When V-Sailing on Sailonline.org, it is quite important to have your PC clock in sync with the SOL server. Everything on the map that requires a time (the wind, predictor etc) will not be quite right if your clock is out.
Imagine, your clock is 3 minutes fast. You are on a COG course heading for the mark 2h02m out. You decide to set a DC to round the mark, and do so by waiting until the 2 hour ‘pip’ on your predictor just passes the mark before you hit send, with a delay of 2h 0m (or 2.0) set….
If the wind is increasing at the time you Send, you will very likely turn before the mark!! With a clock 5 minutes fast it is almost certain…
Other artifacts of being out of sync with the SOL server clock (which is kept up to date with atomic clocks using the NTP) include inaccurate display of wind data when you hover the mouse over an area of the map, and the predictor itself will not be quite right (because of bad wind data). Think of it like this, if the instrument panel tells you the current TWS is 15.1kn, and you hover the mouse over your boat, and in the map top right corner it says ‘14.95kn’, well, it is the 14.95kn that is used as the starting winds in computing the predictor, and every segment of the predictor will be similarly inaccurate… Things only get worse when the wind is also shifting significantly.
This probably explains many a SOLer missing a mark when using a DC, or hitting land when on a TWA course.
Here I present a small tool, written in Java so able to be run on any PC with Java installed, that queries an NTP server (there are 20 preset included, or you can specify any one you like), and tells you how much (and which way) your PC clock needs to be adjusted. It also displays a text clock, to allow you to open up your System ‘change date & time’ settings, set the time 10 seconds ahead, and click ‘Apply’ when the 2 times match.
While any NTP server on the planet will do (so any server in the list of presets), it is best to choose one close to your location.
Below are 3 images. The first showing usage with a preset Server with my clock slow (it shows I need to adjust by ‘+51s). The second, I input a server from my own city and my clock is fast. The 3rd is after I corrected my PC clock (just by setting it a few seconds ahead, and waiting until the display on the app caught up and clicking ‘Apply’) – so you can see I get it to needing 0 seconds modification….
Just for fun (and for the techies) I wrote it to output some technical information gathered while querying the NTP server, but all you really need to be concerned with is the final line in the output text, and of course, the clock displayed next to the button…
Everything is contained in a single runnable Java ‘jar’ file, so just save it wherever you like, and double-click to run it…
Download from here, and I hope your SOLing is more accurate! 😉
Edit: You may ask “What is the point if I have to manually adjust my clock?!” – good question – well initially I had intended this app to also automatically adjust your clock as well, and once I got to that stage of the code realised it wasn’t so simple to support this on multiple platforms (which is why I wrote it in Java in the first place!). So I decided to just output the correct time in the clock label and post it anyway… (and give me some time to look into auto sync) Also, you can run it as often as you like. Computers gain/lose time at different rates, even sometimes gain and other times lose – I have sometimes noticed my own clock was (for example) behind by 20 seconds when I first synced the time, then 2 hours later it was 20 seconds behind again, and in a further 2 hours was 32 seconds ahead! Go figure….
If you are doing a serious racing session, particularly the shorter races where every 500ms you can gain on opponents counts, then you will want to sync your clock every few hours. Considering some 300+nm races have come down to only a few seconds, for the win, at the finish line… Not to mention how close non-podium places can be (SOL times you to the millisecond!), and you can easily see it all adds up. That 30 seconds may mean 5 places! 🙂