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Johan Hackman View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Johan Hackman Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2012 at 09:17
Originally posted by Swanji Swanji wrote:

Assuming the correct rig set up, how much back stay do you need to add at various wind strengths? Any thoughts?


Sorry for the late reply to this question.

I always look at the topmost batten do determine the right back stay tension. In light winds it should be curved and in strong winds flat, as should the main sail.

I happen to have taken a few pictures to show what I mean.

First, two pictures of when there is no back stay tension:



No tension on the back stay


The top batten is curved
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Johan Hackman View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Johan Hackman Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2012 at 09:19
Then, two pictures taken at the same occasion with maximum back stay tension. This is how I would trim the sail in a strong wind.


Maximum tension


The top batten is flat
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Peter-Blake View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Peter-Blake Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2012 at 09:53
Thanks Johan for these good example fotos.

I was surprised how much it on your boat effects the profile of the main, on my boat it is definatly not that much. So i did a little photoshopexperiment with yout fotos. How much tension do you put on the backstay? Do you use the winch for it?

I tried the winch sometime ago, But it is easy to overload the backstay!

If it is ok for you Johan, i show my experiemewnt with your foto here. If not let me know and i will delete it.
For the following example I used your fotos for a small .gif file. Both fotos in one small "movie"

BTW: The spreader does not move that much, it is only coming from the stretching of both fotos to get them nearly in same position and the foto is not 100% taken from the same position.


Original Foto from Johan Hackman


Edited by Peter-Blake - 15 August 2012 at 09:55
Blake 370
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Swanji View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Swanji Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2012 at 10:24
Hello Johan and Peter-Blake

Your explanation about how much backstay tension and what to look for is a great birthday present. Thank you Smile

I am about to head off to Croatia in about 10 days time, so I will be sure to use the top batten test and not to be too shy/scared with the backstay in future - from the image, it looks as if you have tensioned the backstay by about a foot!


Onwards and upwards

Nidri, Levkada, Ionian, Greece

Hanse 350 #7, SY Evolution, standard keel, 3YM20 sail drive, 3 cabins, cherry wood interior, teak decks, feathering prop
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samuel View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote samuel Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2012 at 11:15
I am going to have to interject here
If I am reading the pictures correct the woolies on the top batten are all streaming like the lower ones
If I was setting that sail I would have the top batten in a bit tighter so the top wooly was just stalling

Whilst I am putting my foot in it I would not agree with the set of the oppie sail
Of course the angle of the picture may make it look wrong but I would not let the leech of the sail go forward of the mast. OK in light airs it may work but in heavy airs it causes the boat to roll to windward. Not so much on a large boat but a recipe for ending up in the drink on a dinghy
It can cause violent rolling if coupled with a spinnaker
To go back to the vang - it does not need to be hard down when sailing to windward
Current RYA training - i am told- suggests that you move the traveller up to windward, the boom towards the center & concentrate on controlling the twist without the vang.
Obviously the wind strength has a say in how far in or out the boom is setl But if you do not have a traveller then you are stuck & may have to use more kicker etc
Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex
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samuel View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote samuel Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2012 at 11:27
Oh & I forgot
If you tighten the backstay you change the sag in the forestay. That affects the set up of the jib so you need to look at that as well
Difficult to say what you do as it depends on the cut of the jib & how much sag the sailmaker allowed in the first place

That is the fun of a Hanse
It really is a tweakers boat. Some days it flies & some days it goes like an old dog ( due respects to Stampe of course!!!)
Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex
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Johan Hackman View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Johan Hackman Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2012 at 12:45
@P-B: I don't mind at all. In fact, your experiment visualizes exactly what I wanted to show. I never thought of a making a .gif myself.

@Swanji: I am glad my pictures were of help.

@Sam: only the first two pictures show the trim for wind at the time. The second two pictures show the main flattened out the way I would have it in a much stronger wind. The point was only to show how the sail shape changes with back stay tension. However, in the picture with the curved batten (i.e. the shape suitable for the existing wind) the top telltale is stalling.

It took me some time to figure out what you meant with the "oppie sail". You are referring to the picture on the previous page when I am sailing an Optimist, right? It has been noted that you don't approve of my main sail handling some forty years ago.

Johan
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Johan Hackman View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Johan Hackman Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2012 at 12:49
Originally posted by samuel samuel wrote:


To go back to the vang - it does not need to be hard down when sailing to windward
Current RYA training - i am told- suggests that you move the traveller up to windward, the boom towards the center & concentrate on controlling the twist without the vang.


What I wrote previously in the thread about the vang concerned the situation when you don't have a traveler.

Johan
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samuel View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote samuel Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2012 at 16:35
Johan
I bet you would love to have another go in that Oppie for old times sake!!!!
Next year my granson will be old enough to start learning & my son has sorted a couple of Oppies out ro start in
I have already challenged him ( my son that is) to a race
This bought up a family debate about the time I nicked his & his sisters cadet & fell in
Ahhh!! Distant memories--- except they will not let me forget
Daydream Believer- Hanse 311- No GBR9917T- Bradwell Essex
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Johan Hackman View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Johan Hackman Quote  Post ReplyReply Direct Link To This Post Posted: 15 August 2012 at 18:26
Originally posted by Peter-Blake Peter-Blake wrote:

How much tension do you put on the backstay? Do you use the winch for it?

Originally posted by Swanji Swanji wrote:

... it looks as if you have tensioned the backstay by about a foot!


My back stay tackle has an extra loop which doubles the purchase compared to the original setup. If I count the blocks correctly the purchase is 32:1 instead of 16:1. There is no need for a winch to pull it as much as I did in the second set of pictures. It takes less force than to pull the main sheet in a strong wind.

I have been worried that the back stay is a bit too long and that I would not be able to bend the mast as much as required but if I study P-B's animation maybe I should not worry about it. A flatter main sail top than that might not be desirable. Let me know if anyone thinks differently.

Johan
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