Zezo forum:

Post by bevvy | 2019-11-20 | 07:03:50

Hi, All,
A friend is actually racing the RORC Transat starting this weekend. Is there a way I can plug in his own polars and help route him?
Or is it best to just stick with the inbuilt polars?
Cheers,
Ed

7 Comments

Post by zezo | 2019-11-20 | 10:19:00

(also answered by email, but it's interesting question, so posting it here too)

It can be done, but:

One problem is the VR polars are quite detailed - a point every 2 knots
and 5 degrees. Typical boat polars have much less points, and I don't
have a smooth interpolation tool ready.

Second, looking at the current forecast, there is the typical
North-South route split, but the North route is heading straight into a
low pressure system, and you probably don't want to be there in real
life. This router does not account for waves.

BTW I also know someone with a Class 40 in real life, but he's not racing offshore.

Post by bevvy | 2019-11-20 | 12:09:50

Thanks for the reply, I don't suppose you have a setup which is similar to a JPK 10.10? Already built in?

Post by YourMomSA | 2019-11-20 | 14:08:28

FWIW... Any routing advice from ashore would have to be pre-start. Communicating routing recommendations after the start would be a violation of race rules.

Post by zezo | 2019-11-20 | 19:25:44

Rule 41(c) is replaced by:
"A boat shall not receive help from any outside source, except (c) help
in the form of information which is freely available to all boats, which
shall include navigational, weather, tide or current information from any
source which is available to all boats whether or not by payment of a fee
or subscription, but shall not include information gathered or the subject
of interpretation by, or any advice received from, any source not on board
the boat and which is specific to the boat and her situation."

By way of an example and interpretation, downloading charts, weather
and/or tidal GRIB files from subscription services, or having such
information passed to the boat in its pure form, is permitted but
receiving messages or information which is the result of interpretation
as it applies to the boat is not permitted

Post by DonJuan21 | 2019-11-20 | 16:06:30

chromium works for me. It's the base browser code that chrome is built upon without all the google bloat.

Post by BooBill | 2019-11-21 | 02:05:39

With the highest respect for what Cvetan has done for us here, but, Zezo is highly optimized to route fake boats in VR. VR does not account for wave height and direction, currents and ignores TSS. Those are all things that can kill you in real life.

If you want to help route your friend, https://fastseas.com/ gives you 5 free routings per month. It accounts for currents and allows you to set max sustained and peak wind on various points of sail. I think it's only $10 for a subscription, which gives unlimited routings and will even deliver them as a KML file by email. I certainly hope your friend has a Sat phone on board for that. Here's a source of polars for a JPK 10.10, https://jieter.github.io/orc-data/site/?#FRA/FRA38013.

Sorry if this sounds like an ad for Fastseas (I'm in no way affiliated with them), it's just what I used when I started VR, until I discovered this wonderful site.

Post by zezo | 2019-11-21 | 09:26:03

Yep. This router will happily lead you in the eye of a hurricane. It's one of the reasons I'm not trying to promote it for real world use.

The other is that GFS is too low-res for coastal navigation, and better weather data is quite expensive. Like $100000/year expensive.