There are a range of controls on most boats that allow you to control sail shape which controls the power generated. Particularly in a boat like a 5O5, which has a lot of controls which we need to adjust regularly as conditions change, it is very important to know where in its range each control is set. This means putting marks on the boat and control lines.

The pictures show typical calibration marks. The video describes how International Yachtsman, America’s cup tactician and multiple Australian 5O5 Champion, Robin Deussen uses colour as an easy to reproduce calibration system.

This boat has used the non-slip to easily see how far outboard the jib lead is set.

The various Tuning Grids are useful but assume you have calibrated all the various controls the same way. Using consistent calibration is very useful, if not essential, when tuning with other boats and replicating settings from one boat to another and from one day to another.

The head of the centre board is marked with numbers which correspond to a wind speed.

On the bulkhead this boat has a table to remind the crew where the centreboard is set for the different wind conditions.

Ultimately, however the centreboard should be set to give the boat best balance. Experiment and learn how the boat feels when a centre board is raked too far.