Yes, thanks Nick. I know about using the current grib files but on a closed course, well, a forcast is a forcast. I looked into EXP today and can't find the hold current feature. Is set/drift always factored in for layline calculations or do you have to turn it on? Just asking because laylines from mark and boat always seem to intersect at the same angles on both sides and I've had EXP say it's time to tack when I knew we had to go a couple of boatlengths to make it due to set.
Again, I just try to keep the boat out of the corners and let the crew use their heads for the final approach to the mark.
Do Expedition's "standard" laylines take into account tidal set etc?
They don't, but they do help keep you out of the corners. The laylines from the mark and projected opposite tack lines from the boat are based on TWA. Trying to hit a layline from far out isn't a vary smart thing to do. If you want to go to a corner from far out look at your COG track and when the mark bears COG from the last time you were on that tack, cross your fingers and flip. Best to approach the mark from well within the corners I think.
I was working with the Garmin 19x HVS last week and that device rips. When I test a GPS I put it in one spot and map it on a plotter to see how it drifts from a known position. The thing was rock solid.
There is a configuration tool for the 19x that is really simple to use. You can adjust baud rate and update rate very easily, and then use your instrument system for dampening so your numbers aren't all blinky. You can also filter out the sentances you don't need to reduce the clutter.
Expedition plays nicely with the 19x at 10hZ
The Nexus Race box will take data from the 19x via NMEA 0183 at 38,400 set to 5hZ update for its time and distance to line calculations and it is very accurate. The data from the Race Box will not be passed to the Nexus Server via the RS-232 connection. To get the GPS info to the Nexus server you will either need a second GPS connected to the NMEA GPS Server port or a properly configured multiplexer sending data at the proper rates to both the server an Race Box.
I think jarcher is working with the good folks at Nexus on a better solution, but what we have now works.