On risk attitude and optimal yacht racing tactics

• We propose a novel method to optimise the racing strategy for a sailing race.
• We compute policies minimising the expected time to complete the race.
• We introduce for the first time a model of the risk attitude of the sailor.
• The optimal risk attitude depends on the position with respect to the opponent.
• Being an average slower might allow a higher probability of wining.

When the future wind direction is uncertain, the tactical decisions of a yacht skipper involve a stochastic routing problem. The objective of this problem is to maximise the probability of reaching the next mark ahead of all the other competitors. This paper describes some numerical experiments that explore the effect of the skipper׳s risk attitude on their policy when match racing another boat. The tidal current at any location is assumed to be negligible, while the wind direction is modelled by a Markov chain. Boat performance in different wind conditions is defined by the output of a velocity prediction program, and we assume a known speed loss for tacking and gybing. We compare strategies that minimise the average time to sail the leg with those that seek to maximise the probability of winning, and show that by adopting different attitudes to risk when leading or trailing the competitor, a skipper can improve their chances of winning.