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Gybe question


Advanced Beginner
Blogs Author
Perhaps a picture would help.

Maybe a word picture?

Imagine running downwind in breeze, starboard gibe. Main is all the way out against the port shrouds.

To start this thing, turn to port... how aggressively you turn depends on a number of things, not the least of which is the size/spacing of the waves. You generally want to do this between waves, not be in the middle of the gibe at the top of a wave. It should be a real "turn", though, maybe 20-30 degrees of heading.

At some point, as you turn to port, the leech of the main will start to collapse as the sail begins to feel breeze on its leeward side. At that point there's MUCH less load on the main than there was previously.

Grab the mainsheet and snap it to start the main swinging through. When it gets to the other side, it will be luffing (because you're headed "up" a 20-30 degrees on the new gibe). It won't make a big crashing sound. Honest.

Then fall off to starboard to get back on course. You're now on port gibe, running with the main against the starboard shrouds.

It's called the "slalom" technique because, if you look back, you'll see a big "S-turn" carved in the face of the wave coming up behind you.

I spent a bunch of time on fully-crewed "sleds" (70-foot ultra-lights) that used this technique in open ocean.... and can assert that this works great, even in big waves, even with a 25-foot boom on the bottom of a 750-square-foot main. It depends on a good driver and - if the rig has them - good people on the running backs. But ends up being far less stress on the rig than grinding it in on one side and letting it slam against the rig - or pin the boat down - on the other.

Edited to add: crude attempt at a picture


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Sustaining Member
Kinder and gentler

I think I'll stick with the kinder and gentler technique. As you are bringing the main to the centerline you also turn the boat to get it into position for the new tack. Turning as you ease out the main. Regardless, always take account of the strength and direction of the wind. In shifty winds all techniques are tricky.

G Kiba

Member III
I'm guessing that all the advice seems real good and works for each of them on their boats. So I'll add what works for me...

No preventor or other additional hardware needed!

1) Sheet in the main (or have crew do it) but don't lock it down.
2) As you sheet in, slowly steer through the jib. Watch for the main to shift to the new windward side then let out the sheet.

Takes a bit of practice so try it several times on a lighter wind day till it becomes simple.

I have done this on the SF Bay in 20-25. Works fine. Can't see why it would be different on a larger boat. But what do I know?

G Kiba

Member III
I take that back about larger boats. I did this a few years ago on a 50' Hunter in about 15 knots winds.


Member II
Gybe question answered

Wow. Thanks for all ideas. Sounds like one of those things where in the end you go find what works best for you.


Member III
Boom break

If you're cruising short-handed or solo, and you are doing long downwind stretches and don't want to be a the helm all the time (e.g., under autohelm or windvane), then you would consider rigging either a Preventer (lot's of on-line resources, opinions and methods) or a Boom-Brake.
The latter allow the boat to do an uncontrolled gybe without the 'crash' while no one is on deck. There are also a lot of choices here too - and a fairly good You Tube video comparing the main types (but the wind was very light in that comparison). Boom Brakes range from very expensive (hundreds of $) to simple ones based essentially on a figure-8 belay device. I bought this one: https://dreamgreen.org/boom-brake
I've rigged it and played with it, but haven't used it in anger yet. ;-)

I use a boom brake on my E32-3 especially when I single hand the boat and it works great if rigged properly. When it's really blowing it's very difficult, if not impossible to "center up" the boom, so IMO you're going to need something to take the jolt out of it. I haven't tried Christian's suggestion yet but will this season. But ever since I've been using the boom brake there had been a marked reduction in anxiety in jibing and a lot less stress on the standing rigging and boom. I won't explain the rigging of a Captan Don's boom brake here but its quite simple and with a little practice very easy to use especially single handed and with the control line running after to the helm area. It also won't "break" the bank.
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Member II
I use a boom brake on my E32-3 especially when I single hand the boat and it works great if rigged properly. When it's really blowing it's very difficult, if not impossible to "center up" the boom, so IMO you're going to need something to take the jolt out of it. I haven't tried Christian's suggestion yet but will this season. But ever since I've been using the boom brake there had been a marked reduction in anxiety in jibing and a lot less stress on the standing rigging and boom. I won't explain the rigging of a Captan Don's boom brake here but its quite simple and with a little practice very easy to use especially single handed and with the control line running after to the helm area. It also won't "break" the bank.
Thx Bob. —-looking them up now

Leslie Newman

Member III
I'm still old school and when going to be in a blow I rig some boom preventer lines to blocks tied to the bow cleats. Run the lines from mid boom works best, outside the shrouds, up to the blocks, then back along the cabin top and they slip through slots in the dodger to my cabin top winches. If I am wing on wing I use the preventer and also when I Gybe. I tried them this past weekend tied more towards the boom end and that didn't go so well as one line I let get slack got caught on the dodger once. So I moved them back to mid boom soon into our sail.


Member II
Wow, it works!

Anything that feels right works, and I don't wish to detract from others' technique.

I jibe full mainsail in 20 knots without touching the main sheet, and certainly without trimming in. I jibe in 30+ knots--have done it a dozen times--the same way (In heavy air, you're deep reefed. The mainsail forces are actually trivial, its dodging breaking seas that's important).

It is technique, and the technique is easy to use. It is mandatory for singlehanders, but available to all.

Pick a spot among the waves. Steer the yacht by the lee. Initiate the jibe with a radical turn of the wheel. Continue the radical turn until the wind is abeam.

What happens is: the turn beats the swing of the mainsail. BY the time the sail completes its violent transit across the deck, it luffs, rather than "bangs". If that seems unlikely, consider the momentary hesitation as a mainsail finally folds its roach and decides to come crashing over. During that period the yacht is spin-turning and gaining the advantage.

It is then necessary to resume downwind course by a hard spin of the wheel the other way, and alert timing is necessary to avoid momentum carrying the yacht head to wind in breaking seas.

There's a downside to trimming a main sheet before a jibe, and that is that the sail trim is momentarily all wrong, and any broach becomes dramatic--and the sail must be paid out very quickly after the sail crosses over--which is a handful, and a foul always threatens.

In the days of long booms, booms could rise up and take out the backstay. Our booms can't and won't. Boats with running backstays complicate things. Our boats don't usually have them. We have fin keels and spade rudders that turn us on a dime, making this technique possible. A full-keeler can't do it.

Try the technique in ten knots, see if it works. You should feel and hear no "bang" at all.

[Not a technique for use when overlapped by four boats at a race turning mark, or when jibing under spinnaker.]

After reading about this technique I was excited to try it and finally worked up the guts yesterday in 15 knts. This may be life changing for me as I single hand constantly and hate jumping around the cockpit messing with the main sheet during a jibe, I've also rounded up violently when a guest didn't release the main sheet as fast as I would have liked, I don't tend to sail ddw so I never rig a preventer which is also a liability when single handed i think. It worked so well I did it again and again - no bang. Thanks for sharing Christian.
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Member III
Like others, I'm intrigued by Christian's advice, and will try his technique at the earliest opportunity. His video is very helpful.

After talking to Loren a couple of years ago, I replaced all of the stock mainsheet blocks with ball bearing Garhauers. This was a good move, but the there is still a lot of friction, which leads to near-broaching on gybes when the sheet does not go out fast enough.

I want to mention the other gybe issue: controlling the genoa. I find that the headsail can cause problems too, especially with inexperienced crew, The temptation is to release the sheet completely which allows the sail to go forward of the forestay and, more often than not, to wrap itself around that useful item of rigging. Pulling it back can be very difficult, sometimes requiring an unwanted return to the original tack. To avoid this situation, control must be maintained on both sheets throughout the gybe, keeping the tack of the jib inside the fore-triangle.
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Sustaining Member
O.K. fellas and gals...just had the crapola scared out of me....on lake today, nice 10 knot breeze on a broad reach, passed a cliff type island that I had passed many many times before above the Colorado river bed 165' deep which is typical... and witnessed to my displeasure an accidental jibe the likes of I don't want to rehearse! I don't have a preventer or boom brake..who needs one on a beautiful light breezy lake? Between the boom vang and main sheet...used for typical light jibe control for decades.

The very light wave action after passing the island quickly changed direction for reasons unknown, and an unexpected breeze whipped around the island causing the accidental jibe. Yes I may have been enjoying the sail too much for my own good. Kinda mesmerizing. Going to get a boom brake asap, as per Bolo's post above! My boat has a 13+' boom and its whipped velocity under a lazy main to opposite full in less than a few seconds was impressive! No damage, no one hurt thank goodness, only my pride as captain.


Contributing Partner
I had the same kind of thing happen on my old San Juan when I passed behind a fully loaded Container Ship on San Francisco Bay while it was blowing 25kn. That's a normal summer day on the central bay. The wind suddenly stopped and reversed hard. There we were laid over with the jib reversed being sucked in toward the container ship. Scared the cr** out of me. You learn to see these situations coming after experiencing them.
The wind shift would have shown on the water. After a bit, you learn to automatically see them. I do use a preventer (3 part block and tackle snapped to the boom and rail) when I am on long runs deep off the wind so I can properly glaze out. I've never felt the need for a boom brake.

Keith Parcells

Sustaining Member
Islands and ships as big as an island, can create odd and unpredictable wind and wave phenomena. Waves can wrap around the point of the island and hit you from another direction. The wind can do the same, OR it can be funneled, especially by canyons on the island or between two islands and it can result in a vortex effect and greatly increases in strength and speed. It can be tough to predict! It can knock you on your ear! Voice of experience here.

Another scary phenomenon is when a strong ebb tide s running out of the harbor and meeting a stiff breeze blowing in. Oh my gosh can that build very large waves and coming into the harbor is like being a surfer, in reverse.


Sustaining Member
In moderate conditions I prefer to control the main during crossover. Bring the main in to a quartering position. That is about where it would be on a close reach. Then make the turn and let the main flop over to quartering position on the other tack. Then ease it out. Puts low stress on the rig and skipper/crew.

In heavy air this may not work because it may create too much weather helm to actually jibe. Possibly means you are flying too much main for the conditions. If I were caught in this situation I'd tack around instead of risking a flying jibe.

To help avoid unexpected jibes try to develop a reflex of turning towards the wind whenever you get even a hint that a jibe could happen. One such hint (in moderate conditions) is that the helm gets mushy; feels like the rudder is not connected. If you practice enough you can just feel it and automatically point up to avoid jibing.


Sustaining Member
Fellas you are all absolutely correct. In retrospect to my post 33 above...all my undoing. If in command of a ship, be it plane, boat or car...don't ever act as a relaxed passenger. Little nuances can bring huge surprises. It has been said again and again; instructor after instructor, book after book: Situation awareness is solely in the pilots/captains hands. Always enjoy the environment or you would not be there in the first place, but don't ever let awareness down. Lesson learned and so aptly stated in post 34 above: "I doubt this will ever happen to you again because experience is its own boom brake."


Member III
Thank you Christian and Bruce. Something new to practice! I've never really liked pulling in the main on a gybe because I have to let it out so fast and if a tangle happens....

Mark F

Contributing Partner
Blogs Author
What a great thread. How did I miss this? I use Christian's suggested technique in light winds all the time but never thought to do it in heavy winds. For me single handing in strong winds I sheet in the main, gybe (the main), let the main out fast then settle into a wing on wing sail set. At that point it is easy to gybe the headsail. Sometimes I will gybe the headsail first, go wing on wing than deal with the main.

I am interested to try gybing the headsail into wing on wing (over sheeting) then use the "slalom" method to gybe the main.

Hmm, I wonder if it will get windy today...