New Boat 4 Sled

[sleddog]

I don't know how many of the SHTP fleet are using routing programs aboard for predicting their future course to Kauai. Routing programs can vary from free to expensive. Their suggested route is predicated on "GRIB" files, showing anticipated future wind direction and strength cross referenced to the boat's "polars."

Their are some issues with routing that are easy to overlook but very important. The first is "polars" are generated for fully crewed boats sailing at 100% of their potential. When I attempt to use a routing program when singlehanding, I have to make my own polars, as most boats in the singlehanded fleet don't have commercially available polars that take into account sailing solo on a "bring what you got" boat that might be 40 years old.

Another method might be "borrowing" polars from a boat similar in characteristics/speed, and then "dialing" in a correction to your routing program. For example, using a J-105's polars and dialing them back to 85% for an O-30..

Another issue of routing to Hawaii is mentioned by Stan Honey, who cryptically writes "a Router will take you too far North. Understand why. Still useful."

If we understand Stan's caveat, he means a routing program like Expedition will take you the shortest, fastest course, which is right on the southern edge of the Pacific High. Kinda like walking on a cliff edge. If you get any further north, you fall off the cliff and into the Pacific High.

Looking at the 48 hour forecast below, there is definitely a cliff to fall off north of 30 degrees N. latitude, west of 135 W. if the barometer gets higher than 1023 mb. Why I prefer CRINAN's southerly position to RIFF RIDER's, further north.



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