Zezo forum:

Post by bewareth | 2014-02-21 | 08:01:41

For the 1st time I got totaly wrong adwice from Zezo. The leg is on now, on Clipper, I kept on cheking Zezo and suttenly got advised to tac away from fleet to east. I desided to follow this advise!! Lost 500 spots while the 3 hours tac and when I taced back to North I expected to start receiving. I did receive about 60 spots in the next 3-4 relogs and from this point on I am loosing steady. Waching now the routes, it is easy to see how absolutely wrong this tac was and the loss didnt finish yet. I will be loosing the next 10 hours at least, because the change of the weather will give me redused winds in the squere I am, while the rest of leading fleet, fom which I taced away, has entered the next squere as they kept streight North!! Until today all advises from Zezo that I followed was positive resulted or at least not negative. This is the 1st totaly wrong advise ..prooved from the result. I am sailing together with Solaris which has 2 boats. One came with me while the other stuck to streight North route. The difference is huge and will keep on growing at least for next 10 hours. Any idea why this happens???

7 Comments

Post by zezo | 2014-02-21 | 08:50:33

You can't blame the router for changes in the forecast.

Sometimes it sees a wind shift few days ahead which does not materialize.

There are ways to deal with it to some extent if you are doing a real-world routing and have unlimited computing power - stochastic routing and so on, but for a online service with 1-second response time that's not an option.

And then even the best computers, software and scientist in the world can't guarantee you anything. You saw what happened to Thomas Coville and Sodebo.

Post by bewareth | 2014-02-22 | 16:03:30

Thanx for the replay Zezo. From the start the router showed a plan of the race going up north. That change was suttenly and right on the spot. I should be more sceptical as after all is up to ourselfs to decide which route to follow. I show other competitors tacing with me at the time, but some of them after a short distance taced back north (including you). If things were different, racing would loose its interest. I dont blame the router in any case as it has been proved, so many times, a very usefull advisor. The way all that happened it was a bit strange and unusual so I thought to let you know. I must thank you for the excellant work you are doing and for the way you deal with all of us that are using your router

Post by zezo | 2014-02-22 | 17:51:09

This leg had somehow strange strategy so far.

The monsoon turning around Vietnam creates enough shift to make going slightly off the optimum upwind angle worth it in order to get to the better wind faster.

But when the pattern changes for a while router would prefer sailing closer to the Great Circle again.

You are correct that I tacked too, but tacked back quick enough to recover. The reason I'm few miles behind the leading boats is that I don't bother to optimize cell border crossings and all the leading players do.