Matthew, the reason the displacement varies is that I used the same LOA, draft, max beam, and transom beam measurements. Given those restrictions, the chine hull has “corners” included in the displacement, where those corners are rounded off and therefore eliminated from the displacement of the round-hull version.
I revised the chine hull to get equal displacement by varying the draft, and compared again. As you would expect, the wetted surface and drag numbers for the chine hull were reduced a bit. Wetted surface was still lower for the round hull, but drag was still lower for the chine hull.
I’m guessing that drag calculations for such small boat at such low speed probably don’t mean much, though. So, I still think either design can compete on a relatively equal footing. [^]
This is the second footy from the Halfpint mold, so the hull is the same, but the raised foredeck and curved fin gives her a bit of a different look. Fin/bulb weight is 8 ounces, ready-to-sail weight will be 18 ounces. Building these little things is fun!
I like the ‘fit in a box’ rule. Simple and quick. That would allow anything you feel - and the hull design would determine the fastest boat. I, too, after reading the rules I found (which was like a year ago AND allowed overhanging rudders) felt that catboats would be ideal. Make it a monohull that (or maybe not!) fits in a box. These are supposed to be low-cost, low-emotional-content boats anyway. I can think of much worse things to do than sitting around an inground pool, liberally imbibing your beverage of choice and racing these things, eh? Criminy - you could help your boat by waving a T-shirt at it! Or somebody’s T-shirt
There is nothing - absolutely nothing - half so much worth doing as simply messing about in boats. Kenneth Graeme, Wind in the Willows.
I have just finished my footy hull, is is made from 1/32" basswood, and will have no glass exterior and just polyunithaned or epoxied finish. I will be using water color paint to stain the wood before water proofing it.
The hull weight comes out to 1.5oz with the supports and all up weight should be around 16oz.
I will be using the hs 311 for the sails and hs-81 for the rudder, I know it won’t be to the rules but until it becomes a AMYA yacht it really doesn’t matter. I am using a 6oz fishing weight for the bulb and a wood dowel for the mast.
Many ppl are using micro servos in the footys…not sure it is a good idea to limit the use of them,prices have come way down and you can certainly build a better sailing model by using them.
One guy here has built a nice tri with micro servos…goes pretty good to,not that I am advocating that multis should be allowed,maybe a seperate class for them.
I have an idea for a designing/building comp for footys…anyone interested?
you design and build your boat …post the pics here with a brief discription
We could have a 3 month timeframe for the comp. I will give away some kits etc as prizes.
I thought it might be a good way to stimulate growth.
If anyone is interesetd then I will post some comp rules etc and start a new thread for entries.
I was thinking along the lines of general design exellence/quality of build or any other appealing features. Don’t want to make it an arms race.
eg super light RXs are avalible that weigh less than 1 gram…use actuaters instead of servos/li po batteries etc…Ive seen pics of planes that weigh 2.5 grams with 3 channel radios.
cheers
Brett
Brett have you or anyone else found that you can use an HS-81 for the sail arm servo on a footy? the torque is 42 inch ounces, what do yal think or just stick with the hs-311.
I have tried a cheap knock off 9 gram servo I bought on e bay.
I am guessing the Ho Tech would be similar or better
has enough power,better when i added an elastic band to help it pull the sail in.The servo works against the elastic when letting the sail out.works a treat.
The GWS pico servos look interesting,5.4 grams each,and resonably priced.
Brett
Brett, I’m all for the comp…as you know, I’d like to encourage footys (footies?) here in the States, and your idea sounds like fun. Maybe we could make it a condition that the winners share their designs with everyone? The free access to different plans might motivate some builers who haven’t given these cuties a try.
I guess we’ll have to pin down a set of rules, too. I know it’s tough to come to consensus, but establishing a recognized racing class for these will require some consistency. I hope we can arrive at a fairly simple set that allows some flexibility for innovation without requiring high investment costs. Your original concept was sound, but others have contributed good ideas, too.
On another topic…I find this forum a bit more difficult to use than a couple others I participate with that are Yahoo groups. Is it just me, or should we consider moving to a place with greater visibility and ease of use?
Vince, your footy looks good! Keep the pics coming. I’m especially interested in creative ideas for adapting things like fishing weights for bulbs.
Rick, any pics of your boats sailing against Rob Amaral’s? Please encourage him to post pics here, too.
I don’t have any pictures of Rob & my Footies racing. These little boats keep you very busy at the controls, not much to snap pictures. I’ll see if I can get a camera out there next time. Rob and I agree these boats have a very high Cute factor.
The ballast I have on these boats is 5.5 and 6.5 oz. I am experimenting with some different rudder designs right now. The material for the white rudder is Depron.
I have attached a picture of an A3 with my “Right” footy, and a picutre of my “Left” footy on the bench.
Wow, Rick…that’s a different rudder design, all right. Rob told me you guys are thinking that these little boats work best with big rudders. Let us know what works. Anybody else have experiences with with big rudders? I mean, does size really matter???
I have found a tendency for my footy to drift off in light air. On my first footy I had a rudder 35x75mm. My second boat had a rudder 53x100mm. The new foam rudder is 63x150 and a different shape.
I’m curious to see if I get some lift from the foam. It it works in test I will probably add some fiberglass.
What fun.
Rick
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Fairwind Web site: http://Fairwind900.Home.Comcast.Net/
Rick,
I noticed on some photos that you had posted that you had set your boat up with a swing rig,the rig I show on the plans would be best termed a shroudless rig.
the forward boom under the jib boom is just there to anchor the jib pivot and something for the jib fairlead to sit on.The idea being to be able to remove the whole rig easily incl sheets without any fittings on the hull whatsoever.
The swing rig you have setup may be what is effecting your balance.
letting the jib out a little in relation to the mainsail may help your balance in light air also.
You must be slower in light airs with thhose big rudders,your surface area is much more than before.
I would look to solutions with the rig before the rudder.
Your boats look cool though,well done.
lets hope plenty of others build up some footys.
Thinking on rules etc for our comp.
Not sure if it should be here or be done elsewhere on the web…
Cheers
Brett
A3withspare.JPG
DepronRudder.JPG