Jibing the mainsail

[Don Guillette]

I like to see a smoothly executed jibe. It only requires a little practice and a basic understanding of what is happening and the jibe becomes no big deal. Without practice and understanding, an uncontrolled jibe can be a bloody mess and it cancreate havoc and damage. The boom swings wildly over, the boat boat broaches sideways and the boom slams over to the other side thus raising hell with you hardware. Additionally, if the boom hits someone on the way over, your whole day can be ruined and this could end up being a very costly liability situation. Like everything in life (and sailing) there is an easy way to do things. The following is the proceedure I follow. The boat driver must control and set the pace of the maneuver and he has to effectively communicate with the crew as to what is about to happen. The first thing he does is tell the crew that they are shortly going to jibe the boat at some point in time. Next, the boat driver should discuss the stages of what is going to happen. Some might think that is over kill but unless you have an America Cup crew those few minutes each time will avoid problems.Next, the boat drivers makes sure everyone is in position and that the preventer is detached. Strange as it may seem, sometimes detaching the preventer is overlooked. Everyone should be advised that the preventer is detached because this is now a dangerous time.Next, the boat driver should come up a few degress to stabilize the boom and prevent an accidental jibe. When he is sure things are stable, he then steers to about 150 to 165 degrees true wind. At this point the mainsheet/traveler trimmer brings the traveler car to the center of the track and takes up as much slack as possable in the mainsheet. Most importantly, he must be sure that each end of the traveler line is locked in placed. The implication of not doing that step is obvious as the car will go slaming over with the boom.Next, the boat drives asks if everyone is ready to jibe. He must get an affirmative from EVERYONE. He then states "prepare to jibe". Heads should be down as soon the boom is going to snap across. He then calls "jibing" and starts turning the boat. The mainsail trimmer now takes up mainsheet slack as quickly as possable. On some boats he can physically grab the mainsheet below the boom and control the boom. If it is a inexperienced crew the most important thing is for the boat driver to go slow. Once the boom goes across and the pressure is taken up by the traveler car, the mainsail trimmer can start to reposition the traveler car and trim the mainsail, if necessary. Don't forget to attach the preventer.The other thing to remember is, that while all this is going on, the jib is coming over to the other side but with a controlled mainsail jibe the whole manoever becomes a well controlled choreography of motion.

 

[OldCat]

Why not . . .

Why not: Head up before releasing the preventer? Then the risk of accidental jibe is low.With kids on board, I am always reluctant to sail deep down wind in any event - I'd rather go down on a series of deep broad reaches & eliminate as much as possible risk of accidental jibe. Sailing that way, the jib will collapse before the main jibes - it is a warning to head up. This feels safer to me even if it means that I don't practice wing on wing very often.

 

[Don Guillette]

Why not

Oldcat: Like I said.... the proceedure I outlined is the one I use and which works for me. I came upon it by trying a couple of differents ways, including the one you suggest. The way you release your preventer is up to you. Some mates, on the other hand, just untie it regardless of their point of sail. I don't agree with that but if they are satisfied who am I to argue.As always on this forum, I recommend that every lister take every suggestion presented and try it on their boat. It is like buyer beware and your only investing a few minutes of your time to check it out. That is what I've done with so many systems so many times I can't count them. After you check out the options suggested, then it is easy. You just pick the one that works for you. What works for you is EVERYTHING. As a point of infomation, I will never offer a suggestion on anything that I have not checked out first on my boat and confirmed that it worked for me. That and 25 cents - oops, I'm dating myself - $1.25 and you can buy a coffee!!

 

[Augie Byllott]

jibing

I singlehand an Irwin 38CC that has no traveller. The six part mainsheet runs to a block mounted centerline on the coaming behind the helm.Three seasons ago, on the first tack on my first sail, the uncontrolled boom flew across and to say it frightened the hell out of me would be a gross understatement. I vowed to never let that happen again.I secured the center of a 40' length of 7/16 braided nylon line to the bail which carries the upper block for the mainsheet. I mounted a block on the port genoa track on the toe rail, one on the starboard side and an 8" cleat port and starboard on the cockpit coaming aft of the sheet winches. The end of the lines were fed from the boom bail through the blocks on the toe rail and laid alongside the cleats waiting to be used as preventers. Under sail, when the mainsail has been trimmed, all of the slack in the preventers is taken up and the lines cleated. No chance now for a jibe, accidental or otherwise, because the boom is held in place and cannot move.Prior to a tack or jibe, I center the boom by adjusting the preventer lines. Then I make the maneuver, relying on the jib to bring me around. After the jib is trimmed I trim the mainsail. Then I adjust and cleat the preventers. Once again, the boom cannot move. Tacking and jibing are slow, sloppy, and far from pretty. However, the system enables me to sail.

 

[OldCat]

I once sailed a similar boat. . .

(Augie) I once sailed a similar boat. . . No traveller, no boom vang, mainsheet blocks and winch on the rear cabin (center cockpit) - it was not my boat, I was just crew.Here is how we jibed: sheet in hard as though close hauled, jibe slowly, then ease out the sheet a bit. Pretty undramatic - & pretty much as Don described - except for the lack of the traveller - and the way I was taught in ASA sailing school. I don't really understand why you need the preventers to jibe - sheeting in with the mainsheet before the jibe and out after should remove the drama from it.BTW: not having vang or traveller really stank. The trim was almost never decent. Neither the genoa nor the main could be brought in far enough on that boat, so tacking was an unweatherly affair. Downwind was little better - can't really sheet out unless there is a vang to control shape. The boat only trimmed reasonably on a reach.Hopefully you have a vang? At least then you can sheet out w/o the sail becomming a bag.

 

[OldCat]

Don:

Mostly, my question was just that - a question, not a criticism.Actually - none of my boats has a preventer & so I don't use one.On my catamaran about the deepest that that boat can be sailed downwind is 90 deg apparent. Small cats are jibed downwind as the rig is too inefficient if the flow detaches.On the J, I don't sail deeper than a broad reach - to kill the risk of an accidental jibe as I almost always have kids on board. Thus neither of my boats has much risk of accidental jibe.So - I was just asking about preventers due to a lack of experience with them.Otherwise - I don't see how anyone jibes any way other than your (Don's) method w/o killing something. The only refinement that I may add on a small boat is to have an uncleated mainsheet in hand so that the sail can be eased out *quickly* after the jibe to control heel. On the J, I'll have the vang set to control twist, and adjust traveller and mainsheet more carefully to each other after the jibe is finished and everything is calm and easy.I'm no expert - so (anyone) feel free to correct me if I've got something wrong.

 

[Don Guillette]

Oldcat: I re read my comments and I can see where your coming from. I sometimes answers questions and then I ramble on preaching to the general forum audience and I generally throw in a lot of other stuff, like testing ideas etc. So the majority of the mesaage was directed to the general forum.On preventers - I guess it depends on the size of the boat. Maybe starting with 27' but definately anything over 30' should use a preventer. I have seen folks rig all kinds of preventers. I've seen guys attach them to the little rings on stanchions where the safety lines attach - that would last about 1 milisecond. Mates should find a secure attachment spot. Also NEVER, EVER use a bunge cord. Those suckers are dangerous. I was talking to a paramedic friend of mine from Long Beach and he told me about a marina run they had where the end of the bunge cord actually stuck in a gals eye!!I was thinking about the first part of my proceedure where I come up a bit to stabilize the boat and I got to wondering why do I do that? I don't know why I do it other than an old Greek sailor taught me to do it that way and I'm too old to change.

 

[Bob]

Amen, Don

A good buddy of mine is a nurse, and he told me that the leading cause of eye injuries is now bungee cord accidents. They are OK for strapping things down, but NEVER use them as any kind of sail controls or preventers, and when you stretch them, treat 'em like you would a loaded gun - stay out of the line of fire.

 

[Kaizen]

Boom Tamer

I found this boom tamer device, see link. I might attempt to make one myself this winter. The theory seems sound and simple. It just slow down the boom coming over.

 

[Alan]

A very easy preventer.

Attach a line on either side of the boom at the aft end so that it nearly reaches the gooseneck. Splice a ring into the other end and Attach it to the boom with a bungee. Run another line with a shackle, from the mast, forward to the bow and back along the cabin top to a cam cleet. When it is time to rig your preventer, attach the shackle to the ring and snug the line. Now the main CANNOT accidentally jibe. To release the preventer, release the line at the cam and open the shackle, jibe the main and attach the shackle to the ring on the other side of the mast.

 

[RichH]

Old cat - in your gybing method with an.....

.... uncleated mainsheet and especially for 'lightweight' boats that tend to be easily broached.....keep the mainsheet uncleated and be prepared to steer quickly *into* the direction that the mainsail moves to ... so that you can re-balance the boat and keep the mast: "dead straight up and over the boat". The tendancy for 'lighweighters' when gybing is to allow the boat to 'round up to weather' hence risking a broach. If you purposely steer more 'down' the boat WILL accelerate like a banshee but wont have the tendancy to 'round-up' and broach. Scows and other planing boats do this as a 'routine' ... works on heavy keelboats too.

 

[Mike]

Don, a question for you

Don, Answer me this. I think that I am gibing safely with my C22. However, the way every one here explains it, it sounds like I'm doing something wrong. Here's what I do. When gibing, I maintain my compass heading, and slowly bring the mainsail to center. I then SLOWLY change my course to the new heading, adjusting the genoa to the new heading. I then ease the mainsheet slowly to where it seems most efficient. I also have a stopper knot in the mainsheet to keep the boom about 6 - 8 inches away from the aft shrouds. I do not want the boom to be able to slam into a shroud in case anything gets away from me. Am I over - simplifying the gibing procedure?

 

[OldCat]

Question for RichH

RichH: Are you saying to sail back down - back to further off the wind to control heel? That sounds OK for the J if I need to control excess heel - sheet in and head down - but I was mostly talking about getting sheeted out for the broad reach I was aiming for, as on a broad reach it will heel too much if sheeted in & the sail will stall and lose drive.So far no broach for me - so maybe I am missing something in the reading and writing - lucky or doing it right on the water - I am not sure. I took the ASA courses when I decided to move up in size and am pretty sure that I am jibing per what I was taught.I think there may be some differences between the J22 and the NACRA - both of which I sail. The NACRA is *REAL* slow downwind unless you are reaching down wind at 90 deg apparent. I have not sailed the NACRA much the last few years - so I am relearning its tricks. I don't think it will get anywhere near a broach in the winds I will be out in for a while - if it will broach at all, it would likely capsize or pitchpole first. All I have ever been able to do was capsize it - but I have seen others pitchpole catamarans - not fun. I have never seen a beach cat broach - but am not completly sure it can't be done. It would be hard to do on the NACRA given the hull shape - there is a lot of bouyancy in the bows of my boat to resist turning as they dig in under the sail forces. I need to go read a book on catamaran sailing - now that I have that boat back together - too many years off the cat & I can sail by feel but there are fine points I have forgotten.This forum is an education - but I am not sure I understand why not to sheet out for my intended point of sail after the main pops from the jibe.

 

[RichH]

Old Cat --- yup!

Especially in a lightweight planing hull boat during a gybe what usually 'gets' you is the momentum of the maneuver: the momentum caused by the swinging boom, and the pendulum-like movement of the mast .... all creating a lot of momentum that tries to make the boat heel over and turn up into the wind quite a bit 'more' than you intend. To counteract such momentum, turning the boat MORE downwind immediately as the wind takes the 'other side of the mainsail will tend to stop or counteract the tendancy to over-rotate the turn and extra heeling of the boat. As soon as the boat (momentum of the gybe) is under control, then you can head off on any track you want to. It really makes for a 'quieter' gybe especially when the winds are 'up'. Its a 'trick' I learned sailing scows and other planing hulls where when threatening to capsize, etc. you drastically bear-off rather than 'head up'. Bearing off, puts the mast squarely over the boat (balance), counteracts the momentum, etc.and gives better 'dynamic stability' because the boat is now much 'faster'; .... what I'm doing is 'power-sailing' out of a possible capsize/broach ( ... and hope to hell that the bow doesnt go under and the boat become a 'submarine'). I find that a heavy keel boat benefits (stability) from the same maneuver .... just an extra 'kick' downwind with the rudder immediatelly when the sail changes sides until all that motion (turning,heeling like a pendulum, etc.) quiets down and then I can sheet-out, etc. and steer to the new intended course. Another way to look at it: My gybe-turn looks almost like two "S' turns -- connected top to bottom of one another ... a 'squiggle'; in contrast most others use a simple "C" turn. I hope this 'details' it for ya. ;-)best regardsRichH