Ocean Racing Magazine - #6 - December 2007 & January 2008 - (Page 47)

CLIPS, LIONEL LEMONCHOIS’S MINI TRANSAT BOAT IN 1989 (11th) was the first prototype designed by Marc Lombard, who repeated his collaboration with the future winner of the Route du Rhum, in 1995 with n°417 (Les Jeudis du Port), which finished fourth. From this second generation there came QDS (2nd in 2001 with Simon Curwen), then a third boat with Bon Pied-Bon Œil (2nd in 2003 with Richard Mérigeaux) and Aquatec/Opensea (3rd in 2003 and 2nd in 2005 with Alex Pella) before we reach the winner from 2007, Actual (n°624). "In a Mini Transat, changes in hulls are not very striking, because the beam remains the same to within a few centimetres, even on the waterline. The degree of power is therefore similar, which is logical as the mast height, the draught and the maximum beam at deck level have been fixed since 1994. On the other hand, the distribution of volume has changed as the maximum beam on the waterline has moved backwards and there are greater volumes at the stern, which represents a slight increase in power." In fact, when the single-handed yachtsman moves weight around (more than 150 kg), this enables him to modify significantly the hull that is immersed, which becomes narrow at the bow and wider at the stern. By placing the weight in the bow in light airs, this reduces significantly the surface area under the water, and by loading up at the stern in a downwind breeze, the boat’s trim is adjusted to raise the forefoot. This change in hull design has affected both the Class 40 and IMOCA monohulls. No more hollow at the front and straight lines at the back, which makes it easier for the boat to glide along and improves her passage in the water. In fact, according to Marc Lombard, the gains that have been achieved since 1989 essentially concern the weight of the equipment taken on board by the sailor (batteries, solar panels, food, ropes, chandlery…), the rig mass and therefore lighter ballast (around 150 kg in all), added to an increase in the sail area (square topped sail, Code 0, asymmetrical spinnaker…) and a slight increase in power because of a wider beam at the stern (chine). "The biggest changes concern the appendages since the arrival of canting keels in 1991: the keel blade has become a bulb carrier, and the shape has been worked on. However, the weight saved in recent years (which is not that great: see table) is essentially the result of the arrival of carbon masts, which have enabled reductions to be made in the weight of the ballast by around 60 kg over the years. Then there are the large squaretopped sails, which have increased the sail surface at the head…" The Mini rules are in fact very well drawn up according to the designer from La Rochelle, as boats, which are ten years old still remain competitive: the potential of the new prototypes has not advanced very much and it is still the sailor, who makes all the difference. The loophole in the rules, which allows the height of the mast to be reduced to move to head rigging to satisfy stability rules by reducing the weight of the ballast, is no easy matter. Firstly, because that reduces the sail surface by several square metres, Moving weights around Changes in the past and the future? and also because a sail plan is more efficient, when it is longer. The weight saving does not seem to make up for the loss in sail power. "In the same way, we were not convinced about wing masts, following wind tunnel tests in 1999: with the same heel moment, a wing mast has a tiny advantage of between 60° and 90° to the wind, but apart from that it loses out in terms of the finesse of the rigging. The aerodynamic gain has not been proven, especially on a Mini, where the profile is very important, because the tube must hold up structurally. The advantage is rather with the manoeuvres, which makes it more interesting for a larger boat sailed single-handed as in the Vendée Globe. On the other hand, the ability to take advantage of the mast angle is important in terms of the balance at the helm, but that requires close attention to trimming and manoeuvres: this is a route that we shall be going down in the future, as it is more efficient than moving the keel lengthways, as that is very complicated and time-consuming to develop." With canting keels adopted in 1991, the fact that you can add ballast as well as using the keel remains a thorny issue for the designer of Actual, in terms of VPP (Velocity Prediction Programmes). In fact, the ballast acts more on the trim and the behaviour at sea than on the power. When you increase the weight, the power increases… but the drag too. Today, everyone is attempting to reduce the braking, rather than increasing the power: a lighter boat is always easier to handle, especially when we are talking about 60-footers! Marc Lombard has designed a boat without ballast (Opensea), which proved to be just as quick as her sistership with ballast… In fact the tanks of salt water have been moved to the centre to gain in inertia in heavy seas. The changes in Lombard Mini hulls from 1989 to 2007 (Clips : 1989 - Sampaquita : 1999 - Opensea : 2003 - Actual : 2007)

Table of Contents for the Digital Edition of Ocean Racing Magazine - #6 - December 2007 & January 2008

Cover
Edito
Contents
What they said
News
Portfolio - The news in the picture
Transat Jacques Vabre - Monohulls in power
In the words of the skipper - Michel Desjoyaux, A little bit more
Barcelona World Race - A couple sailing around the world
Imoca - Growth crisis in the Imoca class
Transat 6.5 - A whole series of records
Mini Class - Anatomy of a winner
Multihulls - What sort of trimarans tomorrow ?
Volvo Ocean Race - Second generation
Trials - Mach 45 : an unusual IRC
Match Racing - King Richard
Tactics - A good start
Portrait - Jacques Caraës
Lab - Tubular or wing mast ?
Forty years ago - Chichester, the lonely sea and the sky
Equipment - Shop window
New products - From the drawing board to the boatyard
Opinion - The mirage of worshipping technology

Ocean Racing Magazine - #6 - December 2007 & January 2008