we just finished the northu cruising i got for my wife and it contains an item that i had never heard before, but which i consider worth the price of the cd many times over. to wit, THE JIB WILL ALWAYS JIBE BEFORE THE MAIN AND GIVE WARNING OF AN ACCIDENTAL JIBE. if sharing this with other sailors shows my ignorance, so be it, but since i had never heard this before i hope it helps others.
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Mort,
I don't get it. If you're wing and wing, and the main gets backed, how can the jib warn you? What am I missing?
I don't get it. If you're wing and wing, and the main gets backed, how can the jib warn you? What am I missing?
It's the opposite
of what we learned in our sailing classes. When going into the wind the jib will start to go over first. When downwind the main will start to change over first. Best way to prevent an accidental jibe is to sail on a deep broad reach rather than dead downwind.
of what we learned in our sailing classes. When going into the wind the jib will start to go over first. When downwind the main will start to change over first. Best way to prevent an accidental jibe is to sail on a deep broad reach rather than dead downwind.
obviously with each sail opposed, the wind can only get behind one. i am not among those who ever sail wing and wing, nor dead downwind; i hate how the helm feels.
so
as in Freds example, since you have already jibed with the jib then an accidental jibe with the main is always a close possiability? or is that what what you mean? and please don't ask me to clearify it because when i reread the question my first thoughts are stern is right and port is up.
as in Freds example, since you have already jibed with the jib then an accidental jibe with the main is always a close possiability? or is that what what you mean? and please don't ask me to clearify it because when i reread the question my first thoughts are stern is right and port is up.
the northu cd, which i suggest to all, clearly sows film of real boats in real wind and the jib absolutely jibes first. also the footage is a perfect supplement to don guilette's excellent material.
Prevent what?
What does a preventer do? How is it rigged? How big a steering error does it take to gybe "accidentally"? What possesses people to try to drive on the slowest point of sail?
What does a preventer do? How is it rigged? How big a steering error does it take to gybe "accidentally"? What possesses people to try to drive on the slowest point of sail?
Prevent a jibe
Attach mid boom and to a cleat midships with a quick release. Wind shifts usually cause accidental jibes. Sea motion can also cause a jibe. Moving down the face of a wave faster than the wind is blowing. Tim R.
Attach mid boom and to a cleat midships with a quick release. Wind shifts usually cause accidental jibes. Sea motion can also cause a jibe. Moving down the face of a wave faster than the wind is blowing. Tim R.
depends
The jib is first if the jibe is because of the wind because the weight of the boom causes resistance. The main is concurrent and faster if the jibe is by wave because the wave will move the boat and that will cause a jerk of the boom and the weight of the boom will increase the swing. So, it depends
Gotta hate that word. Get something (a preventer) to tie down the boom and your safe.
The jib is first if the jibe is because of the wind because the weight of the boom causes resistance. The main is concurrent and faster if the jibe is by wave because the wave will move the boat and that will cause a jerk of the boom and the weight of the boom will increase the swing. So, it depends
Gotta hate that word. Get something (a preventer) to tie down the boom and your safe.
One for Mythbusters ...
What conditions must exist to cause an accidental gybe? Sailing by the lee? (Why would you do that?) Violent boat motion that causes the boom to swing over due to inertia? What wind speeds? What true wind angles? What apparent wind angles? After you have thought out the conditions required, try to make a case for using a preventer. I cannot.
What conditions must exist to cause an accidental gybe? Sailing by the lee? (Why would you do that?) Violent boat motion that causes the boom to swing over due to inertia? What wind speeds? What true wind angles? What apparent wind angles? After you have thought out the conditions required, try to make a case for using a preventer. I cannot.
i have no idea on what motivates people to sail dead downwind, but this piece of informaion came from northu's instruction on purposeful jibes. now i know that when my jib starts fluttering, it's time to act, and wanted to share this. i already use a preventer on long reaches but do not rig it for just tooling around. by the way, the helm feels awful dead downwind.
I agree ... DDW is silly
As I'm sure you know and the North U stuff confirms. Running is slow and usually uncomfortable. As soon as you are not running, the chances of an "accidental" gybe are very small. My feeling is that people that do not understand what causes the gybe, tend to look to preventers and boom brakes. In light air, the fastest course downwind puts the apparent wind about on the beam. There is no way that a sober skipper has an "accidental" gybe from a beam reach. Somewhere in the 12-16 knot TWS range the fast course puts the AW into the 140-155 degree range. What does it take to gybe from that point of sail? A instant 30-35 deg wind shift? In winds 18+ the fast course is deep, 170-175 deg. Who has someone at the helm under those conditions that cannot hold a course? In 20 true a C30 has a downwind VMG of 7.082 knots, BTW = 175, BAW = 172 if you come up 15 degrees to make the boat gybe proof, you have a VMG of 6.881 knots (more than 97% of the best downwind speed). I just don't get it. The only time an accidental gybe is close to the optimum downwind course is in heavy air. One accidental gybe will loose much more time than the 3% drop in boat speed from sailing a more controllable angle. For 3% increase in boat speed in heavy air I need a preventer? No thanks, I'll leave the preventers to you hot rod racer types that need that 3%.
As I'm sure you know and the North U stuff confirms. Running is slow and usually uncomfortable. As soon as you are not running, the chances of an "accidental" gybe are very small. My feeling is that people that do not understand what causes the gybe, tend to look to preventers and boom brakes. In light air, the fastest course downwind puts the apparent wind about on the beam. There is no way that a sober skipper has an "accidental" gybe from a beam reach. Somewhere in the 12-16 knot TWS range the fast course puts the AW into the 140-155 degree range. What does it take to gybe from that point of sail? A instant 30-35 deg wind shift? In winds 18+ the fast course is deep, 170-175 deg. Who has someone at the helm under those conditions that cannot hold a course? In 20 true a C30 has a downwind VMG of 7.082 knots, BTW = 175, BAW = 172 if you come up 15 degrees to make the boat gybe proof, you have a VMG of 6.881 knots (more than 97% of the best downwind speed). I just don't get it. The only time an accidental gybe is close to the optimum downwind course is in heavy air. One accidental gybe will loose much more time than the 3% drop in boat speed from sailing a more controllable angle. For 3% increase in boat speed in heavy air I need a preventer? No thanks, I'll leave the preventers to you hot rod racer types that need that 3%.
yup, and the more confused the sea, the more i make it my business to sail off the wind to prevent accidental jibes. i'm just trying to share something i learned.
And a good tip it is!
Knowing that the jib will telegraph the gybe is good information. Put in other terms, if you sail high enough so the jib does not collapse or gybe, you are in no danger of the main gybing "accidentally". In 40+ years of sailing I've never had a gybe that wasn't helmsman induced. I've also seen a number of booms bent or broken due to improper vang and or preventer usage. Try as I might, I just cannot recall ever needing or wanting a preventer.
Knowing that the jib will telegraph the gybe is good information. Put in other terms, if you sail high enough so the jib does not collapse or gybe, you are in no danger of the main gybing "accidentally". In 40+ years of sailing I've never had a gybe that wasn't helmsman induced. I've also seen a number of booms bent or broken due to improper vang and or preventer usage. Try as I might, I just cannot recall ever needing or wanting a preventer.
Preventers
Ocean sailors use boom preventers a lot. The swell rolls the boat so much the boom is almost thrown across by the motion especially in relatively light winds. Gybing shouldn't happen but after several days of downwind sailing, during the night the wind shifts another 10 or 20 deg....and the boat rolls a bit more....... I rig the preventer from the end of the boom to the bow with a snap shackle to the boom. Easy to relase when you do need to gybe. I also only use a 6 mm line so it would break if the sail did gybe. Come on. Enjoy the sailing as well as the calcs!
Ocean sailors use boom preventers a lot. The swell rolls the boat so much the boom is almost thrown across by the motion especially in relatively light winds. Gybing shouldn't happen but after several days of downwind sailing, during the night the wind shifts another 10 or 20 deg....and the boat rolls a bit more....... I rig the preventer from the end of the boom to the bow with a snap shackle to the boom. Easy to relase when you do need to gybe. I also only use a 6 mm line so it would break if the sail did gybe. Come on. Enjoy the sailing as well as the calcs!
I agree, good tip
But where I sail and race there are some high bluffs and our race courses inevitably take us close to docked or moored tankers. I have seen 90 degree wind shifts in a blink of an eye. A preventer allows me and my crew to feel safer when we need to go DDW. It also allows me to get the most out of my Genoa when using the whisker pole. And you can ask any racer who races in a confined bay, you will need to go DDW at some point. Tim R.
But where I sail and race there are some high bluffs and our race courses inevitably take us close to docked or moored tankers. I have seen 90 degree wind shifts in a blink of an eye. A preventer allows me and my crew to feel safer when we need to go DDW. It also allows me to get the most out of my Genoa when using the whisker pole. And you can ask any racer who races in a confined bay, you will need to go DDW at some point. Tim R.
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