Day 3 to NZ – So THAT Wasn’t in the GRIB File!

Distance to go: 694 NM

GRIB File: Short for “Gridded Binary”, these are the files that contain weather data that sailors download to predict future weather. There are several sources of them, but the most common are the “GFS” model and the “Euro” model, representing the source of the weather prediction model that is used in the file.

Evenstar has tools for numerous sorts of weather information available to us in order to predict what to expect on a trip. Our plotting software, Maxsea, has an excellent “Routing” tool that is sophisticated enough to provide a rough expectation on what weather conditions, expectations and trends to expect along a given route at a given time. These predictions would probably prove quite adequate if the GRIB files I downloaded for it had any bearing on reality.

Yesterday was a good example. Based on the latest GRIB file I downloaded an hour before we left Savsavu we were to expect light conditions for the first couple of days. Some sailing, but Thursday and Friday would have little to no wind. Come late Saturday some wind from the S to SE was expected, in the range of 15-17 knots, which would swing East over Saturday evening to provide some comfortable reaching through Monday where the winds would die out and mostly disappear for the rest of the trip.

Nothing about DUE SOUTH winds. Nothing about 25+ knots, gusting to 30.

Backing to to where you left us yesterday, we were hove to and looking to see how this abrupt shift in weather would pan out.

Keep in mind we were NOT sitting this out for the wind strength, 25 knots isn’t dangerous in a boat like Evenstar. From the right direction twenty-five knots is an absolute blast – you just hang on tight and go like hell.

We were looking for a shift in direction. While twenty-five knots on the nose isn’t dangerous at all, it is annoying as all get out. Sailing as high upwind as we can requires a human driver. We were looking for the wind to clock a little to the East, which would let us “crack off” about 10-15 degrees from upwind beating and allow the autopilot to do it’s job without exhausting us.

So we hung out for a while, took some naps, had some dinner. After about four or five hours of this the wind had indeed moved to the East (or “to the left” since we were heading South) and we could carry sails and use the autopilot on a course that would actually hit New Zealand at some point instead of New Caledonia.

So with sails reefed the the Fun Meter (or “Wind Speed Indicator”) pegged around thirty knots we started sailing again. It was kind of a wild, lumpy night, but we made decent forward progress. By morning the wind has eased a bit into the low to mid twenties. When I took over again at 0600 the wind was light enough that our reefed sails were too small. So I eased the sails, shook out the reefs, and we speed up again and have been maintaining seven and a half knots or so on a close reach every since.

According to my GRIB file, however, the wind should still be flat and I should expect it to gradually increase to fifteen knots around eight o’clock this evening. So I’ll keep an eye out for when it starts to drop.

Related Posts Plugin for WordPress, Blogger...
This entry was posted in New Zealand, passages. Bookmark the permalink. Follow any comments here with the RSS feed for this post. Post a comment or leave a trackback: Trackback URL.

One Comment

  1. Hope the wind changes and you get here soon! However if you do end up in New Caledonia, its all good! We sailed up there this year and it was fantastic. Loved it.

Leave a Reply

Your email address will not be published. Required fields are marked *