The North Design Suite is an integrated family of specialized software programs that brings unprecedented power and flexibility to sail and rig analysis. Each specialized program can interface with others within the suite, allowing North sail designers and engineers to virtually sail and test a boat in an infinite variety of conditions before construction. NDS significantly expands a designers ability to test different sail and rig combinations and accurately measure results. Equally as important, NDS significantly reduces tuning and development time after launch.
Precise control over all aspects of a sail's shape allows a broad range of mainsails, genoas, jibs and asymmetric spinnakers to be designed.
Every dimensional aspect of the sail can be adjusted both in horizontal and vertical axes.
Desman creates a complete rig/sail model in a three-dimensional environment.
In Desman, North designers can specify mast size, rigging position, rigging attachment points at the deck and trimming locations.
The modeled sail/rig system incorporates the mechanical properties of the spars, standing rigging, running rigging and sails in terms of moments of inertia, sail and spar surface area, materials stiffness and resistance to stretch.
Later in the process, Membrain (described later) uses the Desman model to determine deformation under load for the sail and every piece of standing and running rigging, right down to stretch in the sheets and halyards.
3D Layout is used to define the structure of a sail in terms of yarn layouts, panel layouts, tape layouts, yarn density, and/or film types.
Output from 3D Layout is used to shape 3DL molds or provide seam curves for paneled sails.
All yarns are plotted in the same 3-dimensional space they will assume when sailing.
3D shapes are translated into panel layouts for downwind sails.
3D Layout also has powerful analytical tools which can be used independently or in conjunction with Membrain.
Using Flow, wind pressure is introduced over the sail's three-dimensional “mold” to produce a pressure field on the sail's surface.
The pressure varies over the surfaces based on the size and shape of the sail and the strength and direction of the air flow.
The resulting pressure field is then linked directly to Membrain for finite element analysis.
Flow also reports the drive and moments developed by sails, which can later be used by either the North Sails VPP or other VPPs for sail performance analysis.
Membrain takes the sail/rig model from Desman and applies pressure fields from Flow, deforming the mast and sail as a single unified structure.
As the sail/rig structure is deformed, the shape of the sail changes, so Membrain then links back to Flow to acquire new pressure fields for the deformed surface.
This changes the sail shape in Membrain yet again, so the process is repeated until there is stable balance between pressure and rig/sail deformation.
Membrain can be used to test sail shapes, optimize mast design and rig tune, create sail shapes to test in North VPP, check loads for designers, and more.
SailScan II analyzes photographs of sail shapes taken on-the-water and then compares these shapes to the original design file.
SailScan II is a valuable tool for determining if a sail needs shape adjustments after a specific period of time.
It also aids North sail engineers and production specialists in refining production and simulation methods toward improving the competitive life of North sails.
Virtual Wind Tunnel (VWT), was originally developed jointly by Dartmouth College Thayer School of Engineering and North Sails and is now run by the Stevens Institute of Technology.
VWT is the first (and still the only) computer simulator to accurately model wind flow on downwind sails at 100% scale.
When first developed, North Sails used the world's two leading low-speed wind tunnels (University of Auckland Twisted Flow Wind Tunnel and Oracle's IACC Twisted Flow Wind Tunnel) to verify it's accuracy.
The results have given us great confidence that North's “VWT” predicts results with more accuracy than wind tunnel sail testing of any kind.
VWT provides powerful insight into flying sail shape, sail drive, shape stability and ease of trim.
Unique to VWT is its ability to integrate with Membrain allowing both upwind and downwind sail shapes to be analyzed with unprecedented accuracy.
Understanding how adjustments in sail shape affect speed is only part of optimizing a boat's performance.
Race Model allows North designers to account for changes in rating from one test configuration to another. The Race Model can predict which configuration will win in a handicap race over various courses.
SPP (Sail Performance Prediction) is used to predict relative sail performance between different sail designs or trims quickly.
Using SPP, designers can instantly compare the performance of a new sail design relative to a baseline mold. This allows a designer to test up to 10x the number of shapes compared to running individual designs through a large matrix of runs in Flow then coupling these results into the VPP.
Additionally the SPP can be used in cases where the sail designer was not able to acquire enough data to run the North VPP.
Router takes a boat's polars and combines them with a historical or predicted weather file and races the boat between the start and finish of a leg.
Changes can be made to the boat's configuration allowing North designers to predict the fastest configuration for a specific race.
This tool was initially developed by Michael Richelson of North Sails for the Illbruck Volvo Ocean Race Team.
Das Boot is one of the most powerful free surface Hydro CFD programs in the world.
Das Boot is a Potential Flow, Free Surface Code used for sail and rig development for America's Cup teams, TP52s and Volvo Ocean Racers.
The results from Das Boot are used to generate hydro resistance files for the North Sails VPP.
Sail Compare allows North Designers to compare sail shapes between on-the-water sail photos with Membrain-predicted shapes or between two different Membrain sail shape tests.
It is used to refine North's software tools allowing North Designers to more accurately match customer requirements.
A good Sail Selection Chart is like an owner's manual for your sail inventory.
Every sail is going to have its sweet spot, and when racing offshore or in coastal races it is critical to know the True Wind Speed (TWS) and the True Wind Angle (TWA) of the next leg and have your crew prepared to have the next sail ready to hoist at the mark.
Even more critical is making sure the right sail goes up when you round the mark saving costly sail changes.
North's VPP and Hull VPP are powerful new tools that allow hull/appendage data to be integrated with rig/sail models, giving designers the ability to analyze an entire sailboat, from masthead to the tip of the keel, as a single working system. Both programs use sophisticated CFD modeling to develop reliable hydrodynamic hull data without tank testing.
Hull VPPTM can be used to create a set of hydrodynamic forces for a specific hull & appendages, then feeds this information directly to North's VPP. This is accomplished by providing Hull VPP information as an IGS file (3D surface file of the canoe body and appendages).
Once hydrodynamic forces are established for a specific hull, aerodynamic sail data for the same boat's rig are generated by Flow & Membrain (and now the VWT) and then integrated into the VPP process.
All upwind aerodynamic sail forces are derived from a specific yacht's custom sail designs as predicted by Flow/Membrain, as opposed to generic sail force coefficients used in other VPP processes. Reaching and downwind cases have the option to use specific sail force coefficients developed through North's Virtual Wind Tunnel runs, or with custom coefficients that would be developed with the VWT.
In addition, North VPP can be used to optimize sail shape and/or sizes to suit a rating rule or a specified set of wind and sea conditions.
As a result, upwind sails refinements can be tailored to the specific boats characteristic and downwind sail codes and areas can be chosen based on specific goals. These tools represent a significant technological leap forward, allowing North to accurately tailor sails for any boat and introduce design advances to a broader spectrum .