Test sail 3rd Jan 2023

Another cold, dark, windy, and very wet evening at the lake.  Following the learnings from Sunday's sail, where the wind vane was causing us problems, we reconfigured EasySailor to use the Wing's compass and tail setting to infer the wind direction.  The hope was this would give us a more robust wind heading than the small wind vane on the hull.  

We also added an RC receiver into the hull so we could take manual control if needed, hoping to avoid another rescue mission in the dinghy.  

Things started off pretty well, we're getting much faster at setting up and checking compass calibrations before dropping the hull in the water.  As the wind was a strong South Westerly, we launched into the wind with a simple back-and-forth waypoint mission just offshore.  This was in case of issues, at least the boat would be blown back toward us!

EasySailor steamed off toward the first waypoint and then immediately turned NE toward the second, reaching it soon after.  The Wing as a massive wind vane seemed to be working well, everything behaving as expected.

As it turned to head back to the first waypoint, EasySailor was clearly struggling to make headway and instead stuck amongst a lot of short tacks, interspersed with gybes.  There appear to be a few issues going on, but the most significant is the gusty wind was causing the wing to swing around a lot - this in turn caused the course planning module (the Sailor) to keep replanning the tack.  We really need a long-term average of the wind direction to plan against - more as a human sailor would do it, ignoring any short-term variability.

That situation continued to get worse until we decided to invoke the manual override and switched to RC control, manually sailing her back with some fairly long, stable tacks.  Manual performance was actually surprisingly good and could make headway up to maybe 40 degrees off the wind.  We did try a burst of downwind, but as expected, it wasn't great.  

Although the regular wind vane had given us major issues last Sunday, today the overall histogram seemed pretty consistent with the wind patterns we'd observed.  Strong, gusty, but mostly from the South West.  

However, another issue observed in the log data was the fancy new tilt-compensated compass (CMSP12) seemed to lose its calibration over the course of the sail.  By the time we had manually sailed back to the slip, it had drifted out by almost 160 degrees!  

Overall conclusions:

• RC manual control is fantastic - we need to add that to all the boats
• Both Wing and Wind vane swung all over the place - need a long-term average to plan against.
• Tilt-compensated compass (CMPS12) doesn't seem as reliable as the simpler compasses we were using before (HMC5883L or QMC5883L) - needs further investigation.  We may be able to store the calibration to EEPROM and avoid it drifting. 
• The Angle of Attack (AOA) for the Wing is probably more aggressive than it needs to be, we should tweak the servo map to reduce this.
• The tacking algorithm needs a revisit, with two aspects to adjust: 1) reduce the number of small tacks it currently makes - ideally we want to hold a tack for longer to make more progress.  2) tack more like a human, bearing off the wind to build a little speed before a sharp turn across the wind.
• The Polar map for EasySailor is a little more cynical than it should be.