Ever sat there waiting for the grib to arrive? Want the grib on your computer ready to use? I’ve written a Java utility that will monitor the SOL server and automatically download the grib file for you when it arrives. It’s been enhanced to include a DC editor and now has a graphical interface. Continue reading Automatic Grib Downloader and DC Editor
Category Archives: Sailonline.org technical stuff
About things like mark roundings, performance loss and DC setting techniques. About anything that’s only on sailonline.org
Bi-Linear and Linear Interpolators For Excel
Want to work out your performance loss for a tack / gybe or expected boat speed from TWS and TWA in Excel. Then you need to have a look at this. Continue reading Bi-Linear and Linear Interpolators For Excel
Around the Bend on the Bay of Biscay

At first glance, this race looked to be a simple reach up the coast. At least that is how it would be if the initial winds held.
Yes, there was an island to deal with near the finish. But odds were we would leave the island to starboard — problem solved. This race seemed to be routine.
But as the ‘Mad Russian‘ character from Jack Benny’s radio show would have said, “Silly Boy!” The race was far from routine.
Cancelling a command
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.
Sailonline Performance Calculator
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.
Exploring SPINNACER 1.1
SPINNACER (SOL Polar Inspector, Nautical Navigator And Calculator to Enhance Racing) is a java program that should help its users understand the polars (as used by sailonline.org) better, and performing (more accurate) calculations, e.g. for setting DCs. The “NN” part in SPINNACER is still in development, polar inspector and calculator are available