Design Trends

Notes on Footy design trends.

The Euro GP was successful in a number of ways. One was that it allowed a reasonably direct comparison between a wider variety of signs and ways of thinking than is usually possible.

Please note that these notes are purely my personal views. If anyone is offended, they should feel free to defend themselves. No harm or insult is intended, even to Gary Sanderson.

The boat of the meeting was undoubtedly Duck. Narrowish, lightish, well-balanced and well-sorted with a distinctly cod’s head & mackerel’s tail hull form She reminds me very much of the Miller (later Lexcen) Admiral’s Cuppers Ginkgo and Apollo II of 1973 vintage. She is devilishly fast in heavy air, particularly upwind. At one stage I had her transmitter pressed into my hand whileGary did something and was astonished how easy she was to sail

Probably the most interesting boat was Flavio Faloci’s Folgore (Thunderbolt). When I first saw her in my hotel room two nights before, I must admit that my hart sank. Here was this nice man who had come all the way from Italy t compete using what was obviously a semi-scale character boat However, it soon became apparent that the ‘semi-scale’ and ‘character’ features are cunningly styled manifestations of some very clever and highly original thinking intended to produce a very fast Footy indeed.

She is narrow and fairly with a ‘soft chine’ hull form. She is far from light (about 500g if my memory serves me right) but the overall immersed depth of the hull is not as great as you might think. The rocker is concentrated in the ends so that in profile she looks rather like the underwater part of a ‘bustleoid + double chin’ 12 metre (e.g. Southern Cross). However, the sections are trapezoidal throughout with substantial flare – even amidships. Combined with a fine spring to the sheerline, this gives an imposing ‘Mediterranean fishing boat’ bow which definitely appears to be effective in keeping the water where it belongs.

All this is minor detail compared with the rig – a traditional (-ish!) gaff rig complete with numbers in some antique font and wooden spars (including a long and questing bowsprit – she should have been called Espada) in beautifully laminated balsa. Very pretty – but performance – nah. Now stop and think. This rig gets loads of sail area low down. Centre of effort is low and the B rig can generate bags of power. Forget the idea that gaff rigs really will not go to windward. This largely stems from the excessive twist caused by heavy wooden gaffs falling off to leeward, unrestrained by stretchy natural fibre sails. In reality most modern AC rigs are gaff but using carbon battens and massively strong sailcloth instead of flax canvas and Norway spruce.

Performance on the water was impressive (especially when you consider that you could still smell the varnish in the bilge) until her sail servo died. Even then with the sails permanently trimmed for a close reach she did remarkably well. A boat to watch in future.

My Voortrekker design was a disappointment. After a good second in the first race she faded into nothingness. Michael van den Peet puts this down to poor tuning through lack of time (why do people have to move houses) and says that she is now much better trialling against Duck. As it is Moonshadow – which is competitive against Duck – was left in the cupboard.

The other revelation of the series was Charlie Mann’s Lajabless. I must admit that, although I hugely admire Nigel’s building I had never been particularly struck by the Lajabless as a design. In reality she managed to carry a huge rig during the windy Saturday races and was right up there with the leaders, failing to sink, submarine or do any of the other nasty things that every KNEW were going to happen. She faded somewhat on Saturday, her new light-weather McCormack rig notbeing quite up to the mark. If the origina rig restrictions are to continue to apply, optimising one of these boats in terms of sail area versus bulb weight becomes a very interesting conumdrum.

The ‘conventional’ medium-wide beam, medium displacement boats (Cobra II and Mistralette) did consistently pretty well, as is evidenced by their coming out 2nd and 3rd respectively

To my mind these were the most interesting design observations on the series. If anyone has different views, argue now – or better still come back next year to prove your point on the water. Even better, do both!!

Would things have been different had the Bugs of Stollery and co been present?? or the undeniable power of the Southwater fleet??
I Don’t know…thats why I am asking.

Still more questions than answers.

dear Angus,
many thanks for your kindly and careful review of my boat.

I have only one or two points to add to your wise words

-Her hull design is a loosely similar to brett new boat ( bob2 ) even if she is not a diagonal boat
-Overall beam is 102 mm, but waterline beam is around 80 mm - only -
-Displacement during Birkenhead days was 484 gr, using an heavy keel
Here in my sunny Italy she will use a smaller ballast bulb, and displacement will be lighter ( somewhere between 400 and 450 gr )

I am currently working to replace her broken servo, making a new mainsail and fine tuning her in order to enter internet course
Less than one week is left, and I have to build the race buoys too…

Up to now her plans are a huge mess of sketches, but I hope to have something more “user friendly” to be posted for “free download”
stay tuned…

meantime … these are few pictures showing her details

Flavio ( the nice man had come all the way from italy ) :wink:

PS
I have been also very impressed by performances of Charlie’s lajabless
But don’t forget that he is a very skilled modeller with more than half century of experience . His boat was wonderfully outfitted and very well steered

There is a class of competition aeroplanes called “Bostonian” which have class rules which produce, and are intended to produce, a chumbly little plane with quirky resemblance to real planes.

In the scoring system there are points for scale features, flying performance (duration) and “Charm”. The charm points are important when things are closely balanced and hotly contested.

Flavio get my charm points, and his Folgore gets a lot too:D. Thank you for showing us the inside layout. You have made Angus very happy with your rudder operating mechanism!

If you gather the plans and make them available we will be very grateful. Do we have to construct her using traditional boatbuilding tools? Adzes, augers and trenails?

regards

andrew

Oh, yes, and Angus’s original analysis.

Duck has a lot going for her, and is, as you say very friendly to sail.
She has interesting features which are clearly not harming the hydrodynamics too much - the fin is very low on area, and set very far aft, and the rudder is not short on area or movement.

A feature of Duck which I took on board when a footy virgin is that the servos poke out of the deck - this is also a feature of Bugs and successors, and would never have been adopted by Roger S if it did not confer winning potential.

Bill’s changing of a rudder servo between races at Birkenhead showed the sheer utility of making them accessible.

I will never bury a servo again, and I will probably steal Gary’s modular idea of mounting them on a detachable board as well.

andrew

Removable servo trays are standard equipment for serious racers in the M class. Here in the US you are allowed 5 minutes to effect repairs. Isolating the malfunction is sometimes more elusive than just replacing a servo. It is far faster to just bring along a back-up duplicate servo tray and worry about fixing the failed r/c gear when you are no longer racing. Duplicate servos are not that expensive now and setting up a removable servo tray system does not add any appreciable weight if done well.
This remedy also helps you keep your head in the game, you won’t be worrying, while racing, about wether your repairs will hold up or wether it will fail again.
I use removable trays on every boat that I build. When I travel to races I bring along one or two back-up units. I don’t like going someplace to race and becoming a spectator.

to make andrew happy, these are more detail of inner layout of my footy

I also think that my next boat will be fitted with servos on deck ready for a quickly replacement and also to reduce leakages point such as tiller rod hole, and sheets hole on deck.

flavio

… and these are the pictures

Beautiful mate!

Your attention to detail is very inspiring. Working on a personal build that is similar.

:zbeer:

Design trends eh??

Pictured below is “Shinzo” a 350g free sailing footy circa 1998
Beam and waterline beam and general shape are similar to Folgore .
Whats old is new again??? Shinzo was very quick,BobAbout was built a week later but was fattened up in all directions for heavy r/c equipment.Maybe with the lithium batteries,light servos and a deeper keel Shinzo would be as good or better than many current designs,my own included??

So,
Heavy Bugs(and close relations) 1 ,2 and 3 at Watermead I believe.
How did the long light boats go in the light conditions?

Badly. However, the gneral ooinion among those who were there is that the dciding factor was not beam or weight but rig In drifting conditions swing rigs seem to have been vastly superior to McCormack rigs (or anything else). As soon as there was any wind at all, this superiority went away.

As an indication of how light it was, the last race took about 30 minutes.

Brett,

An attempt at an answer - 4th was Trevor’s Mistralette, the first Macrig home and a wide, rounded hull. I dont have any results lower than that but Gary S must have been well up with Duck.
The Voortrekkers came nowhere - I did not have enough sail, had radio problems and had to deliver my lad to his sister’s house in the middle of the day.

My tentative conclusions were that the day was not about hulls at all - it was about sails and rudders.
I saw that the swing rigs were driving their hulls when none of the macrigs were moving at all - I THINK this was a function of sail area and height
Certainly without enough rudder you could have no control and no ability to “tack”

If I had the facility I would have unballasted Razor and fitted a very tall rig, and gone for the Sanderson-size rudder. Fitting a very light keel would have cut the wetted hull and there was NO need for the big righting moment that day.

When I commission Sloice there will be provision for making all these adjustments. The perceived need for a lighter keel is a new one on me. Sloice also will have “buoyancy bustles” which can be changed to suit the conditions as well.

sorry - not a reasoned exposition of the designs and positions - more a personal spiel

andrew

I think that says more about the individual rigs present rather than the merits of various rig “types”.
Light airs always brings the best skippers and tuning to the fore…its easy to race in constant breeze.

Brett,

At Watermead my Mistralette was running a 205 sq inch McCormack rig with a 550 mm head height ( sorry about the class of units but I just find 1323 sq cms difficult to visualise )

Anyway, I think the boat’s main problem was one of sail and hull balance. I think the basic hull is what is called powerful, in that it seems to be able to cope with quite large sail areas in all points of sailing except downwind. Here it bacame virtually uncontrollable - to the point of loosing all my upwind advantages. To this end I had spent the week prior to Watermead changing to Lithium batteries, altering the battery position in the hull to raise the bows a bit and finally fitting a rudder of similar area but unbalanced and protruding further aft. I have subsequently calculated that the net result of these mods was to push the Hull CLR 5 mm or more further aft. Needless to say I hadn’t thought to change the sail as well. In the very light breezes at Watermead
( now thats what I call Sod’s Law ) I had too much tendancy to turn away from whatever breeze there was and because of the very low speed even my new rudder was unable to compensate. I have since bent up some shorter Z pieces and am now just waiting for the right test conditions.

What probably happens in any normal wind is that small changes in helm can be compensated for by more rudder angle - O.K. I probably go slower than I should because of this but it is not as noticable as with lower breezes.

Finally, what would you recommend for the Z Piece pivot. At the moment I am using 1/16 inch diameter piano wire Z Piece with a point on the end in a carbon tube with a short length of brass rod at the bottom for the wire to bear against. Do you think is would be worth while sleeving the carbon tube so that the wire only touched it at each end rather than its full length ? The rig itself is fairly well balanced for weight.

It was quite noticeable at times how much earlier the Stollery type swing rig would actually swing compared to my McCormack. Of course, his mast doesn’t have to rotate so he has less inertia and his main and jib booms are connected by just a piece of wire looped around the mast so friction is minimal.

Cheers,

firstfooty

Hi Trevor,
Lee helm is a complete no no if you want to sail fast,It is vital to have a means of altering helm balance.
With regard to the rigs balance itself…you should be able to make your rig move by blowing across the room.If your rig does not move with this test then it is not sensitive enough.
With the Mac rig this is acheived with light weight,a very free moving pivot and a counterweight to balance the rig exactly.

Update…I understand the leading skippers built larger rigs especially for this event.well done those guys.