Doyle Sails

Designed and developed by 360 Maritime Media Robbie Doyle, an America's Cup veteran, Olympian and former Vice President of Hood Sailmakers, founded Doyle Sailmakers in 1982

Robbie's background in Applied Physics from Harvard University further enhanced the young sailmaking company. It was the revolution in the scientific understanding of low speed foils that led to the design of the now famous winged keel. Working with the same Delft University team and flow programs that led to this breakthrough keel, Doyle Sailmakers was able to develop and apply the principal of Elliptical Aerodynamic Loading to sail shapes.

These revolutionary shapes provided almost instant success on the race course, and allowed Doyle customers to post victories in a wide range of venues, including the most demanding Maxi World Champions, 12 Meter World Champions, 50-Foot Cup World Champions. In fact, in every major class right down to Optimist Dinghies, racing sailors had no choice but to take note.

As a result, almost overnight, Doyle Sails grew into a world sailmaking power. The Doyle Sailmaking Group now has 40 lofts, located in 20 countries around the world producing coastal and blue water cruising sails, Kevlar sails, D4 sails, laminated sailcloth sails, pentex sails and woven polyester sails.

Doyle Sails miraculous growth, fueled by racing success, was actually built on the popularity of its carefully refined, often unique cruising sail designs.

Doyle introduced the first radial cut, roller reefing Genoa with a tapered foam flattening device, the QUICKSILVER, in 1983. This was soon followed by the introduction of the fully battened, self stowing, patented STACKPACK mainsails. Most recently Doyle has introduced the SOFT CLEW for big roller furling Genoas and racing mains for rollaway masts.

The SOFTCLEW replaces heavy clew rings with a series of Spectra lines which are safer and more efficient. Doyle sails custom slides convert a roller furling mast to one that can handle a more high performance battened sail. These types of innovations have made Doyle Sails a leader in performance cruising sails as well as racing sails.

Doyle Sails' reputation for impeccable attention to engineering detail, quality of construction and application of the latest technology to cruising sails, has made Doyle the choice of some of the world's most spectacular yachts. Doyle has successfully integrated old-world craftsmanship with fully computerized design and laser cutting. Doyle has built sails for large yachts from traditional tall ships to America's Cup boats.

Doyle Sails has come a long way, but founder Robbie Doyle feels that they are just now at the beginning: "The true power of the tools we have spent years developing are just now being realized. I see sailmaking advancing more in the next few years than it has in the previous 20. That's revolutionary."

THE SAIL DESIGN PROCESS Three dimensional modeling, pressure distribution, stress strain pictorials, laser cutting, wind tunnel testing, and much more all figure into making a modern sail for your boat. The following outline will bring you through some of the steps used in designing sails in the 90’s and beyond.

The first step in any sail design process is to decide on the geometry of the sail needed to fit the boat. All the outside dimensions need to be defined. In most cases this is an easy operation and can be accomplished by directly measuring the boat with a tape measure or consulting a sail plan which is a scale drawing of the boat. Once the size of the sail is confirmed the interesting analysis starts.

The outside dimensions of the sail are entered into a sail design program where a 3 dimensional shape is described. In most cases 3-dimensional shapes are described by horizontal and vertical cross sections of the surface. The key factors in describing these sections are chord depth %, maximum draft position, entry and exit angle, and twist ( the amount of deflection the leech has from a straight line between the clew and head, generally described in degrees).

For most boats the optimal sail shape cannot be applied to the sails because of several obstacles like genoa track locations, spreader lengths and position, headstay sag and mast bend.

For example, if a sailmaker designs genoas for a boat that has long spreaders and does not consider the spreader length when designing the sail it cannot achieve the designed 3-dimensional sail shape the genoa must be trimmed through the top spreader to do so. Since the spreader cannot move the sail cannot be trimmed in, and thus the sail sets with more twist than designed. This one little design flaw causes the sail to set with the following problems, flatter camber than designed, fuller entry to the sail in the upper portion thus, the sail luffs earlier and, wider exit angle decreases the power in the sail.

Once the 3-dimensional sail shape is described the sail is ready for wind tunnel testing. The goal of wind tunnel testing is to optimize the lift and drag ratios for the boat. These coefficients change with the change in 3-dimensional shape. Therefore several models may be made to hone in on exact specifications.

Once an optimum shape is settled upon the sail now enters a purely analytical aspect of the sail design process, finite element analysis and pressure distributions. To get meaningful information from finite element analysis we must consider the properties of the material used to make the sail in addition to the loading on the sail.

Since sailcloth is non-isotropic in it stretch resistance we utilize a polar plot of the materials resistance to stretch, and the placement or alignment of this material in the sail. Since sails are dynamic in their use and do not have one load path that handle all conditions and trim.

The placement and aligment of the material utilized is an important aspect of the optimization process. Therefore the material selected must have ample strength in all directions to handle the dynamic loading. To help us understand these types of loads we generate stress and strain graphs of the sails.

These graphs analyze the sail and allow adjustments to the design or shape of the sail, these adjustments are made to bring the sail into predetermined stress/ strain limits. The output from this process is a loaded 3-D sail shape taking into account initial 3-D shape, material properties and alignment, wind speed and direction. This deformed 3-D shape is then brought back into the design program.

... Stress: F/A, or the load divided by cross sectional area.

... Strain: (Li-Lo)/Lo, or Deformation in length divided by original length.

... Modulus "E" = Stress / Strain, is the slope of the straight line portion of the stress strain diagram..

Once all the analytical work is completed and the 3-D mold of the sail is decided upon and the exact material is selected, the sail can now be broken down into small 2-D pieces and cut out. This is accomplished mathematically with geodesics. A geodesic is the shortest distance between two points on a curve surface.

Similar to a great circle route when crossing and ocean, the same principals apply to the sail surface. The term mould is used in several sail companies. Currently all sails, if designed utilizing a 3-D design program, are mould shapes. No sail material is moulded. All sails today are all constructed with flat plates that are shaped to simulate the 3-D shape.

Doyle New Zealand have once again been first in leading sail design software. For 2 years now Doyle have been utilizing the world leading sail design software "Sailpak", which has the ability to 3 dimensionally model any sail at the actual flying shape onboard the boat, and combined with various sail combinations and settings.

The next generation in saildesign is now available when purchasing sails from Doyle NZ. With Sailpack-Viewer the Doyle sail designer can create a single file (PPK) with all the sails and rig together in an active 3D view.

The customer will be able to see, from any point of view and with multiple options of rendering (geometry, mould aspect, paneling and/or full description with finishing details), his/her personally designed sail. This interactive design information can be made available by CD or downloaded directly to your computer from the link above.

Doyle Grand Prix Racing Sails are designed for boats from 40 to 100 feet that are finished to grand prix racing standards to meet extreme loads and the demands of the serious racing program.

STRATIS™ RACING SAILS

Advanced sail technology for

unsurpassed performance.

Stratis™ combines Doyle’s long standing design expertise with innovative in-house fibre aligned technology. Specialised design and manufacture deliver unsurpassed shape retention and performance throughout the most demanding race conditions.

Stratis™ advanced fibre-aligned sails make load-path technology available to the racer and cruiser racer alike.

Combining world-leading design with innovative engineering and materials technology, Stratis™ sail laminates are custom designed and manufactured to the individual specifications of each sail.

Stratis™ sail laminates are stronger, hold their shape better, with much less stretch and are significantly lighter than conventional panel sails.

Stratis™ sails custom designed, fibre aligned sail technology is now available to all sailors, not just Grand Prix racers.