SailFast LLC Marblehead-Halifax Race Software

SailFast Overview

SailFast™ is a PC-based navigation program used to predict optimum routes for offshore racing and cruising. Weather information is imported directly from Grib forecasts of wind, current and sea level pressure. Built-in Gulf of Maine tidal currents are already included.

Taking into account vessel speed characteristics and predicted wind and current, SailFast™ determines the fastest course from start to finish, or between any 2 waypoints. “Isochron” methods are used to find a globally optimized route. A typical isochron solution from start to finish takes about 3-5 minutes to compute.

SailFast ™ predicts vessel speed using standard polar diagram information. A scalable generic polar diagram is also included which may be used when the skipper does not have polars for his boat. Various “what-if” capabilities are included to allow the navigator to explore course and weather alternatives. SailFast is a powerful tool to assist with the tactical and strategic decisions that win or lose races.

Globally optimized routing using isochron methods

Import predicted 10 meter wind and mean sea level pressure using free Grib weather forecast files

Detailed tidal currents for the Gulf of Maine

World wide base map

Use Grib files with current data, such as the Gulf Stream

Use a built in scalable generic polar diagram or input custom polars for your boat

Powerful what-if functions for wind and course variations

Detailed navigational data for every segment of the fastest track solution

NMEA 0183 interface to GPS and wind instrument data

Windows Vista compatible - System requirements

Compare to alternatives costing 5 –10x more

Gulf of Maine Currents

SailFast includes detailed tidal current information over the majority of the race course. Current speed and direction is given at an array of locations, and is available in hourly increments referenced to high and low tide. As SailFast simulates sailing along a track, it interpolates the tidal data to find the predicted current for the simulated location and date/time. Arrows are displayed on the chart that represents the current vector. The color and length of each arrow is an indication of the current velocity. As SailFast moves along a simulated track the current arrows are updated dynamically allowing the navigator to quickly get an appreciation of the effect that current has on the boat over time.

Note that even when Grib forecasts of surface current are available, the time interval between forecasts is often too large to be of much use for modeling tidal current.

Below is an example of current in the area of Cape Sable and Brazil Rock. The values of predicted current direction and speed can be displayed by positioning the mouse at any location on the chart.

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World Wide Base Map

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Polar Diagrams

SailFast includes a default polar diagram and accepts custom polar diagram data that may be provided by the user.

The default polar is for a 38 foot mast head sloop racer/cruiser with asymmetrical spinnaker. A table shows predicted ideal boat speed for specific true wind angles relative to the bow at various wind speeds. The same information is also presented in a graphical polar diagram. SailFast interpolates the data in the table to give the expected boat speed for any wind condition.

If you cannot obtain polars for your boat one alternative is to use the default polar and to simply scale the boat speed to match your boat. While you can get good matching at a particular wind speed and angle, expect errors at other points of sail. For boats of different styles with different pointing characteristics and sail complements, the errors using this approach will be greater. You can also do on the water tests to develop or refine your polars. How can I get polars for my boat?

Six sample polars are included with SailFast.

polar plot

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“What-if” Scenarios

Since Grib wind predictions are never perfect, the prudent navigator will simulate other wind conditions to develop an overall strategy. This will be repeated many times over the course of a race.

SailFast lets you replace the Grib wind at the beginning or end of a simulation, or for the entire race. If the Grib data ends before the simulated race ends you can either extend the last available prediction or specify your own wind. At the start of the simulation you can also use the actual true wind as sensed by your connected wind instrument in place of Grib data.

Another powerful feature is to be able to change Grib wind strength and/or make it back or veer from predicted values. Additional what-if settings can be made for current.

Finally you can adjust the course sailing boundaries to force alternative routing. See examples for navigating past Brazil Rock or sailing through the Gulf Stream to Bermuda.

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Detailed Track Information

After an optimized route simulation is completed the isochrones (blue lines) and the fastest route (green line) are displayed. Your may step along the fastest track and observe the pertinent data for each segment of the track in the left hand data table.

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System Requirements

SailFast is compatible with Windows 2000 and later operating systems. It has been developed and tested with Windows XP and Windows Vista.

The minimum recommended hardware requirements are:

Pentium4 1 GHz

512 Mbytes RAM

250 Mbytes free disk space

CD-ROM (or other means to install program files)

Generally any PC with adequate speed and memory resources for Vista are sufficient to run the program.

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