in May. I cannot go myself, so I intend to make a contribution to Mike’s airfare.
After the March Hare in Colwyn Bay at the end of March, we will be freezing he design of a new boat, provisionally Voortrekker. Launch of Voortrekker is scheduled for late May with comparative working up against Moonshadow. The front-line boat thereafter will be whichever is more successful.
If the ‘I just want a simple boat for fun’ brigade cannot stomach this, I will be rather sad. I believe that you should try to do things well. This is not cheque book racing - the trip to Sheboygan is to have a British Footy race on the USA, not an attempt to carry off the trophy (althiugh we’ll try to do that too!). What it is is well-organised racing. Anyone can do it. If they take the trouble to do so, they probably ought to do well - and people should not resent the fact.
Just to clarify because I know it is all too easy to read what you think someone said rather than what they actually did say…
I think Moonshadow is a lovely boat and a credit to Brett’s skills, as a broader boat designer I have no fear of it or it’s ilk. I am very happy that it exists Angus and do look forward to racing against her one day.
Without a doubt Angus is correct in saying that a heavier footy will benefit from lighter construction just as a lightweight will. Note that Siren was the lightest boat at the Raleigh Regatta. Siren can easily be lighter than that by simply exchanging materials. Bill has made a point of building a lightweight hull with basic techniques too recently, so I think the kitchen table modeller is still well in the hunt.
But the defining point is that lightweight or heavy, the 4xAA battery is a larger proportion of the finished article than 4xAAA would be. That makes the last few grams which take the maximum skill to remove so much more important, and possibly too important,whether you are building a 20oz or a 10oz boat. Please don’t think that 4xAAA will only make ‘your’ boat lighter and more efficient, belive me, the best builders will make the best use of it and the average builder will probably fall further behind.
Graham
I’m definitely with those who want to retain the 4AA rule, for all the reasons so well stated.
By the way, construction proceeds on my Liverpool challenger. It is using the basic, but lightweight, construction methods Graham mentioned. Scott Spacie is building some nice McRigs for me, so I guess we represent a team challenge.
Since the water is hard here, its first sail will be at Paul’s regatta at the end of February. I’ll use the club racing on Saturday to get the kinks out and hopefully be in racing trim for Sunday.
I’ve decided to forego my usual swordlike names for this event. Since we represent the “muscle Footy” group, I’m naming the boat after my favorite muscle car. The boat is christened “Cobra” and its appropriate sail number is USA 427.
Maybe I’ll paint it with a nice racing stripe down the middle.
Happy Holidays…Bill H
Post pics of “Cobra” when she’s done.