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The Politics of Calibration

The story of one boat having calibration problems was recently relayed to us. The crew was having difficulty obtaining reasonable numbers from their instrument system, so they began to “calibrate” the instruments. I used quotes because what they were doing was not actually calibration, but fiddling and guessing. After a race or practice, they would talk over the numbers they saw while sailing, and then adjust the instrument according to what they thought they should be. They were getting frustrated because the instruments would constantly show inconsistent numbers, and needed adjustment after every race. The instruments became worse than useless – they became unnecessary weight and a source of frustration and distraction.

There have also been cases where we have been told that the instruments must be wrong, since the driver knew he could go faster than that or the boat couldn’t possibly sail like it did in the conditions indicated by the instruments. After much discussion where we made the case that the instruments need to be calibrated correctly, the crew went ahead and adjusted the calibrations to reflect what they thought were the correct calibrations. This of course created false data which in turn led to bad decisions, and many poor finishes. If I recall correctly, it also led to one boat being sold in frustration. The new owner of said boat calibrated the instruments correctly, and was very happy with the results.

The hazards of engaging in this behavior should be obvious. Anyone trained in science can tell you that forcing the data to fit your own perception or assumption leads to incorrect conclusions. Pilots are very familiar with this – there have been many documented crashes where the pilot chose to follow perception rather than hard instrument data and pranged the aircraft (often with fatalities). A well-calibrated instrument system may sometimes give odd figures, but these may be indications of conditions that can give an advantage when recognized, such as wind shear.

The numbers used for calibration should not be created by guessing or by the T-LAR method (that looks about right). We have a well-established routine for calculating the calibration numbers. The Ockam System Manual contains a detailed step-by-step process for manually calibrating the instruments. It even has work sheets that guide the user through the whole process – what I call the “plug and chug” method. The numbers are plugged into the various formulae, and the then the answers are chugged out. However, some people are simply frightened by math, and avoid doing this. I think this is a bit ridiculous, since the math used is no more advanced than what you might use to balance your check book.

Some people insist on using a professional calibrator, but their services are not necessary to produce good calibrations. A dedicated amateur can produce results as good as a professional. The difficulty in using professional calibrators is that they are hard to find and difficult to schedule. They also tend to charge for their services and expenses. In my opinion, only the largest or most specialized boats really benefit from their services. Some calibrators are also professional sailors, so it may be possible to get a “two-fer” when hiring one, and have them sail in an important regatta. Not everyone can afford to do this, though.

The DeWiggler program can also produce excellent calibration data. I’ve written previously about what DeWiggler can do, and some of the information we’ve gleaned from the results. DeWiggler is probably the least intensive method of running the calibrations. The computer program is set up and run, and it guides the user through the entire calibration process. Depending on the version used (Realtime vs. Analyst), results may be available immediately, or in a few weeks. Not every boat has a computer available to run the DeWiggler program, but those that have run the program have been extremely happy with the results.

Even with good calibration, it is possible to fudge the numbers to produce the desired result. One top-level sailor would adjust the polar data weight during practices so he wouldn’t have to push the boat (and himself) every day sailing. He would make it appear as if they were always hitting or exceeding the performance numbers by de-rating the polar data (i.e., the boat did not have to go as fast to reach the theoretical speed). It didn’t really matter in the end, as he and his crew did quite well. However, anyone of lesser talent would have just been cheating themselves by not measuring performance honestly. How can you improve your performance if you don’t know what you’re doing wrong?

An excellent white paper has already been written on the politics of calibration, and is available on our web site. It discusses the types of personalities encountered on boats with problematic calibrations, and has suggestions on improving the situation.

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