why order a new sail with a cunningham ?

[simonfraser]

on my old dacron main i pull the tack down with a winch to tighten up the luff as needed. this works well.
when i order a new laminate sail, shall i do the same, or order a cunningham as an extra ? if so, why ?

 

[Alfie168]

I'd have a chat with the sailmakers personally. I suppose it depends on whether the power of a winch might overstress a laminate if the 'pull' were against its construction bias, but I may well be talking 'ollocks here.

I dunno is the short answer...

Tim

 

[VicS]

[ QUOTE ]
but I may well be talking 'ollocks here.

[/ QUOTE ] sail makers do caution against overuse of the cunningham with laminated sails.

 

[William_H]

A cunningham to my mind is redundant if you can get a lot of effective stretch of the luff with the halyard winch.

If you have a tack where you can pull it down with a winch again cunningham becomes redundant.

However if you can't get enough tension on the luff with the halyard and the tack is fixed then a cunningham is ideal to get a bit more stretch in the luff.

A cunningham and a coresponding flattening reef clew eyelet can flatten a sail beautifully by folding up the bottom 2 or 3% of the sail which includes the very full bottom. If you don't want to stretch the laminated sail so much you can release the halyard by the same amount.

So it is all up to you what you want. I would have one though for the small extra cost. olewill

 

[simonfraser]

tnx olewill, that's what i'm thinking too. it's much easier to create extra tension by pulling down, rather than up. uhuh wot diid i just say . . . .

& vics point about laminated sails is interesting too.

 

[bedouin]

If you are not racing then I can't see any benefit of using a cunningham over the halyard or tack downhaul.

They are of some benefit when racing because they enable you to tighten the luff without lengthening it

 

[reeac]

[ QUOTE ]
If you are not racing then I can't see any benefit of using a cunningham over the halyard or tack downhaul.

They are of some benefit when racing because they enable you to tighten the luff without lengthening it

[/ QUOTE ]

I've always assumed that the point of the Cunningham was that it applied vertical tension at the tack regardless of any mast-track friction along the leach which would limit the effects of halliard tension. Have I got that right?

 

[kds]

"regardless of any mast-track friction along the leach "

Along the luff ?
And yes - you are right.
Ken

 

[savageseadog]

It's a bit of fine tuning which enables the main to be flattened a bit more while the mainsheet and kicker are full on. OK for racing but not necessary for cruising.

 

[bedouin]

I'm not sure that it's as much about friction (which works in both cases) but more that the cunningham tends to have more purchase than a halyard. My main halyard does not have a winch so the sail is hauled up manually and then tensioned with a 3:1 tackle on the downhaul (and if I were racing that would be 4:1 or even 6:1

If you have a winch for the main halyard I don't see any need for a cunningham for cruising.

 

[reeac]

[ QUOTE ]

"regardless of any mast-track friction along the leach "

Along the luff ?
And yes - you are right.
Ken

[/ QUOTE ]

Oops!, yes I intended to say the luff.

 

[afp]

RedBoat's a 40ft ex racer converted for fast cruising. She has a cunningham on a 6:1 tackle.

To tighten the luff with the halyard is quite a struggle because of the friction (15m luff) and the mainsheet needs to be freed off. Using the cunningham is easy, no winching required, and as soon as you come off the wind the tension can be released simply by pulling the line out of the jammer.

(We also have a leech line which runs up the sail, over a small block on the head board and down the luff to a jammer on the boom - very useful when you can't reach the end of the boom.)