Transat 6.5 as Footy

Footy Class General Discussion (Footy)
21

Gosport is the only worthy results we have so far :slight_smile:

I don’t see “Moonshadow” as impractical for real racing…give me a week with her and I would be confident to race anybody.
I have designed and built a lot of Footys…after 6 years “MoonShadow” is the direction I would be heading.
Comparisons between open 60s and ACC yachts are crazy…both to totally different rules…as are footys…and don’t forget the Cube law either.these are little models not ocean racers.

Show me any class…model or fullsize where lighter displacment and larger ballast ratios have not improved performance?? anyone…any class ever???
Didn’t think so.

A 200g tri will prob beat them all anyway…

22

Brett!! It’s not a crazy comparison at all … one is faster than the other … why? And cube law doesn’t change physics … boats with equal righting moment will have exactly the same sail carrying capacity regardless of displacement … and nope I can’t show you a class, but then there is no other class where a 10% increase in LOA amounts to near zero difference in theoretical hull speed, nor is there one where a 25% difference in displacement amounts to only 100 grams and zero difference in the waterline, and potential zero difference in heeled whetted surface …

And besides, I agree with you … and your ratio is damn good …

23

I think that a broad statement like, “Gosport is the only worthy results we have so far”, overlooks one factor that is not getting much airplay here. The pursuit of lightweight boats is admirable but at a certain point they become too fragile for fleet racing (and the inevitable collisions) or challenging conditions such as those at the New Hampshire race or Angus’ damp gathering. Remember, in order to win a regatta you need to finish the regatta.

I might also add this into the mix. With all the advances in materials and radio technology the M Class, the pinnacle of model boat development, has stabilized at around 11 pounds displacement. In the early '90’s I designed an 8 pound boat and a 9 pound boat. Both were very fast downwind performers. The lighter hull was competitive upwind in lighter air but as the breeze freshened she couldn’t point as high as the heavier competition and tacking had to be executed well or she would lose too many boat lengths in the process.

In a fleet race you sail most of the distance around the course upwind. Upwind sailing requires some displacement to carry the boat through tacks. Upwind sailing is where fleet racing tactics come into play. On the runs and reaching legs its all out boatspeed in a follow-the-leader chase. Upwind work is where the most lead changes happen, and where sometimes you can find a shift all your own and enjoy a huge gain.

So all of you post perusers out there who look at the displacement-to-ballast numbers that have been shown here while sitting in front of your gram scale scratching your head and wondering if these guys use the same gram definition that you do, need not be too concerned that your boat is hopelessly heavy at this point. Wait until this all shakes out, until there is enough varied race data to make a conclusion about how light your next boat should be. Don’t discount those heavy air results, they tell you something as well.

24

You can always trust the topic of boat displacement to get folks excited!

I’m a bit concerned that people might get the idea that highly sophisticated building techniques are needed to build a light boat. So I built a hull yesterday afternoon. Primary building materials/tools included 1/32" balsa, a scissors, masking tape, and superglue.

I had my local Post Office guy weigh it this morning. The scale is accurate to 1/10 of an ounce. The hull as pictured weighs 4/10 oz. which converts to 11.2 grams. Of course it will weigh more when the keel trunk, rudder support, etc go in. But it will still be very light and a lot easier to build than most of the alternatives.

My original Razor was built the same way. It’s been repaired after a couple collisions with big boats, and I’ve rebuilt the keel trunk/mast box a couple times to try new ideas…but she’s survived 3 or so years to date.

So high-tech is not required. You can build a light boat on the kitchen table…unless, of course, you think a chine hull can’t win races! :wink:

Have fun with Footys…Bill H

25

Hey Bill, that hull looks familiar. That’s the Widechine, aka FatBob design, right? Mine came out to 26g with reinforced joints and a polyurethane coating for strength. I don’t have a total weight in my head but could weigh it when I get home.

It sails pretty good. I’m racing it in the regatta and there should be at least 1 Razor entered too.

26

So whats a lightweight footy???
length/displacment ratios are the most common way of comparing boats of different lengths.
If a footy was built with the same L/displ ratio of an IOM for example it would weigh 148grams.
Moon Shadow weighs more than twice that…she is very heavy indeed.
A US1 meter is nearly half the weight of an IOM so I have not picked an outragous example.

Just because many of the boats built to date are greater than 500g displ does not mean that all footys should be so.
My first boats only came out to approx that weight because of he servos and batteries used together without any real weight saving construction methods.
My motive was just to sail a 12 inch r/c yacht…not design a world beater

I have free sailed 3 footys…one at 200g one at 350g and one at 500g.
The light one always gets to the other bank first.

I also belive that many of the downwind handling problems that Footys are prone for would disappear with lighter displacment.

27

If thats the case then lets ditch the AA battery rule and help average builders approach the displacement numbers that the pros are posting.

4.8 AAA NiMh packs are 40 to 50 grams lighter than the average AA pack, and the price difference is $4 to $6 more for the AAA pack. The grams savings takes your one pound boat and turns it into a 410 gram boat and improves the displacement/ballast ratio to boot.

28

One other thought, the displacement numbers under 400 gms along with the displacement/ballast ratios listed are pretty hard for the average builder to match. Are we already at the point where homebuilding is being discouraged?

Bill’s multi-chine project is starting out pretty light. Will it stay that way once all the reinforcing is in place? Will it survive being T-boned by a newbe with a “heavy” Footy? Many of the lightest boats are more likely suited for solo timed runs on the Internet course and would probably not survive fleet traffic or heavy winds. Wait haven’t we heard about that already a couple of times? Building light is great, building tough is smart.

29

just though i’d join in on the light-weight/strength part.
my first Laja, was just unger 400gm, and my next ones(keeled) have been refined a lot lighter, and i tell you, they won’t be damaged from collisions.
paint might get mared;)

30

Now that we are no longer in the same country and therefore have normal telephone communication, my very dear friend Graham McAllister tells me that my report of the Slithey Tove in Llandudno fails to bring out correctly what a triumph it was for the Footy class. He is, of course, right.

There was a casualty rate. Every casualty failed through lack of preparation, mostly loss of watertight integrity through use of the same awful tape. This had nothing to do with the seaworthiness of Footys and everything to do with the inexperience/incompetence of their owners (including me).

What was impressive was that the boats that were properly prepared (three of them medium displacement, medium sail area designs, one a heavyweight – and all from well-known designers) sailed extremely well in much more wind than could reasonably expected. In around 15-16 knots windspeed (7.5-8 m/s) the two McAllister designed boats were undoubtedly overpowered with their ‘off the standard sailplan’ A rigs, but they were consistently romping away from the Stollery and Hagerup boats. Of course there were other reasons – possibly better sailing, better sails and all the other things – but it is difficult to believe that the two ‘tail-end Charlies’ were not underpowered. One factor in this might be the atmospheric conditions. Despite the inevitably high level of wind chill, it was quite a warm day. From memory, barometric pressure was forecast to be 1006 mb (no, I am not going to convert that into Halliburtons or whatever you Americans use) and maximum diurnal temperature 73° F (the Fahrenheit temp happens to have stuck in my mind!). Since the weather did exactly what the Met. Office said it was going to do in every other respect, it is pretty likely these numbers are real.

Even so, it is impressive. At what I guess to be 20 knots life was getting very wild for he McAllister boats – still with A rigs – but they were still sailing and under enough control to get round the course. When the wind rose to 25 knots plus, I suspect we could have continued racing – but it was cold and wet so we called it a day.

Even more impressively, nothing broke. Apart from sticky tape, the only gear failure on any boat that passed the first hurdle was a crack in MoonShadow’s 3mm carbon tube mast. This was entirely the result of a sloppy piece of detail design on my part and there is no reason to believe it will ever happen again. Once again, all the boats concerned were the products of conscientious and thoughtful builders.

The results from Llandudno probably do not tell as a lot about what design is fastest. What they do tell us is that Footys are much more able seaboats and much better able to stand up to their canvas than has ever generally been thought. It would be very interesting to know exactly what happened in Laconia, especially since the two highly successful McAllister boats were (presumably) designed with the shores of Lake Michigan in mind.

31

The 6.5m is a fascinating class, but I feel it has little relevance to us. Apart from showing what can happen to a rule for cheep racing boats?
It will be very hard to make a scale 6.5m - Footy work -I would not say it’s impossible, but I’m thinking it…

When you scale boats down, the displacement falls with the cube root of the scale but the stability falls with the 4th root (displacement x beam) and the wind speed scales with the square root of the scale.

So a 6.5m scale footy will have a displacement of 110gms or less and a sail area, around 930 sq cm or more.
A good breeze of 15 kts for a 6.5m boat scales to only 3.2 kts for a Footy.
A Footy sailing in 15kts of wind, would scale back to a 6.5m sailing in 70kts, a good breeze for us, but survival conditions for them.

Boats with moving ballast are a different type of design to fixed ballast boats and both types need different hull forms. You can interchange hull types but it will be a lot less than ideal.
I built a string of wide- transom hulls for an off-wind race series and have spent a long time regretting it. They are fast at times but hard to sail well, the new narrow and light boats are faster- even down wind.

If you want a scale 6.5 boat or similar you will be much better off building a larger model with the movable ballast of the original. If you want a scale Footy, you need to start with a heavy boat - a motor/sailer, fishing boat or the like.
I quite fancy a medieval trading vessel, such as John Cabot’s ‘Matthew’ - 64 ft on deck and 85 tons displacement. This gives a 330gm Footy with 90mm beam with well rounded sections, sounds familiar?

Ballast ratio.
A high ballast ratio is always important. The previous example uses two boats with the same ballast and draft, but having 350 and 450gm displacement. The point is made that both boats have the same stability, so ballast ratio is not important.
But this means that both boats can carry the same rig in the same wind speed, so the lighter one has a much higher power to weight ratio and less drag, which makes it the faster boat.
Racers spend a fortune trying to get the weight down - one 6.5m sailor was planning to live on cereal bars and water, in order to save weight and improve his ballast ratio.

I didn’t mean this to sound be so negative, but Footys are an extreme class and I feel it’s best to start with a blank sheet of paper, rather than trying to adapt another style of boat to fit.

32

i’d only use the minis for style, not a direct scaled-down vessel.
as you mentioned the numbers don’t work.

(where have i heard that before?):rolleyes:

all i’d do is put a scale looking deck on my existing footy-class hull, coupla rudders, and maybe an action figure (lego-man or something).
do a scale paintjob of my favourite, and voila “micro-transat”.:smiley:

33

I agree, Ian.

And on the wide boats - they’re all rule driven, either diretly or by the legality of moveable ballast. If you are looking at real hull efficiency, you are looking at ultr-narrow, ultra-light displacement boats, aka multihulls.

And while we’re at it, can anyone tell me the difference between a Stollery Crazy Tube Marblehead and a canting keeler. A canting rig would amost certainly be much easier to achieve (and lighter, and more forgiving) than a canting keel. You might even sneak it in in a legal Footy somehow.

It does have one big disadvantage, though. You can’t see the pretty graphics on the topsides so easily. Life sucks doesn’t it. :graduate::devil3:

34

Angus -

a while back AMYA magazine had an article of a canting rig AND rudder within the developmental US 1 Meter Class. Had photos of it canted to windward (out of water) and some technical stuff. Will see if I still have a copy lying about. Rudder canted to side to remain parallel and in line with mast.

As for the very nice multihull compliment - thanks ever so much. You’re not such a “bad guy” after all ! :rolleyes: :lol: :winking:

35

But but but … Angus, you’re sidestepping entirely … what happens when a wide boat goes to windward … she heels and becomes that narrow-hulled, ultra-light displacement boat that you’ve just argued works so well … it’s what makes them fast both going both ways …

pogo1.jpg

6.5minigal-10315.jpg
6.5minigal-10315.jpg480×652 26.8 KB
mini-transat-1.jpg

… and as argued previously, for a footy, no need to cant the rig or move the ballast, just hang the ballast lower … you can still get a stiff enough boat …

… to boot, they may be rule-driven, but compared to an AC rule the Open rules irrespective of size is downright anarchy …

36

I’m with tmark on this. Look at two relatively unlimited rules: Seawanhaka on full size domain and the German displacement-only class for models. You get the same type forming:

  1. Beamy, light displacement boat with looong over hangs and a wide transom.
  2. Rounded sections in the forebody to give nice easy buttock lines.
  3. Gradual hardening of the bilges as you go aft with a flat floor for planing.

Now look at the heeled and upright waterlines. Heeled, relatively little of the boat is in the water, the heeled waterline is nice and easy and she stretches out on her sailing lines to get a long effective LWL. Upright, she pays a penalty on LWL but the wetted surface goes way down and planing/surfing/intermediate mode is facilitated. The principle is nicely illustrated by the attached picture of “Manchester,” the 1905 Seawanhaka Cup winner.

If you’re still a skeptic, take a look at this:

http://www.youtube.com/watch?v=_Ex2dFFhpCw

Of course, all this speed comes at a price: nasty, wet boats that’ll pound the fillings out of your teeth and that really want to pitch you into the drink.

Interestingly, the same basic form, with shorter overhangs and higher freeboard, was used on the TNZ AC32 boat.

As an aside WRT the minis, people were building boats with twin rudders in 1900 or thereabouts.

So I think that form is the natural form for optimum monohull performance and it’s the other shapes that are artifacts of class rules.

Cheers,

Earl

37

Another example of a flat bottom boat for downwind planing and when heeled for upwind sailing a significant number of surface square feet is reduced. Talk about a huge change in water line shape ! :tand:

Boat by the way is a Class “A” Scow - and popular here in the Midwest ! Length is just under 38 feet and beam is just over 8 feet. Magnificent ride !

38

Earl,
Funny that you mention the scow hull form, because as soon as I looked at your thumbnail image that’s what came to mind. In fact I’ve got an old postcard c 1905 that shows a very similar looking boat on one of the local lakes.(pic 1) They still do alot of scow sailing on these Midwestern inland lakes & this one appears to have been one that evolved into what is now known as an “A” Scow (38’ LOA) The 2nd card is postmarked 1921, still with a gaff rig. Then, there’s the more modern day stuff…tsk… tsk…they forgot to retract the windward bilgeboard (pic 3, credit Tim Stanton). Then, just to round things out as an eye candy counterpoint, here’s a totally restored 1948 Luders 16 (LOA 26’)(pic 4). Of course, the Footy class rules preclude using the “moveable ballast” that any full sized scow obviously relied upon. I would really like to see Niel’s grandfathered-in scow-footys compete against narrower displacement hulls.
Regards,
Bill

39

At last gentlemen! I have been arguing this point since i joined the forums!!! you have put it beautifully.

40

Someone once told me that multihulls go downwwind quite quickly, despite their sknny toothpicks of hulls. Sorry, gentlemen, I bow to your superior knowledge. I must have misunderstood.
:devil3: