Performance analysis

Prediction and optimisation of sailboat performance is at the heart of CRAIN know-how, helping sailboat designers to :

• Study, design and optimise hull and appendage shapes
• Study, design and optimise sail plans
• Study of boat behaviour parameters as longitudinal trim, yaw, heel
• Velocity prediction

For fifteen years, CRAIN has developed and confirmed numerical and experimental tools specifically adapted to sailboat studies. Its involvement in the most demanding race projects over the years guarantees quality tools and methods.

• Parametrics formulas
• CFD for hull and appendages (potential or viscous flow)
• Tank testing
• Wind tunnel test for appendages
• CFD for sails
• Wind tunnel test for sail plan and rig

Hydrodynamic and aerodynamic studies of the different parts of the boat provide the designer with useful quantitative and qualitative information for analysis and optimisation.

Exploitation of results is made possible by performance prediction software V2P, used and continuously developed by CRAIN since 1987.

Through the many studies carried out by CRAIN for designers, project manager, sailmakers and shipyards, CRAIN has the flexibility which allows it to propose the most adaptative approach to project targets, schedules and cost constraints.

CRAIN has gathered unmatched experience through various projects :

• Cruising monohulls and multihulls
• Oceanic and day racing multilhulls
• Oceanic open monohull
• IOR and IMS monohull
• IACC boats
• Megayachts and megaraces
• Hydrofoiler and speed record sailboat

This experience allows CRAIN to :

• Guarantee safe and comfortable behaviour of the sailboat (heel, balance, sail handling)
• Optimise parameters of the project

Customers include

• Andrieu Yacht Design
• Philippe Briand Yacht Design
• Groupe Finot
• Juan Yacht Design
• Marc Lombard Architecture Navale
• Gilles Ollier Design Team
• Nigel Irens Design
• Van Peteghem Lauriot Prevost Yacht Design
• Simonis Voogd Design B.V.
• Berret Racoupeau Yacht Design

Reference projects

2001 FUJIFILM 60’ ORMA trimaran, ORMA 2002 Champion, designer Nigel Irens-Marc Lombard-Fuji Design team, skipper Loick Peyron

Fastest boat in ORMA 2002 circuit

• CFD optimisation of sailplan span
• longitudinal sailing trim study and yaw balance with curved foils
• performance prediction

2000 CLUB MEDITERANEE and 110' sister-ship catamarans THE RACE winner and round the world record holder, designer Gilles Ollier Design Team, skipper Grant Dalton

• tank test for hull and appendages
• dynamic trim study based on REVA computations and tank test results
• appendage design (shape, location)
• yaw balance study for various sail plans
• performance prediction and sail plan range

During this project, CRAIN perfected a tank test procedure, including model building adapted to narrow and fast hulls. CRAIN obtained experimental data about this kind of hull (leeway influence, daggerboard efficiency and trim momentum) to validate drag models used in V2P.

One of the original objectives of this study was to get a safe longitudinal trim at high speed. We have used CFD Reva computation to find out shape parameters that influence longitudinal sailing trim.

1999-2000 BANQUE POPULAIRE 60’ ORMA trimaran ORMA, second in Route du Rhum 2002, designer Marc Lombard, skipper Lalou Roucayrol

Launch of curved foils and trim tab on centreboard on ORMA circuit

• CFD optimization of curved foils
• CFD computation of hulls
• performance prediction and helm balance prediction using various sailplan configurations

This project was CRAIN's first CFD application to the multihulls problem. CFD using REVA has been used to optimise hull shape with a particular focus on longitudinal sailing trim.

With regards to appendages, CRAIN has underlined the effect of free surface on foil efficiency. This discovery lead Marc Lombard to design the first curved foils for an ORMA multihull. For the second boat, CRIAIN has optimised the curved foil concept in order to decrease wave resistance. The helm balance study allowed V2P validation for such a complex configuration.

2000 SIXIEME SENS IACC monohull, designer Yaka Design Team, skipper Bertrand Pacé, Louis Vuitton Cup 2000 semi finalist

Designed with a small budget by Yaka Design Team (co-ordinated by Philippe Pallu de la Barrière, manager of CRAIN) this narrow hull with an uncommon shape showed surprising downwind speed and great performance improvement throughout the competition.

The design has been mainly based on REVA CFD and on performance prediction carried out at CRAIN.

1998 SILL 60’ IMOCA monohull, Third Vendée Globe Challenge 2000, IMOCA 2001 & 2002 champion, designer Marc Lombard, skipper Roland Jourdain.

The hull and appendages comes from a conception method that use Reva CFD (Similar to Whirlpool). With particuliar focus on wave resistance reduction when heeling, canting keel and asymmetric daggerboards optimisation. V2P allowed CRAIN to evaluate the interest of wing masts compared to standard masts and to optimize hull width on the Vendée Globe course.

1997 KHAMSIN 40' catamaran, designer Jo Richards, owner Alain Golaz, Bol d’Or 1996 winner

For this overpowered catamaran, optimized for Lac Léman light winds, we have designed appendages in order to go up on one hull from 4 knots of wind speed. V2P has allowed us to provide to the crew, for each sailing condition, sail to use, daggerboard trim, crew location on wings and watter ballast level.

1995 MARICHA 3 : 130’ monohull North Atlantic record (in its class), designer P. Briand

• towing tank test for hull and appendages
• REVA CFD for hull and appendages
• helm balance based on tank test results and wind tunnel result
• performance and sail plan prediction

One of the main concern of the designer was helm balance with a ketch configuration and various sailplans. V2P has allowed to combine tank test and wind tunnel results to get a good balance in any condition