While sailboats can sail pointed directly downwind, this is not recommended because a shift in wind direction could cause the sail(s) unexpectedly switch sides (known as flying gybe).
Instead, sailors typically progress downwind by following a zig-zag course, similar to how they would progress upwind, except with gentler 'zags':
However instead of tacking at each change in course, the sailor executes a maneuver known as a gybe (also spelled 'jibe'), where the stern (back end) passes through the wind direction.
How to Perform a Gybe
- Initiate a turn away from the wind by pulling the tiller towards you (away from the sail) using the tiller extension/hiking stick.
- Aggressively sheet in an armful's worth of mainsheet.
- While turning, stand up on the 'old side' and step across the boat without letting go of either the mainsheet or tiller extension/hiking stick.
- Once the sail(s) switches sides (aka gybes), sit down on the 'new side' opposite the sail(s) and sheet out by easing out an armful's worth of mainsheet.
- Center the tiller immediately to stop the boat from turning and re-establish a straight course, looking forwards to ensure that you're now traveling in a straight line.
- Slide your sheet-holding hand aft (towards the back) along the mainsheet to reach the tiller extension/hiking stick.
- Once you've grabbed the tiller extension/hiking stick with your 'old' sheet hand, let go of it with your 'old' tiller hand.
- At this point your 'old' sheet hand becomes the 'new' tiller hand, and it will be holding both the sheet and tiller extension/hiking stick.
- Grab the sheet with your 'old' tiller hand.
- Make sure your sail(s) is trimmed correctly and adjust if necessary.
[Please note: this video needs to be replaced with a version showing someone switching their hands. Also for some reason I decided to rotate the camera :( ]