Saturday, November 14, 2015

SeaPilot 3.85 Weather Routing

Application: iPhone, iPad, iPod Touch, Android versions also
Function: Chart Plotter, Routes, Marks, GPS, AIS, Instrument dataRating: *****
Cost: App is free, in app purchases for all features.

I reviewed the previous version of SeaPilot back in November of 2014. Since then their programmers have been busy adding features including a weather routing option.

The new version 3.85 of SeaPilot released in September 2015 has some new features that sailors will enjoy. Weather routing is a very important tool to have when your crossing oceans or a major body of water.  The routing feature will provide you the optimal route to take with the forecasted wind conditions.  SeaPilot uses the wind and current weather related GRIB files and the polar diagrams of your particular boat to provide the best route.  This routing will save you time and get you to your destination sooner.

GRIB files are a gridded binary files that can be downloaded from several weather related sources on the Internet.

These files include a grid display of current and wind strengths and direction. The GRIB forecast data can then be stepped through to see the varying conditions over the next 6 to 12 hours.

Updated forecasts are provided regularly by several weather services around the world so they are readily available. An Internet or satellite connection will be needed to download the most up to date files.

To GRIB files provide the forecast of the wind but the app also needs to know the polar diagram data for your specific vessel to provide the routing information. Polars are a representation of the sailing yachts performance and velocity made good at various sailing angles to the wind. Your sailboat manufacturer should be able to provide this data to you. If not find a boat similar to yours and use that polar data.

There is also an app to calculate your polar diagram data if you can't find a boat similar to yours.  It is called iPolar which I reviewed back in December of 2012 on this blog. This app will help you develop a custom polar diagram for your yacht.

The app requires inputs for your boats length, displacement, length at water line, main, jib and spinnaker sail area. Once those values are in the wind speed can be selected.  The tabular data is listed under the values page. This is the data that the SeaPilot app will need to do your weather routing.

The SeaPilot app weather routing simply provides the fastest route between two points regardless of water depth and shoals. So pay particular attention to depths along the optimized route to make sure the depth is adequate for your vessel.

The routing feature can be acquired with an in-app purchases of $59.70. See all the in app purchases listed on the SeaPilot website.  The weather routing feature also requires that you purchase the Marks, Routes and Past Tracks module for an additional $10 USD. US chart sets will cost you about $10 per set also to track your position and display the routes on NOAA vector charts.

The addition of weather routing to SeaPilot is welcomed but it falls short of the weather routing offered in the Weather 4D Pro and Predict Wind apps.  These apps both provide multiple weather models and multiple routing options. If your serious about looking into weather routing for your yacht, I would check those apps out for sure.

~~~ Sail On ~~~ /)

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