FRANK BETHWAITE - 49er DESIGN - GRADIENT - WIND AND SAILS - HIGH PERFORMANCE SAILING

Francis « Frank » Dewer Bethwaite  1920-2012

par François Chevalier & Jacques Taglang

©François Chevalier

C’est la profonde passion pour l’élément aérien – l’air, sa variété, sa richesse, sa force – qui caractérise le plus Francis « Frank » Dewer Bethwaite le célèbre concepteur, avec son fils Julian, de l’International  49er Class. Depuis l’an 2000, le 49er est le dériveur olympique haute performance à deux équipiers.

La passion de l’air..., acquise en tirant des bords sur la rivière Wanganui sur de petits voiliers de sa conception – déjà ! – en Nouvelle Zélande où est né Frank en 1920. Passion confirmée lorsqu’il s’engage dans la Royal NZ Air Force pendant la Seconde Guerre et poursuit une carrière de pilote de ligne après les hostilités. Passion fortifiée puisque Frank s’adonne également au modélisme aérien pour comprendre et améliorer la forme des ailes en compétition. Quelques années plus tard, fort de ses essais et analyses des courants thermiques ascendants il établit un record de vol d’endurance ininterrompue de 9 heures suivi d’autres performances mondiales !

En 1959, Bethwaite déménage avec son épouse et ses 4 enfants à Sydney, Australie, pour travailler au Commonwealth Scientific and Industrial Research Organisation (CSIRO) pour travailler sur le projet visionnaire de l’ensemencement des nuages. Il monte ensuite une petite fabrique de mâts où il installe un tunnel à soufflerie pour en améliorer le profil. Son mot d’ordre : une expérimentation n’est valable que si elle est mesurable et reproductible à l’infini. Dans le domaine des gréements son sens de l’innovation est désormais reconnu.

L’air encore : en 1972 et 197 Frank Bethwaite fait partie de l ‘équipe australienne olympique de voile en tant que météorologiste. Il écrit ensuite le fameux succès mondial, High Performance Sailing puis cosigne avec Ian Bruce le dériveur léger à deux équipiers : Tasar. Frank réalise les plans de nombreux 18 pieds de la baie de Sydney, puis, avec l’un de ses fils, Julian, il initie le 49er.

Toujours à la recherche de meilleures performances pour les voiles, il n’a de cesse d’imaginer des simulateurs pour trouver à quelle vitesse le flux d’air décroche de la surface de voile. Des travaux que ce passionné menait encore quelques temps avant son décès intervenu le 12 mai dernier...

GRADIENT : un des sujets favoris de Frank

Lorsque le vent rencontre une voile, il est dévié de sa direction. Donc, si la voile a une action sur le vent, elle exerce une force sur lui. Par définition, cette force est aérodynamique.

Un voilier en pleine mer provoque sur le courant général de l’air une déviation qui peut être localisée. Sur la zone au vent du voilier, il y a compression des filets d’air contre la voile. Par contre, sous le vent, les filets derrière la voile sont obligés à suivre la courbure pour combler le vide, il y a succion. La compression et la succion sont des forces aérodynamiques.

 Les forces sont perpendiculaires au plan où elle s’exercent, quels que soient leurs angles d’attaque. Elles sont proportionnelles à la surface de voilure et au carré de la vitesse du vent. Sachant que le vent n’est pas constant du bas en haut du mât et que les profils sont déformables, ni d’allongement infini, la théorie est assez loin de la réalité. Il suffit de choquer ou border une voile pour se rendre compte que l’effet est immédiat. 

Francis « Frank » Dewer Bethwaite  1920-2012

par François Chevalier & Jacques Taglang

©François Chevalier

It is his deep passion for the air element – its diversity, its richness and strength – which most characterizes Francis “Frank” Dewer Bethwaite the famous designer, with his son Julian, of the International 49er Class. Since 2000, the 49er is the Olympic men’s two persons dinghy high performance.

The passion of the air, acquired when learning to sail on Wanganui River aboard small sailboat he built in New Zealand where he was born in 1920. Passion confirmed when he joined the Royal NZ Air Force during WW II and after hostilities when joining Air NZ. The passion … confirmed when he experimented with model airplanes to find the most efficient wing shapes in competition. Some years later, taking full advantage of his trials and tests about thermal lifts, Bethwaite won the endurance record of 9 hours aloft, followed by other world records!

In 1959, Frank moved with his wife and four children to Sydney, Australia, and worked for the Commonwealth Scientific and Industrial Research Organization (CSIRO) for the visionary cloud seeding project. Then he founded a small manufacturing company producing wooden masts where he built a small wind tunnel, which leads him to improve his spars. Frank was only satisfied if his experiments were measurable and repeatable.

Air element at last! In 1972 and 1976 Frank Bethwaite assisted the Australian Olympic Sailing Team as the team meteorologist. He also wrote a world wide best seller, High Performance Sailing, the co-designed with Ian Bruce the famous dinghy Tasar. He finally designed many 18ft skiffs of Sydney, then the 49er with one of his sons Julian.

Always looking for better sail performances, he worked on sailing simulators to find at what speed the flow became delaminar. Few times before his death, last May 12^th, he was still working on this question!

GRADIENT: one Frank's favorite subjects

When the wind hits a sail its flow is deflected in its direction. So if a sail has a direct action on the wind, it exerts a force on this wind. By definition this force is aerodynamic load.

A sailboat in the offshore creates a deviation on the general stream of air that can be located. On the windward area of the boat, the airflow is compressed against the sail. On the other hand on the leeward area, the airflow behind the sail has to follow the curve to fill the vacuum; there is suction effect. Compression and suction are aerodynamic forces.

Forces are perpendicular to the plan on which they operate whatever their angle of attack. They are proportional to the sail area and to the square of the wind speed. Given that the wind is not constant from bottom to top of the mast and that the profiles are deformable nor infinite stretching, the theory is rather far from the reality. You only need to ease or to sheet in a sail to immediately realize the immediate effect. 

VOLVO OCEAN RACE - YACHT DRAWINGS - DESIGN EVOLUTION - 2001-2002, 2005-2006 & 2011-2012

VOLVO OCEAN RACE 

Errare humanum est...

Dans nos précédents messages, nous avons publié par erreur, à deux reprises, les plans de GROUPAMA dessinés par Juan Kouyoumdjian et oublié de présenter les plans de CAMPER réalisés par Marcelino Botin... Voici les plans de CAMPER !

In our previous message, we have published twice the Juan K's GROUPAMA designs and omitted to publish Marcelino Botin's CAMPER. Here they are !

©François Chevalier

©François Chevalier 2012

GERHARD RØNNE'S RUNA IV 1918 - YAWL RUNA IV 1918

RUNA IV: LINES AND SAIL PLANS

As I explained last April, I’m working on the project of a large book dealing with the Danish building architect Gerhard Rønne (1879-1955) and the boats he designed in his spare time.

And, as usual, the book will be illustrated by the designs of all his yachts redrawn by my friend and long-standing partner François Chevalier.

François has already followed the refit of the gaff yawl RUNA IV (1918) – rebuilt by Chantier du Guip at Brest (France). He is also in charge to redraw the gaff cutter RUNA VI (1927) that will be refitted by the same boatyard. RUNA VI should be re-launched next year. Both yachts are under Yves Carcelle’s ownership.

Please enjoye François superb work!

Jacques Taglang

ALL THE FOLLOWING PLANS AND DRAWINGS OF RUNA IV: COPYRIGHTS FRANÇOIS CHEVALIER

ALL THE FOLLOWING PHOTOS: COPYRIGHT NIGEL PERT

GERHARD RØNNE AND HIS YACHTS: RUNA - RAN - MAISIE - EHLY - FRIGG - DANISH YACHTING - DENMARK

I’m currently working on a large book about the Danish building architect Gehrard Rønne (1879-1955) and the boats he designed in his spare time. I NEED HELP! I'm looking for more information than wikipedia can provide about Rønne's biography!

by Jacques Taglang

Somebody could help me to find the descendants of Gerhard Rønne?

What I know about Gerhard Peter Rønne

Born in Copenhagen on March 6, 1879

Died in Copenhagen on Mai 12, 1955

Gerhard was the son of Niels Christian Rønne

Born in Copenhagen on 1849

Died in Copenhagen on 1930

And Augusta Maretta Jeppesen (?-1914)

Gerhard Peter Rønne married

Ines Jensen (9/7 1890 -?) in Copenhagen on May 11, 1911

Gerhard Peter Rønne and his wife Ines Jensen had a son:

Torben Henning Rønne. 

He was a diplomat.

Born in Frbg, Copenhagen, on April 14, 1919

Died in Moscow on October 19, 1973

Torben was married twice:

A/ He first married Ines Kirsten Henriette Alexine Hofmann-Olsen, in Svendborg on February 16, 1945. The marriage was dissolved on 1947.

Ines Kirsten Henriette Alexine Hofman-Olsen (born on November 25, 1923 in Copenhagen – died ??). Her father was Thorkil Hofman-Olsen (1884-1966) and her mother was Margrethe Johanne Staalesen (1903-?).

B/ He then married Bergliot Marie Consuelo Langgaard, in Oslo on June 23, 1949.

Bergliot Marie Consuelo Langgaard (born on February 26 in Oslo – died on February 14, 1976 in Copenhagen – Sions cemetery). Her father was Karsten Frederik Langgaard (1900-1944) and her mother was Bergliot Marie Røwde (1903-?)

DID TORBEN HENNING RØNNE HAVE HAD CHILDREN?

Please contact: jactag@gmail.com

  In fact, Rønne only drew up 10 yachts…

- RUNA 1910 – wooden keel gaff cutter

- RAN II (1910) – wooden keel gaff cutter

- RUNA III (1912) – wooden keel gaff cutter

- MAISIE ex-RUNI (1912) – wooden keel gaff cutter

©Nigel Pert
- RUNA IV (1918) – wooden keel gaff yawl

- EHLY (1918) – wooden keel gaff cutter

- RUNA V (1920) – wooden keel gaff cutter

- RUNA VI (1927) – wooden keel gaff cutter

- FRIGG ex-VITA II (1936)? ?

©Gregory Ryan
- RUNA VII (1939-1947) – wooden keel Marconi cutter

The saga of the only 10 yachts is amazing. More to come!


Jacques

AMERICA'S CUP - AC45 ALEPH

BYE BYE ALEPH

On Tuesday, April 3^rd the CEO of the French Team Aleph announced the withdrawal of the team for the next 2013 America’s Cup… due to a lake of funding!

There should be only one French cat in 2013 in San Francisco: Energy Team managed by the Peyron brothers. We will be minded to follow their campaign.

Let’s go back to ALEPH. Sadly, it is the opportunity to pay a tribute to this interesting team that will be missing in the next Cup. So, many thanks to:

- Bertrand Pacé, skipper and tactician. Involved in the Cup for 30 years!

- Alain Gautier, helmsman and technical coordinator,

- Philippe Ligot, CEA

… and our friend Marcus Hutchinson, communication manager.

The good and attractive performance of Aleph in the three 2011 ACWS in Cascais, Plymouth and San Diego and the brief and final salute of the team in Napoli in April 2012 will be remembered. In any event Aleph owns to the Legend of the America’s Cup.

François Chevalier & Jacques Taglang

AC45 ALEPH 

Le mardi 3 avril dernier, le directeur général de l’équipe française Aleph, annonçait son retrait de l’aventure dans la prochaine America’s Cup 2013... Faute d’avoir pu réunir le budget nécessaire à la poursuite de son projet.

Il ne devrait donc y avoir qu’un seul catamaran français en 2013 à San Francisco : Energy Team menée par les frères Peyron. Nous aurons à cœur de les suivre dans cette fascinante aventure !

Mais revenons à ALEPH. C’est hélas l’occasion pour nous de rendre hommage à cette belle équipe qui va indiscutablement manquer sur la scène de l’America’s Cup. Merci donc à :

- Bertrand Pacé, directeur sportif, skipper et tacticien du défi – trente ans de présence dans la Cup !

- Alain Gautier, barreur et coordinateur technique,

- Philippe Ligot, directeur général

- et à notre ami Marcus Hutchinson, responsable de la communication...

Les belles prestations d’Aleph lors des trois ACWS en 2011 à Cascais, Plymouth et San Diego et l’ultime et bref salut du team à Naples en ce mois d’avril 2012 resteront dans nos mémoires. Quoiqu’il en soit, Aleph appartient à la légende de l’America’s Cup.

François Chevalier & Jacques Taglang

VOLVO OCEAN RACE - YACHT DRAWINGS - DESIGN EVOLUTION - 2001-2002, 2005-2006 & 2011-2012

FOR THE FIRST TIME ON THE WEB


VOLVO OCEAN RACE YACHT DESIGNS - 2001 - 2012


Evolution of the Volvo yacht designs since 10 years !


The authors wish sincerely thank Donan Raven for his kind translation. Please have a look on his blog:

nuttyrave's sailing trivia

It's far better than my "Frankenstein" English! ;-) Thank you my friend! Jacques Taglang...




To carry out these lines plans, which I drew on tracing paper, I observed the hulls in build or ex-works, using their cradles as a source at times, and all the while bearing in mind the personalities and intentions of the yacht designers who had created them and especially in strict observation of the relevant rating rules. Thus I was able to draw them fairly accurately. As soon as the sailing boats received their keels, rudders and centerboards, I was able to finalise the plans for the 2001, 2005 and 2011 editions of the Volvo Ocean Race.


2001-2002

In 2001, the new rating rule which defined the VO60 authorised carbonfiber rigging, which gave real oompff to the yachts and profoundly changed their behaviour.


Out of eight candidates, six came from Farr Design: Assa Abloy, Illbruck, News Corporation, Team SEB and Team Tyco. The team at Nautor Challenge ordered two boats, amongst which one, Amer Sport Two, was designed by Bruce Farr himself, and the other, Amer Sport One, was designed by Germán Frers, Jr., AKA “Mani Frers“. Skipper Grant Dalton held back his choise until the very last moment, when he left the Farr yacht to Lisa McDonald's all-female crew. The eighth yacht was Norwegian entry Djuice Dragons designed by Laurie Davidson.






What stands out distinctively today is the narrow beam at the waterline on the one hand, and the hollow shape of the hulls on the other. Indeed, the three designers created narrow hulls, with as much external ballast as possible, with a tapered chine-bilge, as required by the rating rule, at broadest section of the yacht.




According to Bruce Farr, a yacht must be a skimming dish designed in compliance with the rating rule. His hulls feature angular lines, rather than flowing from a free hand: the forward sections are cut into an arrowhead along a plane that follows the deck from the bow to the mast. Then comes a 50cm vertical section, which is parallel on either side and extends far aft. The final angle is featured on the topsides, starting at a 45° angle from the bottom of the keel until the chain girth measurement. The cut extends all the way to the transom.


Laurie Davidson favoured safety instead and created comprehensively buoyant forward sections, though this penalised performance because it increased developable surface. The fin of Djuice's keel seems to develop greater area than other contenders.




Mani Frers' design displays greater stiffness, with wider topsides, as well as a sharper bow. The fin of the keel, which is positioned slightly forward of the mast, favours upwind performance, although this makes the yacht chase a lot more downwind. Her sail plan is far back, and the mast is close to amidships.


It is interesting to note that all ballast has been centred down the waterline, so the centre of buoyancy is located similarly on a


Incidentally, the Farr yachts took both first and second place, and Laurie Davidson had to make do with sixth place, though taking victory in the final leg.

2005-2006

For the next edition, the Volvo Ocean Race introduced the new VO70 rule. Longer, lighter, with greater sail spread, a canting keel and the choice of twin rudders; these yachts inherited from improvements developed in the America's Cup, the TP52 as well as the IMOCA circuits.




Juan Kouyoumdjian was the champion in this competition, his ABN Amro One taking 16 out 22 races and his ABN Amro Two establishing a new 24-hour distance record. Bruce Farr's four VO70s Pirates of the Caribbean, Brasil 1, Ericsson and Movistar took up the rankings in the middle of the fleet and the Australian entry Brunel, designed by Don Jones, finished in the last place.




Juan K's designs exploited every loophole in the rating rule, creating a larger, stiffer yacht, with a very sharp wave-piercing bow, a canting keel swinging on a hinge inside the hull, increasing stiffness further in upwind conditions, a skimming hull shape in after sections, deep daggerboards, lengthier keel with a narrower section. With more power and capable of planing extensively, these hulls established themselves as the fastest and announced a new trend.




Bruce Farr sought a fine and balanced design, with a rudder in the centreline of the yacht.




As for Don Jones, serving a project with limited funds, he created a more conventional yacht, with a round and wide hull, rounded forward sections, and with a very forward mast and a centerboard more forward still, and featuring a cockpit as way aft as possible.


2011-2012

©François Chevalier 2012

I did not have the opportunity to finalise the plans that I had prepared for the 2008-2009 edition, because no magazine expressed an interest to publish the lines of all five naval architects.

For the 2011-12 edition, with three contending designers, Juan K designed half of the fleet: the American entry Puma skippered by Ken Read, the French entry Groupama skippered by Franck Cammas and the Spanish entry Telefónica skippered by Iker Martinez. Farr Yacht Design carried out the plans for Abu Dhabi and was also represented by the Chinese entry Sanya (formerly Telefónica Blue) skippered by Mike Sanderson, who won the 2006 edition of the Volvo Ocean Race. Finally, Marcelino Botin, renowned for his TP52s, drew the lines of Camper for Emirates Team New Zealand.

Surprisingly for this "box rule", the three designers have produced very different yachts. Marcelino Botin created a superb development of a TP52: narrow, extremely sleek lines with a very forward centre of gravity, beam kept back to three quarter of the boat's length and lowrise transom, huge centerboards aft of the mast, which is itself centred in the middle of yacht.

©François Chevalier 2012

Farr's design breaks away from all trends. Assuming that these yachts should plane at the slightest of breezes, but would stop brutally in short waves, their hulls should be developed to plane as early as possible, and heel when beating without too much chasing forward, in order to raise stiffness, resulting in Abu Dhabi's huge round and full bow, with a sharp cutwater and vertical topsides. Here maximum beam is reached amidships and carries all the way aft, waterline is wide and centered, lines are sleek yet smooth, wth fine and elaborate centerboards, almost vertical and nearly inline with the axis. The forward deck is very cambered and the coachroof extends into it in a completely flush fashion.

©François Chevalier 2012

Juan K has developed his previous lines and optimised on numerous advantages established in the previous edition which was won by the Swedish entry Ericsson 4. The elaborate lines are obvious in the forward sections where the chine bilge extends all the way to the bow, with flat bottoms immediately after the cutwater in order to guarantee planing and to separate from the axis of the yacht when heeling to increase stiffness. The bottom aft is shaped to espouse and lengthen the stern wave and the wake that defines critical speed. All these characteristics demonstrate stronger ability for speed than other competitors, and the three yachts designed by Juan K currently head the fleet in rankings. 


However, it is to be noted that the three designers have shared the following: using the maximum beam afforded by the rating rule and fashioning keels, rudders and centerboards of similar shape.


The above lines plans have drawn for French magazine Voiles & Voiliers, but not all have been published. The last three appeared in the latest issue for the month of May, alongside commentary from a few sailors.


With regards to the damages experienced in recent legs, it must be observed in humble truth that the latest generations of yachts and shapes of yachts are developed for formidable performance such that has never been witnessed before, so the sustained impacts into head seas has only increased the stress and strain on mechanical parts and the hull itself. It is to the credit of the teams ongoing yachts if they have sustained no breakage.

Congratulations must also be handed to the sailors who have resisted so much wash on deck and so much discomfort above as well as below decks!

Please have a look on Donan Raven's blog: 

nuttyrave's sailing trivia

JUAN KOUYOUMDJIAN LETTER EDITED IN SCUTTLEBUTTEUROPE N° 2568/APRIL 12th 2012  Edited with the kind Juan K's agreement

With our 3 boats safely in Brazil and under the risk of sounding arrogant, I’ll break away from my golden rule of not speaking until the end of the race to put the record straight since I believe we are presented with an intentional manipulation of the truth.

There is a common, spread notion that ALL the participants of this VOR have structural problems, that the situation is unacceptable and that something needs to be done for the future. A fundamental distinction needs to be done between the mast breakages and the rest, and whilst I think it is very important to understand what caused so many mast failures, it is a travesty of the truth to put ALL designs in the same basket when it comes down to the “other” structural issues.

This generalization might suit a specific Team, or person to push any agenda he might have for the future, but out of respect of the hard and serious work done with my Team I need to speak up.

In the first edition of the VO70s, we had 2 triumphs to celebrate that as designers we are very proud of. One is obviously that our design was driven to victory by a very good crew and the other one is that our 2 boats were the only ones that completed the full circumnavigation without major structural problems. This celebration was faded by the public generalization that because one boat sunk and others had structural failures, then ALL of the boats had problems and the rules had to be changed. Which in fact they did, for the worse! I didn’t say anything publicly then and moved on. However, seeing the same generalization occurring now, I’d like to stick to the facts and so allow for conclusions to be made without generalizations.

- A VO70 cannot be designed not to break. In fact, any boat in a round the world race cannot be designed not to break. So ultimately, breakages are in the hands of the crew.

- Puma won leg 5 without a major structural problem and this due to the excellence and experience of its crew.

- Telefonica finished 2nd in leg 5 with a hull delamination in port mid bow which did not prevent her from racing.

- Telefonica’s pit stop in Cape Horn was not a necessity but rather a very clever strategical decision based on having 3rd place assured and a weather window to exploit.

- Groupama, notwithstanding of an excellent management of the boat during leg 5 to see misfortune hit them with a broken mast, has sailed on her own means to Brazil without structural problems.

So, while we focus in understanding why there have been so many problems with the rigs, I’d beg not to generalize and avoid putting in the same basket the good work and brilliance of some engineers with that of others which are clearly not the same.