Just received the final design and report on the Bantock designed F100 CBTF–and it is remarkable!
Anyone who has followed my design reports knows that I have reported the good with the bad; even mentioning that some initial data suggested that the CBTF concept would not work well in every condition on models this length but that CBTF was faster in winds of 6mph and over. I tried to point out that those results were not final results but were preliminary and could change. Some people drew conclusions from my reports that are now totaly disproved!!
The F100 final design is shown to be faster in every condition and by large and consistent margins -some approaching 500 seconds per mile!!! In light and heavy air! In Grahams own words:“Generaly the CBTF concept can provide a fast boat in the Open One Meter Class(F100) at all windspeeds and on all courses compared with a fixed keel version. The fixed keel version of the OOM(F100) is itself much faster than a standard International One Metre.”
Interestingly, Graham Bantock used the services of the Wolfson Unit for Marine Technology and Industrial Aerodynamics to refine the VPP’s capability with regard to the special issues regarding a CBTF model. The Wolfson Unit is the same organization many America’s Cup Syndicates consult with.
The new design is quite narrow and will carry around 1300 square inches of sail on a square top rig with a 7.2-7.4 pound displacement.
UPDATE 12/5/03- removed the words CBTF RULES!!! because it implies more aboutCBTF than we know for sure now.(Thats not how I meant it: I was trying to say that CBTF had proved out in the design studies to be superior toother canting keel formats) We know that the design studies suggest that CBTF will rule and that as compared to several other variations including fixed keels this design appears superior. Time will tell if this proves out on the race course…
UPDATE:2/5/04- tooling to be started very shortly; new design canting keel trunk being tested-trunk allows fore and aft keel movement if wanted , keel rake adjustment and easy keel fin removal.Also eliminates characteristic “bump” under hull.If new system proves out it will be used on the F100CBTF. Research on lateral resistance has yielded interesting dividends-more soon under a separate topic.
Doug Lord
Brett, it will be after we’ve sailed a few of the new boats so some time next year; I have no idea at what cost but I’ll post it on the website when I do.
Following are some comments about CBTF reported in the Sept. 03 issue of the worlds finest sailboat racing magazine: Seahorse. Most of the comments apply equally well to the Formula 100 CBTF designed by Graham Bantock.From an article on the Admirals Cup by Tim Jeffery pgs, 34-35: : “Yet Wild Oats(60’ CBTF raceboat by Reichel-Pugh) was the eye-catching yacht of the series. Not since Dick Carter’s Red Rooster in the 60’s has a yacht aroused such curiosity for what goes on under the water.That’s because of her Cating Ballast Twin Foil technology which designers Jim Pugh and John Reichel have taken under licence from Chuck Robinson’s CBTF Inc. Robinson’s company used to be known as Dyna Yacht and the roots of the steerable twin rudders can be traced back to Tom Blackaller’s 1987 12 Metre USA and the work done then and since by Alberto Calderon. Where USA had just a strut to carry the ballast bulb(remember ‘the geek’),CBTF have moved on to make the strut canting in Open 60 style.
The twin foils not only provide lift,dial out leeway and even allow slide-slip tricks, but they manage the wave drag formation by flattening the trough.Once you start down this path the gains keep coming. Because the righting moment of the canting keel is high the ballast can be smaller,so the displacement reduces.And so on.”
From Bob Oately the owner of Wild Oats as quoted in the same article:" The concept of the keel is one of the greatest things to have happened in Yachting,the boat sails like a Laser;delicate and wonderful.But she’s also very safe-she always stands up again."
From Mark Richards on Wild Oats remarking on the Australian victory in the Admirals Cup led by Wild Oats:" The convicts have beaten the King!"
From an article on the new CBTF boat Genuine Risk starting on page 38 of Seahorse: on why CBTF was chosen: 1)-…“the flexibility of the forward rudder in terms of CLR movement(center of lateral resistance) was attractive.”
2)“The keel structure has been engineered to support an extreme fin and bulb design,with the bulb suspended more than 4m below the hull and the ability to cant the keel up to 55 degrees either side of centerline”.
Note that this is the same cant angle on the F100 CBTF that has a 4.4 pound bulb suspended 19" below the hull and a two second total transit time full out to full out(one second center to max out).
Performance of the new model is sure to open many eyes to the exciting potential of this new technology in rc raceboats.
Most people would just like to see a new boat sail; this is the first time I’ve had specific requests to see any boat sail in under 3k and at over 20 in a three foot chop!!! I wonder why?
At any rate, the building sections should be in by Monday and the plug started soon -with tooling complete in a couple of months or so…
Dimensions of the new boat: LOA- One Meter; Beam: 6.25 inches; displacement 7.2lb.'s; SA: 1300 sq.inches in a reefable squaretop rig; Ballast 4.4lbs on 19" fin; Max draft 22.6". Cant angle 55 degrees each side of center.
Note: The Formula 100 CBTF One Design fits within the F100 Development class without modification but owners can choose to have their own F100 A,B, C rigs(or more) for racing within the F100 Class.Only the stock rig and stock mechanics are legal for One Design racing.
For F100 Development class racing hybrid Power Ballast Systems are also legal (combination canting keel and on-deck rack etc.)
Doug Lord microsail.com monofoiler.com
High Technology Sailing/Racing
Doug, I regularly sail in in the conditions I mentioned. You’ve been very quick to say the boat is the fastest one metre period. So are you going to start with the caveats now? As an FYI, Roy and my posts just describe what racing conditions we sail in our locales.
Rob, I don’t think there are any “caveats” in anything I’ve written…
There is no question that this boat will be very fast in every condition
especially as compared to an IOM…
At the suggestion of Graham Bantock David Hollom will be optimizing the foils on the new F100CBTF. He is a world renown aero-hydrodynamacist with extensive credentials in full size and rc yacht hydrodynamics.
I am talking to Simon Rogers of Rogers Yacht design, designer of Jonathan McKee’s
mini 6.5(leading the mini transat currently) regarding the unique canting keel arrangement in that boat. The canting keel move’s side to side AND fore and aft BY HAND using a block and tackle arrangement . The fore and aft movement helps to prevent nose dives by these little ocean racers and if incorporated in the F100CBTF boat would do the same thing. I’ve been working on a solution to this for a long time and am not satisfied with the solutions I’ve developed . The rocker in Grahams design may prevent significant movement but I’ll soon know Simons ideas on the problem. Additional considerations are how much additional weight would be involved and how much additional power.The ideal solution would use a very small servo to vary the range of movement from slightly forward to max aft with the grunt work being done automatically by the mainsheet winch as the sails are eased.Since the keel fin is not used for lateral resistance on a CBTF boat movement of the fin is irrelevant from a balance or control standpoint.
Dario seemed to feell that the high sail area to displacement ratio of Phie allowed it to scoot out in the puffs rather than nosedive. So you may not hav a problem here. Before you add too much extra complexity, I would make sure there is really a need for the extra degree of freedom.
Will at this point I’m investigating Simons concept; I dont’ think it is likely to be usefull for a number of reasons and I’m reluctant to add any more complexity to cover a downwind heavy air situation–there are other potential solutions. But maybe I can learn something that will be of benefit-I’ll be talking to him in a few minutes and will edit this post with his ideas and my impressions later…
UPDATE: what a delightful guy to talk to! He’s an “evangelist” like I am regarding his concept and is elated that Jonathan McKee is now 60 miles out in front in the mini transat. Graham is going to send him a planveiw of the boat and the hull sections and Simon will look at the possibilities–then we’ll talk more.
Update: sometime soon, I hope, perspective views done by Graham Bantock of the F100CBTF raceboat will be posted on microsail.com
Doug Lord microsail.com monofoiler.com
High Technology Sailing/Racing
See the IACC topic under “General Discussion” for much more on CBTF…
UPDATE 10/20/03 : see very detailed design specifications of this new design under the “Hull Shape” topic in “General Discussions” on this forum-posted this date.
Doug Lord microsail.com monofoiler.com
High Technology Sailing/Racing
Have just received the final building sections and the foil sections from David Hollom. Hoping to hear from Simon Rogers soon on his fore and aft sliding/canting keel…Will start tooling just after the first of the year…
will this new boat be able to take done the ts2 ? i have seen the ts2 perform and for a IOM boat, it is very fast and quick. will the fb100 be able to beat this boat in all conditions. because I sail in all conditions. my club sails in a secluded pond where the wind can go from 3 knt up to 10 knts. but I also put my IOM in lake ontario and lake huron wher the wind and waves can realy pick up. now with me saying that, My IOM cannot keep up with a ts2 but the people who have ts2 do not put them in a great lake.(and why should they the ts2 cost $2000 +, my boat cost be all of $600 and that is with the radio)
cougar
LLoyd Ertel
Cougar,it is impossible now to say whether the actual F100CBTF is faster than a TS-2; only racing the boats will answer that.
Bantocks design analysis showed that the F100CBTF was faster than a fixed keel IOM by very large margins on every course and in every condition; these are design predictions by one of the best model yacht designers around.
The logic can be seen if the boat is looked at a little closesly: it has 30% more sail area and the power to carry it in higher winds than the IOM can carry an A rig; the 19" (483mm)canting keel while canting 55 degrees to one side develops more RM than an IOM is capable of at a sailing angle of only 15 degrees. The projected all-up weight of the new boat is about 1.4 pounds(.63kg) less than an IOM.
The new boat also uses a feature of CBTF called “collective steering” which allows a CBTF boat to have a significantly better upwind vmg than a “normal” boat(ZERO LEEWAY).This feature was not even included in the performance predictions made by Graham… See the topic in Technology that explains how CBTF works.
All the indicators of performance prior to actually sailing the boat predict that it will be very fast especially against an IOM of any design. Racing results from France show that the fixed keel F100 is significantly faster than IOM’s and Grahams design study also compared the CBTF boat against a fixed keel F100 showing that the CBTF boat was faster in all conditions and courses but at about half the margin as compared to IOM’s.
The only real answer will come with actual racing on the water…
doug
graham is one of the best in the business , there is now question about that. and if you are right. it carries more sail and with a lighter hull the boat should (in theory) accelerate faster. and therfore when tacking. the boat shoudl come into a tack faster and come out of a tack faster. but i seem to remember when IOM had to be narrow to be fast, then the ts2 came on the scene and everybody went wide. we even have a clone a v3. but i always belive graham knows what he is talking about , are we talking about a IOM boat that will come with a $2000 price tag?. if that is the case we just might be puting the class into the hand of the people who can pay to get a winner and the sailor become second
LLoyd Ertel
LLoyd,the new boat is not an IOM-I wasn’t sure I’d made that clear. The boat will eventually sell for about $2000-2100 ready to sail including a PCM radio-I guess. That could change as we find better ways to do things…
PS-current price is posted on the website…
Doug Lord
–High Technology Sailing/Racing