Predictwind release improved racing and cruising routing function

by Richard Gladwell, Sail-World.com NZ on 28 Nov 2016 PredictWind has released a major upgrade to its Routing function, taking a much more graphic and interactive approach to what has been a black art of weather routing, used to choose the fastest route for racers or most comfortable route for cruisers.

The new approach features a 'race' between the various weather models allowing the skipper, navigator, and crew involved in tactics to see the various options played out as the 'boats' race between the two points, and maybe intervening way points. But of course it should be noted that often the fastest course can require some extreme tactical options. In practice, most navigators choose the most direct course of the options and then cover off other weather nuances as they come into play later in the leg.

A good example of this occurs in a race where a deviation from the rhumbline course is justified to pick up tradewinds in the latter stages of the race or cruise. The four Predictwind models will determine the current position of the tradewinds and then show the course options available.

The image above shows the route options for a supermaxi leaving Auckland on Monday evening, heading for Sydney. The optimal route would appear to be the green (GFS model), being the fastest and also most direct. Despite the large variation in recommended routes, there is only 11 hours difference in time taken, but 287nm difference in distance sailed.

It should be noted that the image shows massive differences in the optimal route (except perhaps for the two more direct courses). This scenario is typical for a high performance boat such as a supermaxi or multihull, however the course options across all models are similar for the first day or so. As updated forecast models come in every 12 hours, the models will fall into a more consistent line, usually with the extreme courses becoming more closely aligned with the middle/direct course. But there will usually be an optimal course one side or the other of the direct course to position the boat to take account for incoming weather systems and allow faster speeds towards the end of a leg, for instance.

The usual text readouts are still produced on a second screen allowing the involved crew to check the numbers, see which is the fastest route and by how much.

Predictwind produces its own enhanced models from four weather feeds including the recent addition of the highly regarded (European Centre for Medium-Range Weather Forecasts) ECMWF forecast feed which uses a resolution of 9 km, making it the highest resolution ten day GLOBAL model available. Predictwind believes this global resolution coverage is unprecedented and the super computing power required to run a global model at 9 km resolution is truly impressive.

The four weather models power the Predictwind routing model. Once the overall picture has been reviewed, the course options can be investigated individually by selecting the preferred feed, which shows the fastest route - and then looking at the tactical risks involved overlaid with the wind flows (strength and direction). The wind is displayed using its unique morphing colour effect to show strength and arrows to show direction, rather than the traditional arrows and barbs approach which is much more difficult to assimilate.

As with previous versions, Predictwind's routing uses standard polar, or performance data for a boat type or class. Another key feature with the upgraded function is that the boat's performance profile is somewhat locked, and doesn't need to be set or adjusted each time the application is used. If a standard polar is not available for your boat, then pick one that is close and adjust by using the percentage function. Or you can adjust your class polar depending on whether you think your boat is faster or slower than standard.

This information and settings are retained when you log off, and your updated instance is available on whatever devices you next login to Predictwind - be it on a smartphone (Android or Apple), iPad/tablet, PC or laptop.

Working with a laptop or PC before the race or cruise enables you to see course options and weather/wind data evolve in the days leading up to your race start or departure.

 

About Predictwind:

Developed by former Olympian, Jon Bilger (470, 1992), PredictWind application was used by the Swiss team Alinghi to win the 2003 and 2007 America's Cups, and has become the leading wind system used by racing and recreational sailors around the world. It is available on a subscription basis and also with a free forecast option.

A mobile app for Android and iPhone is available and www.predictwind.com!PredictWind is available for download

Real time local wind observations have been added as further functionality.

You can check the weather anywhere in the world, and get a five-day forecast, plus a variety of other features and functions of www.predictwind.com!PredictWind. The app is synchronised with your PC so that your latest set of locations are always available without resetting each time you change a device