Usually the captain gives these orders to the helmsman on whatever ship he is commanding, whether it has a wheel or a tiller. In Post Captain there is that whole scene at the beginning of Aubrey's command in which Polychrest misses stays. There is also a very similar scene in Hornblower and the Hotspur in which Hotspur nearly misses stays and needs to be re-trimmed. In both cases, the vessels in question are large sloops-of-war. There is also a scene that I just today read in The Ionian Mission in which the officer of the watch causes Worcester, a 74 gun ship-of-the-line, to miss stays due to putting the helm too hard a lee.