It’s not running a boat onto a coral reef. Some people do that of course, but that’s just called running a boat onto a coral reef.
“Reefing” is bypassing part of a sail so it’s temporarily smaller. It’s done when a boat is overpowered, or about to be, by increasing wind. It can be done with almost any mainsail, which is the one attached behind the mast, and some genoas, which attach to the front wire supporting the mast (headstay or forestay).
Here’s one of our Beneteau First 21 sloops sailing conservatively with a reef in the main, and the small jib (front sail that doesn’t pass the mast). It was windy and gusty that morning as we prepared to be interviewed and filmed by Fox 5 News. There’s a link below to the story and video on their site, which shows this reefed mainsail well…
The details differ, but the concept is the same. Smaller sails equal less power. Less power means the boat doesn’t lean (heel) to the side as much. Too much healing to one side makes the boat try to turn the other way (due to buoyancy and deflection and other mumbo-jumbo), and there’s less control. It’s also somewhat uncomfortable and potentially a little dangerous if people slide downhill, so to speak, when the boat heels too much. Most people find heeling fun, but it can freak out beginners until their body accepts what their mind keeps telling them: sailboats are meant to heel, and it’s not inherently dangerous.
So, back to reefing.
It’s a powerful tool to reduce heeling, and not only gives the boat more control, but maintains its speed. Yes, that’s right. Less power can equal more speed. Why? Sailboats are less efficient moving through the water when heeled too much, and the turning effect causes the rudder (steering fin) to be held to one side just to go straight. That’s basically a brake.
Reef the mainsail, and it’s smaller. Less power. Less heeling.
But wait – there’s more! (or is that less?) The sail is also lower. When it’s reefed, the bottom is bypassed, so the sail isn’t raised as high on the rig. Less height equals less leverage. Even less heeling.
But there’s a third benefit that’s less obvious. Who can figure this one out? If you learned to sail with us, you might remember this one. Post a comment in reply to this if you think you have the answer!
Here’s a link to the Fox 5 News piece, “Closer Than You Think: City Island.” Check out City Island’s nautical heritage; see us at NY Sailing Center – and take a good look or three at that reefed mainsail!..