Heaving to is easy. I've done it many times inadvertently. You're sailing along nicely, not paying attention to the wind and all of a sudden your jib decides to switch sides on you. You haven't released the jib sheet so the sail only swings halfway over. The mainsail follows suit and you're dead in the water.
Now you're stalled, sideways to the wind and going nowhere. It can be embarrassing in the wrong circumstances. But, take heart. You can always smile and tell your guests that you decided to heave to and take a break.
When you're finished 'heaving to' you are considered 'hove to'.
As you can see, heaving to is not a complicated maneuver. Doing it properly takes a couple more steps. Ease the mainsail, turn the boat into the wind and lock down the wheel or tiller.
The physics is simple. The backwinded jib is pushing the bow to leeward (downwind) while the mainsail and the wheel or rudder is pushing the stern to leeward as well. The result is a stalemate. The boat drifts sideways at about a 40-60 degree angle to the wind. The boat will move forward at about 1-2 knots and drift slowly sideways.
An important consequence of heaving to is that as the boat slides sideways, it creates a slick on the windward side that knocks down oncoming waves
In light winds, heaving to gives you a stable platform to perform simple tasks like taking in or shaking out a reef, prepare and eat a meal or just relax for a while. It can be employed so quickly that it's even useful in man over board situations.
In storms at sea, heaving to under reduced sail can be a life saver. It allows you to go below, batten the hatches and ride out the storm as long as you're confident that your drift heading will not take you into shore or shallow water.
Heaving to is a valuable tool that should be in every sailor's repertoire. I usually practice it every time I go out.
