Routing for Non-Routers

17 10 2009

I’ve been sailing virtual races with http://www.sailonline.org for a couple of months now, and have had a great time learning (and re-learning) what makes for a fast route. The techniques obviously apply to modern offshore racing, where most of the winning margins are now decided on weather decisions, but apply equally to inshore competition and round-the-buoys Wednesday night club races. Cruising sailors benefit as well, particularly on long passages – though you’ll often base decisions on safety, comfort and ease of sailing over outright speed…

An ongoing discussion in the chat on sailonline is the issue of software routing solutions. Among the “sail-by-feel” fleet, there exists a school of thought that holds that any “math” based assistance is outright cheating, while many others value the “near-perfect” solution presented by the top-tier router boats as a standard against which they can compare their own performance. There is a whole spectrum of opinions in between and indeed the determination of what consists a software-based solution is anything but clear cut. What is undoubtedly true is that winning on SOL requires hard work, a fair amount of time, and a healthy dollop of luck.

My own progression was  as follows:

  • Raced using only the on-screen polar
  • Discovered the VMG feedback in the polar window (aha! that is how everyone is picking the same angle off the start…)
  • Transferred the polar into excel so that I could see it better (found brainaid’s website with polar data)
  • Traced the polar onto paper so that I could hold it up to the monitor in an attempt to figure VMC on reaches
  • Played a bit with SailPlanner – tried to figure out what it’s doing
  • Generated massive pile of scrap paper with hand calculations
  • Rewrote the spreadsheet to include VMC calculations
  • Reworked the spreadsheets to produce printed polars with VMC info
  • Wrote custom software

The point all along was to learn as much as possible, and writing my own tools is one of the ways I learn best. I don’t think that the situation of routed vs non-routed boats is quite as dire as some seem to think though, and based on what I’ve learned, I’m pretty confident that on most races, a boat using only a decent polar can compete with and beat all but the very best of the routed boats, of which there are only a tiny handful. That’s no math… not even using a spreadsheet, which although it might give slightly “more precise” numbers, will often give you the wrong ones if you aren’t careful…

These pages will be a work-in-progress attempt to get some of the ideas I’ve been working with down, and available for discussion. The ultimate goal is a set of tutorials that I hope will be useful to interested boats on sailonline and sailors everywhere.

76Trombones


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3 responses

29 10 2009
Routing for Non-Routers | BLUR

[…] Routing for Non-Routers […]

29 11 2009
Aklinyolu1

76trombones, all this information about navigation… great work!

14 03 2011
WhyNot

Great stuff. My progression is similar to yours, except I didn’t know about the VMG feedback until I read it here. Thanks.

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