jimi
Well-Known Member
Boat has a Cunningham but its not rigged, Is it worth doing so?
Cunningham
- Thread starter jimi
- Start date
lw395
Well-Known Member
Yes, if you want to put some effort into getting the best out of your sails upwind.
Being able to flatten the main properly can mean you can sail efficiently instead of having to reef. A good outhaul and kicker system helps too.
jimi
Well-Known Member
If I've got a fractional rig with adjustable backstay, does'nt tightening the backstay do the same job? Or is it different?
sailorman
Well-Known Member
they do similar jobs on the main
the cunningham will come into play when the main is hoisted up to the mast hd "black band", you then have the option to haul down with the cunningham to bring the sail max chord forward.
D
Deleted member 36384
Guest
The cunningham will pull the maximum depth of camber forward more than the Halyard can.
jimi
Well-Known Member
makes sense, thanks.
jubro
Active Member
A cunningham is a useful way to deal with inevitable halyard stretch. Racers will use it to tune the luff - there are various theories about moving the belly of the sail around, but the general principle is to flatten it for stronger winds and going upwind. If you've got older sails (like me) and a stretchy halyard (like me), the cunningham is a useful fix-it tool. With good sails and a non-stretchy halyard, its usefulness is a bit more esoteric. An adjustable backstay doesn't affect the luff tension. Depending on the rig tension elsewhere, the backstay can do one or more of the following things:
1. increase the forestay tension
2. twist off the top of the main by bending the top of the mast backwards
3. flatten off the middle of the main by bending the centre of the mast forwards
1. increase the forestay tension
2. twist off the top of the main by bending the top of the mast backwards
3. flatten off the middle of the main by bending the centre of the mast forwards
lw395
Well-Known Member
It's also much easier to adjust than the halyard, as the halyard is also loaded up by the leach tension.
You can adjust the cunningham with the sail set and pulling, to get the same luff tension from the halyard, you would probably need to slack the sheet and even lift the boom with the topping lift.
It works together with bending the mast, which flattens the front of the sail by taking up the luff round. Putting on some cunningham moves the remaing fullness forwards.
A cunningham needs to be a fairly powerful tackle, on my dinghies it is 16:1, but you you can pull much harder on yacht size rope. You don't have to pull it very far, and a powerful tackle also gives finer control.
jimi
Well-Known Member
I've got a wire halyard so there's no stretch on the halyard only what there is in the sail luff
Martin_J
Well-Known Member
Watch out.. Jimi will be going faaaaaaaast this summer... (when it arrives!)
alahol2
Well-Known Member
I used to have a cunningham. I used to use it as the 'first reef' by hooking it onto the reefing horn. I was always amazed at the amount of heeling power it took out of the rig.
wotayottie
Well-Known Member
I enjoy a bit of racing and even when cruising I play with all the sail controls on my boat. But my conclusion is that most of them are pointless unless a/ you are interested in the last tenth of a knot and b/ have good enough sails to take advantage of the controls.
For example on my decent quality 3 year old loose footed main, I cannot get the best sail shape that I want because the material has already stretched and my sail "hinges" at the top half and at the end of the battens.
As for the cunningham., are your sails nice new laminate jobbies? Do you have nice Dynema halyards so you can hoist the main and then use the cunningham to vary the halyard tension without it stretching too much? And what about the jibs because there is little point in messing with a cunningham on the main of a boat with a saggy old jib on a roller.
alahol2
Well-Known Member
I had that problem with the battens on my current main. Got the sailmaker to double the length of the battens and it now sets beautifully again.
Fire99
Well-Known Member
Does it have a Fonzie and and a Potsie too? 
William_H
Well-Known Member
It seems to me that the cunningham does a similar job to the main halyard in that it increases the luff tension albeit more easily. So if you have a decent low stretch halyard onto a powerful winch so that you can really stretch that luff then you won't do much better with a cunningham. But if your halyard has friction and stretch, a cunningham may do wonders for stronger wind up wind sailing.
Although as said the jib is far more important. good luck olewill
Although as said the jib is far more important. good luck olewill
SamSalter
Well-Known Member
The Cunningham does one thing - and one thing only - it moves max. draft depth fore and aft! ... and this moves as the wind strength changes.
As someone else pointed out, if there is friction in the luff, tightening the main halyard will tend to change the top end of the sail shape, but do little at the lower end. The Cunningham will do the whole lot.
It doesn't flatten sails or replace reefing. However, good sail shape and trim will delay the need to reef by reducing drag and increasing lift.
sam
As someone else pointed out, if there is friction in the luff, tightening the main halyard will tend to change the top end of the sail shape, but do little at the lower end. The Cunningham will do the whole lot.
It doesn't flatten sails or replace reefing. However, good sail shape and trim will delay the need to reef by reducing drag and increasing lift.
sam
sailorman
Well-Known Member
The Cunningham does one thing - and one thing only - it moves max. draft depth fore and aft! ... and this moves as the wind strength changes.
As someone else pointed out, if there is friction in the luff, tightening the main halyard will tend to change the top end of the sail shape, but do little at the lower end. The Cunningham will do the whole lot.
It doesn't flatten sails or replace reefing. However, good sail shape and trim will delay the need to reef by reducing drag and increasing lift.
sam
the cunningham only comes into use once the headboard has reached the black band.
it then tensions the luff downwards to alter the camber / draught of the main
Zen Zero
Well-Known Member
I wonder if a cunningham would tame my weather helm ...
Saggy old sails - they have more experience than the helmsman!
Why would the vang be important going upwind? To counteract flex in the boom?
How would you rig a cunningham to a previously uncunninghamed 28ft boat? A new cringle about a foot above the tack? Then what?
Thanks
Saggy old sails - they have more experience than the helmsman!
Why would the vang be important going upwind? To counteract flex in the boom?
How would you rig a cunningham to a previously uncunninghamed 28ft boat? A new cringle about a foot above the tack? Then what?
Thanks
lw395
Well-Known Member
I wonder if a cunningham would tame my weather helm ...
Saggy old sails - they have more experience than the helmsman!
Why would the vang be important going upwind? To counteract flex in the boom?
How would you rig a cunningham to a previously uncunninghamed 28ft boat? A new cringle about a foot above the tack? Then what?
Thanks
Yes, the cringle will need some reinforcement probably. A couple of layers of sailcloth perhaps?
Then add a decent purchase.
lw395
Well-Known Member
If you've got an old jib on a roller, then rolling more of it up and pulling the draft forward in the main with the cunningham works well on some boats.
It's cheap to try compared with buying a new jib.
It is very relevant to boats with stretchy halyards and dacron sails.
I used to race a dayboat with a bloke who was convinced the main halyard did the same job, because his main was slightly short on the luff and never quite made it to the black band. I rigged a cunningham, it was a big improvement, even compared to having a powerful tensioner on the halyard.
Unless the sail is totally loose footed, halyard tension is absolutely not quite the same thing. Even a shelf foot/lens foot spreads force into the body of the sail.
Even in a loose footed sail, the cunningham or downhaul is way easier to adjust on the fly, because you have much less friction and are not fighting the leach tension.
