Learn how to sail faster, make the right calls and win races. On-board instruments present modern sailors with a wealth of information. This book explains what the numbers really mean, and turns this information into racing results. By mastering your instruments you can make the right calls everytime and know for certain when to tack, which shift to look out for and how the tide can work with or against you. With colour diagrams throughout, this instructional guide turns information into excellence. Accessible to those new to racing, it also has a depth of information that will transform the performance of even professional sailors. Cruising sailors will also benefit from understanding how to get the most from their instruments.