Calibration

 

Rob reports on Sundays activities……

Sunday’s big job was the calibration of the entire instrument system. A high reward job prior to this weeks final SSANZ B and G  Simrad race, a 100NM race that will surely take us well into the early morning hours (quality instrument time).

 

Nexus NXR multi display.

First up I spent some time customizing our Nexus NXR Multi displays  shown above.. A fun job deciding what information I would like displayed. As we now have just about every possible instrument function we could want it’s a matter of information management, what we want, where. The computer interface via the NXR software made this easy.

 

Second was the calibration of the system. It’s just vital to have confidence in the accuracy of the system in order to make the very best tactical decisions. The most important variables are boatspeed, wind angle and speed and compass course. Other functions are derived (calculated) from these so it’s really important they are as accurate as possible.

 

Third is setting the damping and update rate of the displays, settings that have a surprising effect on the readability of the instrument.

 

The compass was most interesting as we have a total of 5 compasses on board, and it’s really important they all agree, particularly the 2 ‘Plastimo’ bulkhead compasses and the solid state Nexus HPC compass (the others are the hand bearing compass and the autopilot fluxgate compass).

 

Nexus NXR HPC compass

The HPC is a very accurate tool that will also give us heel and trim (longitudinal) angle data, its roughly the size of a pack of cards but lighter, at 40grams. The trick is to isolate the transducer as far as possible from other magnetically disturbing objects, run the autodeviation routine and check its accuracy on headings right around the compass.

 

The big surprise for me was finding that the Plastimo bulkhead compasses that I had set up 3 years ago had developed inaccuracies, probably due to changes we have made around the boat. Fortunately these compasses have an easy to use corrector magnet system and we soon had them back on track.

 

With Expedition and Nexus working together we have everything we need for performance monitoring and that’s a huge improvement on where we were. We can’t wait to start refining our polars. We have set our Expedition performance software to log everything to a database at 1hz (that’s everything, every second), so we will be generating quite a record of performance.