Boom Furling?

[mocap1]

Ray,

You are correct that the boom outhaul controls, the fullness of the main. Tensioniong the foot reduces the draft, at least in the lower half of the sail.

However, downhauling the Cunningham does not flatten the sail. It's purpose is to move the location of the maximum draft forward, which is what you want to do to get a more effective airfoil shape as the wind velocity increases. This works because of the orientation of the weave of the sailcloth with respect to the luff, something built into the sail by the sailmaker.

With regard to pinching, whether to pinch or foot is a common and constant dilemma to a sailor trying to make good distance to windward.The proper choice depends on a number of factors, such as the helmsman's steering ability, sea conditions, wind conditions, and hull characteristics.

It is my belief, as discussed in the excerpt from Ross that I cited, that in light airs, probably the 2-5 knots he mentioned, you will get there faster by centerlining the boom and sailing higher. Of course as the wind comes up you have to ease the sail to keep the boat on its feet. I don't know the conditions under which Aldair suggests it is better practice to sheet to windward..." to get a better sail shape"

As for the roles of the vang and mainsheet in controlling sail shape we may have only a semantic difference. My point is that when the boom is within the range of the traveller so that the pull of the maunsheet is straight down, the vang does nothing. You are correct in stating that when you sheet out because of increased wind velocity, it is the vang which holds the boom down. If you believe the vang has some effect when the boom is over the traveller, check it out next time you are out sailing.

Further, I don't think the Vega has a bendy boom,as asserted by AldairMort

 

[wso_ornbau]

What an interesting discussion! May I add my 2 cents ?
I´m missing the role of the twist of the main. I think the control of
the twist is the major purpose of the traveller adjustment.
My understanding: Wind velocity is reduced the nearer the sea (or
deck) surface you are (due to friction). If I would climb the mast,
the higher I get the more favourable the (apparent) wind will be.
The main is sheeted according to the apparent wind. Therefore the
twist is adjusted (by means of the traveller position) in such a way,
that the upper part of the main is more open (less sheeted) than the
lower part.
In stronger winds less twist is needed (-> traveller goes to lee)
because the stronger the wind is, the lower the point will be where
the velocity reduction begins.
Controlling flatness by means of the outhaul, shifting the "belly"
forward by means of the Cunningham is basically independent of the
twist control.
This is the way I did it up to now but I´m always willing to
understand it better!
And again: I love this discussion!!!
Lueder
Vega # 1992
Erlangen, Germany

 

[mocap1]

Lueder, I am in agreement with you. My point was that when sailing hard on the wind the and the mainsheet attachment to the boom is over the traveller track, the twist is controlled by the mainsheet and traveller position and the vang is not needed. When you sheet out, for what ever reason, so that the mainsheet attachment is no longer over the traveller track, the vang becomes necessary.

 

[wxt8981]

Hi all.
Hi Mort.

 

[stevebirch2002]

Hi All

I would like to add my bit (again!). I am sure that to sail the Vega
well you need experience, talent, enthusiasm and a Vega!

I have the Vega, I have the enthusiasm, I have a little bit of
experience (12 years on a Vega) but I don't have the talent! To prove
this I was sailing to the IFR (Medway) in 1998 with a F5/6 behind on the
starboard quarter. We were flying along with main and spinnaker when it
was my turn to helm . I took over the tiller and for a few minutes it
was great and then I had the stupidity to look at the wind instrument
(big mistake), it read 25 knots which I quickly calculated that with our
boat speed (7 knots) the wind was blowing at about 32 knots! Now came
the panic and I froze, then broached, then shouted at the crew
(experienced helmsman and a natural sail trimmer) as it was obviously
their fault! The spinnaker was taken down whilst losing a spinnaker
sheet with expensive fitting consigned to the depths. With just the main
up we were still doing our 7 knots which goes to prove you don't need
every inch of sail flying. I learnt a few lessons that day:

1. Don't panic
2. Reef early, it's easier and safer
3. Don't shout and blame the crew as it is usually the skipper's
fault
4. Get some experience in strong winds at all points of sail. Wind
behind you is very deceptive.

Kind Regards

Steve Birch Vega "Southern Comfort" V1703

 

[dduckd6]

Mort..I really enjoy your posts on the Vega.I have only been sailing for about 15years,my first 2 years was on a Vega out of Richmond YC named Touchstone..You are absolutly right..It feels like a real boat..Currently I just have a V222..But hope to own a Vega in the next couple of years..Hope to see you on the bay..If you send your boat name to me I'll be looking at ya..

Again Thanks
Don V222
Sacramento,Ca

"Morton L. Caplan" MortonCaplan@... wrote:
I would take issue with some of Alisdairs statements.

A boom vang, on a boat such as the Vega which has a real traveller located directl;y below the boom, is used only when off the wind. Consider this: The forward end of the boom is attached to the mast such that it can rotate about the aft side of the mast both horizontally and vertically. IT CANNOT MOVE UPWARD. The aft end of the boom is attached to the mainsheet which in turn is connected to the traveller. When sheeted in hard, the end of the boom assumes a position over the traveller. It can translate horizontally a very small amoun, but IT CANNOT MOVE UPWARD. We thus have both ends of the boom prevented from moving upward. Adding additional downward force, such as with a vang, will do nothing to the shape of the sail, and will not move the boom.

In Looking at Sails by Banks and Kenney , an authoritative text, they state: " If the mainsheet traveller had the the same sweeping length of arc as the boom could swing, it would be easy. We could say that all the up and down adjustment of the boom, controlling mainsail leech tension could be the role of the mainsheet........Once outside the the arc of the traveller, the vertical load on the clew must be taken by the vang, and the mainsheet must take over the role of the traveller in presenting the sail to the wind at the right angle"

In Sail Power by Wallace Ross, he states: "....As you sail even further off the wind, you want to set the carriage even further outboard but you have reached the end of the track. At this piont the vang takes over.The vang should be presecured so that when you have to ease the mainsheet to allow the sail to go further outboard, you still have a firm control over the leech."

To get the best performance going to windward, the boom should definitely not be sheeted over center. This is something that is sometimes done in light airs, probably more to give the crew something to do than for any real benefit.

Ross suggests that when going to windward in very light air, 0-2 knots, it is important t have the boom trimmed well out until the boat gains speed, such as in a puff. He says that when the wind is in the 2-5 knot range, the boom '.....should be trimmed to the FURTHEST INBOARD POINT [THE CENTERLINE] and the leech should be relatively tight. (Midship travellers will need to be pulled to windward UNTIL THE END OF THE BOOM IS CENTERLINED"

As the wind increases, the boom should be kept centered until the crew is fully hiked out and the maximum heel is reached. From that point on, the sheet should be eased to keep the boat on its feet.

I have some comments about raking the mast aft, and moving weight forward, both of which can be beneficial under certain circumstances, but I doubt that anyone has read this far, so I will save it for another time.

I have heard it said that differences of opinion make horse races; I guess the same is true of sailboat racing.

Mort

 

[dduckd6]

Mort..I really enjoy your posts on the Vega.I have only been sailing for about 15years,my first 2 years was on a Vega out of Richmond YC named Touchstone..You are absolutely right..It feels like a real boat..Currently I just have a V222..But hope to own a Vega in the next couple of years..Hope to see you on the bay..If you send your boat name to me I'll be looking at ya..

Again Thanks
Don V222
Sacramento,Ca

"Morton L. Caplan" MortonCaplan@... wrote:
I would take issue with some of Alisdairs statements.

A boom vang, on a boat such as the Vega which has a real traveller located directl;y below the boom, is used only when off the wind. Consider this: The forward end of the boom is attached to the mast such that it can rotate about the aft side of the mast both horizontally and vertically. IT CANNOT MOVE UPWARD. The aft end of the boom is attached to the mainsheet which in turn is connected to the traveller. When sheeted in hard, the end of the boom assumes a position over the traveller. It can translate horizontally a very small amoun, but IT CANNOT MOVE UPWARD. We thus have both ends of the boom prevented from moving upward. Adding additional downward force, such as with a vang, will do nothing to the shape of the sail, and will not move the boom.

In Looking at Sails by Banks and Kenney , an authoritative text, they state: " If the mainsheet traveller had the the same sweeping length of arc as the boom could swing, it would be easy. We could say that all the up and down adjustment of the boom, controlling mainsail leech tension could be the role of the mainsheet........Once outside the the arc of the traveller, the vertical load on the clew must be taken by the vang, and the mainsheet must take over the role of the traveller in presenting the sail to the wind at the right angle"

In Sail Power by Wallace Ross, he states: "....As you sail even further off the wind, you want to set the carriage even further outboard but you have reached the end of the track. At this piont the vang takes over.The vang should be presecured so that when you have to ease the mainsheet to allow the sail to go further outboard, you still have a firm control over the leech."

To get the best performance going to windward, the boom should definitely not be sheeted over center. This is something that is sometimes done in light airs, probably more to give the crew something to do than for any real benefit.

Ross suggests that when going to windward in very light air, 0-2 knots, it is important t have the boom trimmed well out until the boat gains speed, such as in a puff. He says that when the wind is in the 2-5 knot range, the boom '.....should be trimmed to the FURTHEST INBOARD POINT [THE CENTERLINE] and the leech should be relatively tight. (Midship travellers will need to be pulled to windward UNTIL THE END OF THE BOOM IS CENTERLINED"

As the wind increases, the boom should be kept centered until the crew is fully hiked out and the maximum heel is reached. From that point on, the sheet should be eased to keep the boat on its feet.

I have some comments about raking the mast aft, and moving weight forward, both of which can be beneficial under certain circumstances, but I doubt that anyone has read this far, so I will save it for another time.

I have heard it said that differences of opinion make horse races; I guess the same is true of sailboat racing.

Mort

 

[wxt8981]

Hi all......

It's fun reading these stories about 'racing' and 'sailing'
a Vega! That gives me the opportunity to add some of my
'experiences'.
I don't think a Vega is a 'slow' boat! I've sailed in quite
a few races and I was ahead of other boats the same
length.I do admit I used to race in a 19 foot daysailer
(Flying Scot) and I can prove this with the many 1st.
finishing trophies.
And then I think a Vega is quite forgiving- I once sailed
all day long with main and spinaker and didn't realize how
much the wind had come up.. she was doing about 7 knots
when I had to jibe (my 10 year old son und my 12 year old
daughter were my crew), when she broached and layed the
mast flat into the water. I was able to release all the
lines, she came up and besides getting a little wet nothing
else happened. ( my children were in the cabin, and I was
wearing a harness, as I always do when in open waters).
What I like to say is... A Vega is a well balanced boat,
and she's quite fast, safe, and I wouldn't change her for
any other boat.
Wilhelm, Vega 257