So OK ... continuing report on VMG to waypoint via Garmin 440s
today initial test of following Garmin's secret method of getting VMG to waypoint on 440. It is not in the manual. we input the above referenced procedure and with a couple of coin flips we actually got VMG to work, but after about 15 minutes it would crash and the screen Wpt VMG would return to _._ kt display. requiring us to reset the waypoint.
However ... as with any new application it is not just the instrumentation, but what we were trying to interpret that is in a learning cycle.
so bear with us on this quick report
1. the course Photo ... start at tower leading into Gordon Pass [GP Safe] ... then tight haul on port about 3 miles then tack to point ~ dead upwind of GP to start a spin run back. this is sort of standard race sequence. The photos are not taken at exact points of the test.
[our objective was to see if running hotter by 10 degree hits would change the VMG in a beneficial way. ]
2. magenta line is course to turn
3. Black line is track/heading marked in miles for the std tack
4. Red line is return to GP under spin.
top display picture is the VMG on the cross leg ... it started around 2.3 kts and dropped to ~ -.2 or so when we launched spin. normally this would have been a set windward mark, but we used the lowering of the VMG to simulate the arrival at the mark.
wind was high enough to keep us over 5.5 with gusts taking us to 7.
bottom display picture is running back to GP pretty much on course.
a 20 degree heat up did give us +1 kt but no real increase in
VMG.
Rough lessons learned.
1. Running hot in 10+ kts doesn't seem to help, which is reflects J30 SOP
2. the speed readings on GPS Auto are too fast to easily follow ... will take averaging time to 5 seconds, wind was out of the south with 2-3 waves and some boat motion.
3. matching the speed and VMG is nice to have a good idea of the right course to steer
4. Garmin 440 either lacks decent VMG to waypoint power ... or we are going to have to find more secrets to its operation.