For most sailors the goal is to sail as fast as possible whether racing or just having fun. But you need to know how to slow the boat down sometimes, such as when approaching a dock or mooring or an obstruction.
Slowing a sailboat is fairly simple - you just do the opposite of what you do to sail fast with well-trimmed sails! (Well, it's almost that simple.)
The best way to slow down is to "spill wind" from your sails by letting out the sheets until the sails are luffing - or even further if needed until they start flapping. This means they're not working efficiently to drive the boat forward, and the boat will quickly slow down. You need only to tighten up the sheets again to regain speed if you want - or continue to let the sheets out until the sails flap uselessly and the boat coasts to a stop.
There is one exception to the "let out to slow" rule - when you're sailing down wind. When you are running, the sail billows forward, and it may not be possible to let the mainsail out far enough to spill wind because the boom hits the shrouds and won't go any father. The sail is still full and the boat moving right along. In this case, pull the mainsheet way in to slow the boat - less sail is thus exposed to the wind, and the boat slows down. But do not try to slow down on other points of sail by tightening the mainsheet! On a beam reach, for example, tightening the sheets may slow you but can also drastically increase the boat's heeling, and you could capsize! Instead, let out the sheets.
The next page looks at how to stop the boat altogether.
