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Old 16-10-2012, 09:19   #31
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Re: Rounding Up... Other Tactics & Questions

dump main.(let it out)
or
turn into wind, placing boat into irons.
OR
if no one is freaked out by it--keep on going.
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Old 16-10-2012, 10:58   #32
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Re: Rounding Up... Other Tactics & Questions

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Originally Posted by cfarrar View Post
What you say is true in a moderate breeze. You tension the vang to flatten the sail, and you play the main sheet. However, in stronger breeze you need to ease the vang to depower. Picture this: you're reaching in a strong breeze (beam reach to a broad reach), you've already used the backstay, outhaul, halyard, and cunningham to flatten the sail. The mainsheet is already out as far as it can go. When a big puff hits the boat the only control that will quickly depower the main is the vang. You ease the vang, the boom rises, the leech twists to leeward, and the sail instantly depowers. In a gnarly puff you should do this before the boom hits the water. When racing you need someone with their hand on the vang in these conditions. If you're singlehanding in such conditions and you know that you won't be able to quickly get to the vang, you should reef or sail a lower point of sail; also, you can ease the vang pre-emptively, creating a lot of twist and depowering the sail.

You're absolutely correct that you need to be careful easing the vang on a run, because while the vang powers up the sail it also stabilizes the sail plan laterally. Picture this: you're running in 20 knots of true breeze, with the jib or spinnaker poled out to windward. A nasty puff hits, and you blow the vang. Whoops! The boom rises, the leech twists, and the formerly balanced boat - having lost the pressure on the most leeward part of the main sail (the leech area) - immediately rolls to windward, creating lots of lee helm. The boat heads off, and you crash jibe, probably into a broach. This is why a race crew on a downwind run needs to keep a hand on the vang. They ease the vang if the boat rolls to leeward and threatens to bury the boom in a wave, but then they put the vang tension back on to keep the boat from rolling erratically to windward.
The gist of my response was single handing. Vang on minimizes wear and tear and keeps the sail off the spreaders for the most part. If I'm overpowered I will reef. I see so many boats without a proper vang. I always instruct that having a vang is not just another sail adjustment, which many sailors do, but a very important safety feature. Keeping the boom under control is a important concept to impress. Twist in light air is another concept which requires a slack vang but we are talking a breeze. I would urge those who sail tender boats to practice setting a reef when the wind pipes up. It really makes all the difference. Helps to keep jittery crew relaxed and wanting to crew the next breezy day.
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Old 16-10-2012, 11:09   #33
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Re: Rounding Up... Other Tactics & Questions

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Originally Posted by hpeer View Post
I surly need to read this thread more closely. Had a similar incident with the wife, with a wrinkle or two.

Two am, motor sailing, I'm asleep on setee. Center cockpit boat has a tiller pilot on an aries wind vane to a permanetly fixed tiller so I need to go aft to pop out the chain and disconnect pilot. Also have a Dutchman boom break set, I am frequently solo so this is a common set up.

What I think happens is the wind builds gradually, wife does not notice or correct, autopilot tries to keep heading. Get a good puff of air, she rounds up, wife alarm goes off EXACTLY as in OP.

I'm out of the bunk, into cockpit, dump motor, let main go, Dutchman has it (****), go back and pop chain off auto pilot, all is calm, maybe 20 seconds.

I should have popped the Dutchman boom break to release the boom.

At that instant, with a freaked crew, it is challanging, at least to me. We need to do better.

I was sleeping all standing so had my harness and tether on already, jack lines set, which was good for trip back to tiller.
You SHOULD have tucked in the double reef before dark, especially when motor sailing.
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Old 16-10-2012, 11:20   #34
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Re: Rounding Up... Other Tactics & Questions

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Originally Posted by Dockhead View Post
All very true, but many boats will have the boom out beyond the limits of the traveller on a beam reach. At that point, the mainsheet ceases to control the leech of the sail and the vang comes into play.
My boat sails fastest on a beam reach, with someone actively tending the vang. Sheet it in for the lulls (powers up the head of the sail) and sheet it out (spilling at the head) in the gusts, when the weather helm gets too much. We leave the main sheet alone. This technique will have her going like the clappers (well, fast for a 31ft Bristol, anyway.)

"What you say is true in a moderate breeze. You tension the vang to flatten the sail, and you play the main sheet. However, in stronger breeze you need to ease the vang to depower. Picture this: you're reaching in a strong breeze (beam reach to a broad reach), you've already used the backstay, outhaul, halyard, and cunningham to flatten the sail. The mainsheet is already out as far as it can go. When a big puff hits the boat the only control that will quickly depower the main is the vang. You ease the vang, the boom rises, the leech twists to leeward, and the sail instantly depowers. "

This is very much my experience with the Bristol, once the wind is 20 kts plus. Some people like to have the vang line long enough to reach the helm, and in a cam cleat, so that it can be easily (and rapidly) adjusted.

Again, when you are in a beam reach and a gust hits you, dumping the vang has an instant depowering effect.
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Old 16-10-2012, 17:53   #35
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Re: Rounding Up... Other Tactics & Questions

It is important to try and keep apples to apples comparisons. The main sail has a lot of controls and they are used on different points of sail and in different wind conditions and sea states in different ways. In my first example I suspended discussion of backstay and cunningham as not all boats have these controls. Suffice to say if you have these controls you definitely should learn how to use them. When I was trimming J-24s I had a question about "sail inversion" - I had the opportunity to sail with one of our top skippers and he showed me what it looks like.

Anyhoo - Yes a flat sail is "depowered" in the sense of aerodynamics. Thnk about airplane wings you have seen.

A slow airplane that has high lift has a "fat" wing. A fast airplane has a thin wing. Because of bernoulli the fat wing will generate more lift at lower speeds and the thin wing will need higher speeds to generate the same lift.

The fatter wing will have more drag. The fatter wing will generate its lift over a wider range of (relative) wind angles. You see STOL aircraft going slow and high deck angles because that fat wing can handle more alpha.

Guess what? All that applies to a sail. A flat sail has less drag, allows a smaller steering angle but generates the same lift as a fat sail as long as the wind speed is higher.

If you have lumpy seas, good wind speed you generally want a "fatter" sail so you can steer up and down the lumps and accelerate the boat better - remember a fatter wing generates more lift at slower speeds - think of is as a "lower gear" in a car.


Quote:
Originally Posted by Dockhead View Post
If you're near the edge of the wind speed envelope for the amount of sail you have up, it becomes crucial to have the main in its least full shape, so you want full halyard tension to move the draft forward, and you want plenty of vang and outhaul tension to keep the sail relatively flat.
<snip> I now reef quite a bit later than I used to, having figured this out, and gusts don't bother me nearly so much.
This is true and it is part of decision making. Flattening the sail, increasing backstay tension etc. all depower the sail - at some point you have to decide if the increase in wind speed is persistent and a sail change is in order - remember a very flat sail means the helm must sail very tight angles in order not to stall the sail. You also have to consider heel which increases leeway which reduces VMG.

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Originally Posted by donradcliffe View Post

A quick primer on main trimming--as the wind picks up, you use more mast bend to flatten and depower the main. Bending the mast tends to loosen the leach of the sail, reducing weather helm and increasing boat speed. It also makes the draft move aft, which is why more cunningham is required to move it back forward.
Yup - Adding backstays and cunningham increases the number of tools in the trim bag.

This one confused me for a long time - If I loosen the leech by adding backstay how does that make the sail "flat" - I forgot that as the top of the mast comes back the belly of the mast goes forward "pulling in" the middle of the chord. Actually the tension is between the clew and the middle of the mast - when the sail "inverts" you get big noticeable diagonal wrinkles in the bottom half of the sail - you are definitely overpowered in terms of wind speeds...

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Originally Posted by bewitched View Post
Flatten the main definitely, but leave the vang off. A vang strapped on hard will inhibit your ability to depower a main when reaching. It will hold the boom down and therefore not allow you to twist off the top of the sail

As a rough guide, there is no need to use the vang at all unless the boom is outside the extents of the traveller. It is very much an off-wind sail control
When reaching the vang controls the sail shape and should be on far enough to create the necessary shape - so it's not an on or off proposition.

When downwind I tell the mast man (the vang controller) that the vang is the emergency brake. The only way to depower a spinnaker is blow the sheet or guy. Then hell has broken loose (usually) - the first bail out under spinnaker is blow the vang and the main immediately depowers.

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Originally Posted by Tar34 View Post
Sorry, easing the vang is exactly the the wrong thing to do in breeze. The vang is essential for keeping the main flat and in control. Also, if sailing down in the puffs as the original poster offered as a strategy, the danger of an accidental jibe is increased without a vang.
My presumption is this is when sailing downwind and the above advice stands.

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Originally Posted by cfarrar View Post
What you say is true in a moderate breeze. You tension the vang to flatten the sail, and you play the main sheet. However, in stronger breeze you need to ease the vang to depower. Picture this: you're reaching in a strong breeze (beam reach to a broad reach), you've already used the backstay, outhaul, halyard, and cunningham to flatten the sail. The mainsheet is already out as far as it can go. When a big puff hits the boat the only control that will quickly depower the main is the vang. You ease the vang, the boom rises, the leech twists to leeward, and the sail instantly depowers. In a gnarly puff you should do this before the boom hits the water. When racing you need someone with their hand on the vang in these conditions. If you're singlehanding in such conditions and you know that you won't be able to quickly get to the vang, you should reef or sail a lower point of sail; also, you can ease the vang pre-emptively, creating a lot of twist and depowering the sail.

You're absolutely correct that you need to be careful easing the vang on a run, because while the vang powers up the sail it also stabilizes the sail plan laterally. Picture this: you're running in 20 knots of true breeze, with the jib or spinnaker poled out to windward. A nasty puff hits, and you blow the vang. Whoops! The boom rises, the leech twists, and the formerly balanced boat - having lost the pressure on the most leeward part of the main sail (the leech area) - immediately rolls to windward, creating lots of lee helm. The boat heads off, and you crash jibe, probably into a broach. This is why a race crew on a downwind run needs to keep a hand on the vang. They ease the vang if the boat rolls to leeward and threatens to bury the boom in a wave, but then they put the vang tension back on to keep the boat from rolling erratically to windward.
Great description!

However my experience on what happens when the vang is blown can depend on when it is blown. Usually the boat is already rounding on it's way to broach. The spinnaker is moving to the beam. If the vang is late the driver may have to steer down - number one rule is get back under the spinnaker. If too late the lateral forces of the spinnaker will overpower the rudder and the only person that can save the boat is the spin trimmer. All hell has truly broken loose and at this point everyone is probably just hanging on to the rails waiting for the boat to stand back up- LOL

You are right that if sailing deep everyone needs to be on their toes. Helm, spinnaker trimmer(s) mastman (vang) and main trimmer. The two bad choices are broach or crash gybe. The good outcome is the team gets the boat back under the spinnaker and the vang comes back on.

Quote:
Originally Posted by MarkSF View Post
My boat sails fastest on a beam reach, with someone actively tending the vang. Sheet it in for the lulls (powers up the head of the sail) and sheet it out (spilling at the head) in the gusts, when the weather helm gets too much. We leave the main sheet alone. This technique will have her going like the clappers (well, fast for a 31ft Bristol, anyway.)
I have had lots of discussions about vang sheeting but never actually did it or practiced it. Most keelboats I have been on the vang is a mastman control or piano control at best.

I always thought it was more of a performance beach cat (nacras, F16 etc) and I missed that phase of my sailing career.

I think it would take great skill to provide the right about of twist in the gusts and lulls.
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Old 16-10-2012, 18:18   #36
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Re: Rounding Up... Other Tactics & Questions

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Originally Posted by Ex-Calif View Post
I have had lots of discussions about vang sheeting but never actually did it or practiced it. Most keelboats I have been on the vang is a mastman control or piano control at best.

I always thought it was more of a performance beach cat (nacras, F16 etc) and I missed that phase of my sailing career.

I think it would take great skill to provide the right about of twist in the gusts and lulls.
Agreed. I can't help but feel that vang sheeting is for small boats such as racing dinks. On my boat the vang leads to a winch and really can't be operated by hand when under load--there's just too much pressure. In fact, it's one of two sail controls--the other being the outhaul--where we specify five wraps rather than three. On my last racing boat we had a hydraulic vang, and it took a good deal of pumping to affect sail shape. You could blow it in a hurry, but....
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Old 16-10-2012, 18:56   #37
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Re: Rounding Up... Other Tactics & Questions

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Agreed. I can't help but feel that vang sheeting is for small boats such as racing dinks. On my boat the vang leads to a winch and really can't be operated by hand when under load--there's just too much pressure. In fact, it's one of two sail controls--the other being the outhaul--where we specify five wraps rather than three. On my last racing boat we had a hydraulic vang, and it took a good deal of pumping to affect sail shape. You could blow it in a hurry, but....
The vang is a Garhauer rigid one. Not sure of the reduction, but I've had no problem adjusting it on a beam reach in 25 kts of wind. The lever clutch is also a Garhauer. Mind you, the main is only 200 sq ft. On a larger boat the load would be too high.
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Old 16-10-2012, 19:01   #38
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Re: Rounding Up... Other Tactics & Questions

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Flatten the main definitely, but leave the vang off. A vang strapped on hard will inhibit your ability to depower a main when reaching. It will hold the boom down and therefore not allow you to twist off the top of the sail

As a rough guide, there is no need to use the vang at all unless the boom is outside the extents of the traveller. It is very much an off-wind sail control
Sorry, simply incorrect. I'd much rather have the vang ON when it starts to get windy. Can always pop it later. A full main is a powerful main, sometimes not the best thing for when it starts to get windy.

We use the vang a lot when going upwind.
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Old 16-10-2012, 19:14   #39
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Re: Rounding Up... Other Tactics & Questions

If you are lake sailing in your Hunter it is highly unlikely that your boat could get knocked down in anything short of a hurricane or microburst. It might scare the heck out of you, but your boat will heel hard and round up. The more you sail your boat, the more you will learn when to reef. For me, if I see white caps I start reducing sail.

Lake sailing has lots of quirks. You can't always see the wind coming on the water in time because the distances to land are short. It can blow on one side of the lake and not the other.

Practice heaving to with your boat. My wife was amazed at how we could "park" the boat in snotty conditions. It's easy too.....round up, back wind the jib, release the main, and turn the wheel hard over into the wind. I can do it in about 10-15 seconds easy.

Help her understand that the boat is not going to tip over. It might get scary, but your boat can take more than you can.
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Old 16-10-2012, 19:18   #40
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Re: Rounding Up... Other Tactics & Questions

Well Stu, we all do things differently. I NEVER use a vang upwind. Leech control exclusively on backstay and main sheet.

Vang on powers the main because it closes the leech

Vang off de-powers the main because it opent the top leech and twists off the sail.

But opening and closing the leech when close-hauled can be achieved by using the mainsheet and/or backstay. Much easier surely?
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Old 16-10-2012, 19:30   #41
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Re: Rounding Up... Other Tactics & Questions

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Sorry, simply incorrect. I'd much rather have the vang ON when it starts to get windy. Can always pop it later. A full main is a powerful main, sometimes not the best thing for when it starts to get windy.

We use the vang a lot when going upwind.
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Well Stu, we all do things differently. I NEVER use a vang upwind. Leech control exclusively on backstay and main sheet.

Vang on powers the main because it closes the leech

Vang off de-powers the main because it opent the top leech and twists off the sail.

But opening and closing the leech when close-hauled can be achieved by using the mainsheet and/or backstay. Much easier surely?
This may be an apples and oranges situation and I am not sure you guys are disagreeing.

Upwind (boom over traveler) the vang is usually snug - this is so no vang adjustment is necessary if the main has to be sheeted out. There is little chance of the need to blow the vang to reduce power in this state. Dropping traveler usually does it. If not the main is then sheeted out, vang maintaining sail shape and further depowering until the main luffs.

Reaching - wind forward of the beam the same applies. As long as you can luff the main with mainsheet or traveler vang is not necessary.

To reiterate - you have complete power control with traveler and main when the wind is forward of the beam. In this case you actually should have spent some time on twist - that is getting the upper and lower tells to fly together. If the twist is wrong the upper and lower parts of the sail will stall at different angles and that is inefficient.

If you drop traveler and/or main going up wind for a gust - you don't want to spend any time when powering back up getting the right twist back in.

Once the wind is abaft the beam the vang becomes the "urgent" depowering option.

Of course in this condition the sails have been adjusted for downwind sailing. This would include a combination of backstay eased, outhaul eased, cunningham eased, vang adjusted to optimum twist.

When I say optimum twist I mean that the spinnaker always flies full, if conditions are strong you may need the main permanently depowered a bit on the downwind run unless you are a planing hull. Twist spills mainsail pressure.
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Old 16-10-2012, 21:04   #42
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Re: Rounding Up... Other Tactics & Questions

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This may be an apples and oranges situation and I am not sure you guys are disagreeing.
I think we are, but nice of you to keep things nice

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Upwind (boom over traveler) the vang is usually snug
I personally don't snug the vang upwind as it will hold the boom down should I want to twist off the top leech

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Originally Posted by Ex-Calif View Post
There is little chance of the need to blow the vang to reduce power in this state. Dropping traveler usually does it.
Again, personally I tend to use mainsheet rather than traveller. Twisting off the top leech will maintain height, dropping the traveller may not

Here's a few pics to show how I think about controlling the top leech.

First pic: Upwind: Boom up on the centre line, vang slack, top leech being controlled with backstay and mainsheet. We have an electric backstay so easy. Cruising boats will favour main sheet more.

Second Pic (black sail): Reaching (it says A3 on the sail, but it doubles as our Code 0). Note that the boom is still pretty high on the boat and the top leach is primarily controlled by the main sheet and masses of twist off to keep the slot. Dropping the boom here just closes the slot. At this point of sail in any breeze it would be almost physically impossible to control the top leech with the vang. This boom angle will be achievable for most boats with a traveller.

Third Pic: (white sail): Running with A2. Note the boom has now moved outside the extents of the traveller. The vang is now used to hold down the boom - easy to adjust as there is very little load
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Old 16-10-2012, 21:13   #43
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Re: Rounding Up... Other Tactics & Questions

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Vang off de-powers the main because it opent the top leech and twists off the sail.
How? A deeper mainsail is more powerful. How you do dat?
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Old 16-10-2012, 21:15   #44
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Re: Rounding Up... Other Tactics & Questions

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The vang is a Garhauer rigid one. Not sure of the reduction, but I've had no problem adjusting it on a beam reach in 25 kts of wind. The lever clutch is also a Garhauer. Mind you, the main is only 200 sq ft. On a larger boat the load would be too high.
Some of those Garhauer rigid vangs have a 20:1 purchase. That's impressive, and will certainly facilitate hand-over-hand usage for most boats owned by CF members. However, 20:1 is too slow to be useful for vang sheeting. Gotta pull in 10 feet of line to get 6 inches worth of sheeting. Forget about using that to prevent a round-up.

And you're right, a 200 sq ft main is, ahem, smallish. My main runs 500 sq ft, and at that point taking the vang straight to a winch makes a lot of sense.
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Old 16-10-2012, 21:48   #45
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Re: Rounding Up... Other Tactics & Questions

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How? A deeper mainsail is more powerful. How you do dat?
The vang doesn't control the depth of the sail. Outhaul sets the depth of the draft. Cunningham/halyard sets the position of the draft.

As the wind picks up and you heel too much, first reduce the draft by flattening sail with outhaul. As the wind continues to build, move the draft forward with cunningham. As the wind builds further, twist off the top leech with mainsheet. More wind building and its a reef.

The vang has nothing to contribute to this process - all the vang can do is pull down the boom and close the top leech....and upwind you are using the main sheet to achieve this goal.
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