Here I’m going to outline the fundamental principles how I tackle WX routing. Honestly my approach is entirely intuition (or software of course), so I don’t have a strict formal way… but the basics are very true.
1. The rhumbline
The shortest distance between two points is a line. Point at your waypoint, go max VMG if needed.Pros: you get to your destination eventually.
It’s the shortest route, sort of.
Sometimes the fastest route, if only by accident.
This was spawned off the ‘sailors with routers’ debate, I will try to create a comprehensive guide of what goes into a successful SOL race.
I will start with a review of fundamental routing strategies. Explaining VMC and it’s applications is going to be the meat of this guide.
It happens sometimes. You click the “change course” button and directly after, you see you made an error. You forgot to check the “delay” box, entered a wrong number or entered a TWA in the COG box. If you’re quick you might still be able to keep the command from executing, and continue without performance loss.
The first “winter” storm has already travelled south from the Gulf of Alaska and brought rain to the Pacific Northwest and down into Northern California. Three more storms are making their way west across the Pacific. But reaching those winds may take some doing.
Continue reading 'Gray Whale Migration — pre-race'
The third in the 2014 series of SSANZ races in the Hauraki Gulf began as a beat to wind’ard in light airs. It quickly turned into a match race.
The forecast was for winds backing from 88°T to 84°T during the beat. That favored sailing the left side of the course. And that meant tacking along Rangitoto Island.
At start time, a Low Pressure system is moving east across North Island − crossing the coast at Hokianga Harbour, about 100nm NW of Auckland.
This weather system will determine the winds (TWS and TWD) for the fleet throughout the race.
An initial wind forecast of 6 kts out of the east dictates an on-the-wind start. The sail remains a beat to wind’ard until past the initial Motutapu S mark and into the Motuihe Channel.
When WINSTON rounded The Cows and headed for the finish line at the end of The Vineyard race I smiled.
WINSTON was headed for the line at an angle.
I was going to do the same thing.
Instead of taking the shortest route to the finish, we were taking the quickest route.
It’s all about VMC
The calculations in sailonline’s performance loss system are a bit complicated. Sometimes it’s really handy to know how much you will lose as the result of some manoeuvre. This is why I made the Sailonline Performance Calculator.
In this race, there are three reasons to head up the east coast of the United States and Canada.
First, the Great Circle Route goes that way. Despite appearances, the Rhumb Line on Chart #1 is about 165 nm longer than the Great Circle Route arcing to the north side of the rhumb.
But second, and more important, is the Bermuda High.