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Old 30-03-2013, 17:42   #16
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Re: Broaching - where is the edge?

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Originally Posted by robert sailor View Post
Broaching is often thought of as simply losing control either upwind or downwind. As others have said upwind its a nothing experience, the rudder stalls and the boat heads into the wind and the rudder is good to go again. When your rudder stalls down wind things get a hell of more exciting.
Maybe I should have stipulated broaching to the point of capsizing where everyone goes swimming. What is the maximum degree of heeling before you not only lose control but you lose the boat and is this something one only worries about on a broad reach or running?
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Old 30-03-2013, 17:49   #17
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Maybe I should have stipulated broaching to the point of capsizing where everyone goes swimming. What is the maximum degree of heeling before you not only lose control but you lose the boat and is this something one only worries about on a broad reach or running?
A properly designed boat with weather helm , will not broach when sailing into the wind , all that happens is the boat heels, then spills wind and round ups , all standing. Because the wind is forward of the beam , the sails cannot act as kites and drive collapses.

Downwind a boat can broach , where the rudder stalls and the boat is pinned down by its sails. Its has nothing to do with heeling angle. ( per say) , in essence the rudder becomes unable to retain directional control and the boat ends up beam on to the wind ( and waves ) , at that point the sails act like kites , since they are not aero foils and the since the apparent wind is greater, when stopped , it exerts a force that overcomes the stability of the boat , this is " aided" by the dynamic imbalances caused by the abrupt change in motion and direction, resulting in the boat being pushed on its side to a greater or lessor degree.

Another source is crash gybing. Running with the wind inadvertently on the lee can lead to such a gybe , with the resulting damage and the abruptness can cause directional instability and a broach, common in smaller boats and racing

There are many reason for downwind broaching, some boats cannot retain control if pushed past hull speed ( surfing ) , espcially non fin and spade , other times the " slewing " effect caused by the wave trains can overcome the rudder , or catch an inattentive helmsman. Other times the sail combinations too adventurous for the conditions, or large sails like spinnakers can cause a rhythmic rolling , that leads to broaching. Every boat has a different tolerance and a lot of it is the experience of the Helmsman


Yes of course sailing from a broad reach and deeper , one is always conscious of the event cascade that can lead to a broach , ensuring appropriate sail area, alert helming, wind and wave awareness will ensure that it doesn't happen


Dave
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Old 30-03-2013, 18:25   #18
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Yet another reason it is wise for a sailor to bash about in small boats to learn about sailing. Can broach ten times a day and never upset the galley.
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Old 30-03-2013, 19:23   #19
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Re: Broaching - where is the edge?

The old fisherman who taught me to sail 60 years ago, always told me to make the boat ride comfortable for your body, excessive healing makes for a very uncomfortable ride!! hard to sleep, eat , cook, even going to the head becomes harder! so reefing or bearing off a few degrees makes things a lot mo better !I sorta always figure the comfortable way is the only way! my crews smile a lot more and as Im a cruiser not a racer, a day or two don't mean much in the big picture of cruising!! If it's just to rough to head where I was going Ive been known to change where im going to ! LOL easy peasy We have been sailing this way for a long time and I really think that having done it this way has extended our sailing days by not beating ourselves up trying to go just a little faster!! Just my 2 cents
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Old 30-03-2013, 19:51   #20
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Re: Broaching - where is the edge?

I match up virtually together with bobconnie... when my kids were young, they were always hollering, 'put the rail under, Dad!' but not the most comfortable point of sail. I found that as we pressed our old Ingrid sailing upwind, we would start spill the wind out of the sails as we heeled over even with every thing up. It was only racing off the wind under a spinnaker run that rounding up in a seaway became problematic. Of course, we were always overpowered under those circumstances and did ship a fair amount of green water aboard but it was all fun and we didn't lose anyone important overboard.
When you are cruising, it is all about safety and comfort so forget about trying to press the boat beyond those parameters. Have fun out there... cheers, Phil
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Old 30-03-2013, 22:36   #21
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Re: Broaching - where is the edge?

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You folks are so smart...that's why I come here. Should have figured your answers would depend on point of sale. I was generally thinking anything from a beam reach to close hauled.

Is the consensus that one cannot broach while sailing close hauled in steady winds and relatively calm seas no matter how much the boat heels?
"Cannot" is a big word, but my take on this is that, for all practical purposes, broaching is not really applicable when sailing hard on the wind.
(see end of this post for one class of exception)

To me, there's a hidden but crucial element in broaching, which is the inevitable and powerful tendency of the sailboat hull to lean to the outside when slewing rapidly through a significant course change.

This arises from several factors, the chief one being centrifugal force. This acts on the centre of mass, which is above the centre of lateral resistance (the latter being, crudely speaking, the point underwater where you'd attach a towline if you wanted to drag the boat sideways without heeling it or yawing it.) The offset acts as a lever arm for a heeling moment (twisting force), regardless of the sails or rig.

This heeling tendency can be demonstrated even when motoring in a flat calm, by initiating a hard turn of longish duration at hull speed.

The good thing about being overpowered, sailing closehauled, is (as others have implied) that the portion of the heeling forces arising from the sails automatically starts to diminish as soon as the boat slews maybe five degrees upwind. *

Whereas on a reach (even a beam reach - because the mainsail is technically 'oversheeted' because the stays are in the way of the boom)
the boat has to round up through a much bigger angle, before the sails become 'undersheeted and those heeling forces start to ease.

Especially true if sailing downwind.

So the course change when overpowered on a reach or run becomes more severe and prolonged, which makes the boat heel further, which in turn increases the slewing tendency, so you have a classic 'positive feedback' or runaway situation.

And that's a classic broach ... at least, to my way of thinking.

*(Rare exception which can generate an upwind broach:

If sailing a small, fast, tender boat closehauled, it might slew fast enough when suddenly overpowered to create a "virtual windshift" in the apparent wind, due solely to slew, which makes the headsail stay full because -- and while -- it's being rotated rapidly into the eye of the wind. This will keep the boat heeled over for longer (and through a bigger course change) than you'd normally expect when overpowered, sailing upwind.

If such a boat is wearing a biggish headsail for the breeze, and either a shallow-draft rudder or a fat bum, it's possible -- even if the mainsail is 'dumped' -- to "broach" so hard as to be 'put about' onto the other tack, in territories prone to exceptionally severe 'bullets' of wind.

But this exception is included only for the sake of completeness regarding the word "cannot": I don't expect people reading this to encounter such a circumstance in practice -- or, if they do push such a boat so hard in conditions like this, to be surprised and puzzled by it)
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Old 30-03-2013, 22:48   #22
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Re: Broaching - where is the edge?

I think the OP's analogy with driving in gravel is a helpful one.

Those who push the limits as brash youngsters end up better equipped in later years when circumstances beyond their control deprive them of the gift of traction.

I'm not advocating pushing the limits, just saying that for some people, some day, a situation might arise where that understanding might help. And if you can gain that understanding indirectly -- while that's not exactly the same sort of understanding -- it might still be worthwhile.

I think if the OP goes away reassured that he's unlikely to broach while sailing to windward, he can get on with reducing sail without being disabled by trying to prevent something happening in the meantime which is unlikely to happen.

A useful way of temporarily easing the heeling problem when hard on the wind, is to oversheet (flatten excessively) the headsail, while undersheeting the mainsail --

to the point that, when on course, the front half of the mainsail is in reverse camber. (sometimes called a "fisherman's reef")

This is due to "detached flow" on the lee side, arising from the backwind from the oversheeted headsail, which only reattaches and creates heeling forces when it gets part way along the sail.

This is also worth doing when preparing to reef the main: because the mainsail is doing little work, the person (or technology item) on the helm will not throw a wobbly when you dump the main in order to reef it.
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Old 30-03-2013, 23:23   #23
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Re: Broaching - where is the edge?

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Maybe I should have stipulated broaching to the point of capsizing where everyone goes swimming. What is the maximum degree of heeling before you not only lose control but you lose the boat and is this something one only worries about on a broad reach or running?
In flat water it's almost impossible, on anything with a proper ballast keel, to 'capsize' as a result of broaching.

I vividly recall once broaching in a 20' stub keel, offshore-capable centreboard boat. We laid down and slewed so fast, hard and far that the scenery was actually blurred.

We did not go swimming. That's the one take-away message from this story, you needn't read any further.

But for anyone curious:

The trailing edge of the mainsail slewed across the sea as though a mad genius was spreading butter with a cook's knife.

After traversing most of the surrounding horizon, the boat popped up heading into the (new) true wind direction

It had followed us at least half way round while we were broaching.

Mercifully there was still just enough steerage way to bear away hard, in order to instantly fill the sails again, because the rig was already shaking like a wire-haired terrier attempting to pass a brick.

No bigger boats were broaching ... but that's because in conditions so flukey, it's simply not viable for them to put up any sail: because a stiffer boat stands up to the wind for longer, there's a fair chance they'll either blow out the sails or carry away the rig.

I should explain that this was in sheltered waters: the Marlborough Sounds, NZ - which in certain locations on a good day could serve up stronger bullets from more directions at once, some say, than the Patagonian channels...

It's not so bad now, partly I guess because many hills which were bare are now forested plantations, partly because of changing weather patterns. But it's still a rare thing to see a boat much over 36' wearing sails in any breeze with a westerly component.
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Old 31-03-2013, 03:13   #24
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Re: Broaching - where is the edge?

"how much heeling can a modern fin keel sailboat...tolerate without broaching?"

Depends on your definition of broaching, doesn't it?

If you call "I can stand on the side of the mast" broaching, that's one measure, about 90 degrees of roll. If you don't call it a broach until the masthead is in the water, a bit more, maybe 100-110 degrees.

In any case, you are simply abusing the boat and not sailing efficiently if you've got more than 10-20 degrees of heel on it. Fun is all well and good, but a boat is not a bumper car, if the object of your sailing is "WHEEE!" then by all means, keep going until you reach the capsize point. There's one of those for each specific boat too.

For a keelboat, as opposed to a multihull trying to lift one out of the water.
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Old 31-03-2013, 07:37   #25
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Re: Broaching - where is the edge?

Experience with dingy sailing is a good thing as small boats are harder to break and cheaper to repair. Sailing Lasers are a good example of downwind instability...not to mention the dreaded death roll when sailing directly down wind and hoping the eventual wipe out doesn't include injury.
My new choice of boat should not be heeled more than 15 degrees and never sailed directly down wind in any heavy wind to avoid uncontrollable instability. A better choice of boat for the "WHEEE" factor is probably a Windsurfer or kite board as when things get out of hand, let go and try not to land on the equipment. No broaching is ever a factor but getting scared is.
Racing big boats, in my opinion, is sometimes dangerous and costly as pushing displacement hulls to the limit often include capsize, injury and very costly damage...cruising on the other hand includes safety, comfort and reefing when the time comes. Scaring the crap out of the crew just isn't cool.
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Old 31-03-2013, 07:56   #26
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pirate Re: Broaching - where is the edge?

I'm wondering if the OP is confusing Broaching with Knockdowns which are more common when heading into wind... ie; caught by a sudden squall with no time to reef..
Well heeled and going like the clappers when you hit an acceleration zone and go over...
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Old 31-03-2013, 08:14   #27
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Re: Broaching - where is the edge?

Is the OP confusing rounding up with broaching? Two different things but with some similar and related causes (i.e. too much sail and/or speed for existing conditions) and effects (i.e. uncontrolled boat getting sideways to intended course).The physics too are different as some have pointed out above.
A well designed boat will give feedback to the alert helms person as to when things are getting a little squirrelly,and this is where big water experience will allow speed to be carried while us lesser mortals are going for the reefing gear.
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Old 31-03-2013, 09:02   #28
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Re: Broaching - where is the edge?

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Is the OP confusing rounding up with broaching? Two different things but with some similar and related causes (i.e. too much sail and/or speed for existing conditions) and effects (i.e. uncontrolled boat getting sideways to intended course).
No but I have obviously confused broaching with capsizing or knock downs. Thanks to everyone who has responded here and additional reading on my own I now understand that broaching does not necessarily result in capsizing.

In hindsight my original question probably should have been more along the lines of "how much heeling can a typical fin keel boat under 32' tolerate on a beam reach or close reach without capsizing (or knock downs?)."

I get it that broaching while running with the wind or on a broad reach is a more serious question and I greatly appreciate all the wonderful feedback I've gotten here.
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Old 31-03-2013, 11:48   #29
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Re: Broaching - where is the edge?

generally, anything over 20 degrees will mean you will lose speed, the boat will become harder to handle the the ride will be less comfortable.

staying at under 20 degrees will get you there fastest.

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Old 31-03-2013, 11:58   #30
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Re: Broaching - where is the edge?

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I'm wondering if the OP is confusing Broaching with Knockdowns which are more common when heading into wind... ie; caught by a sudden squall with no time to reef..
Well heeled and going like the clappers when you hit an acceleration zone and go over...
Thanks for the clarification.
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