Cunningham

[spiller]

That extra eye in the sail, above the boom, did mystify me somewhat, but I assigned it to be somewhere to hang a coathanger and dry wet gear!

However, saw a thread here that referred to Cunn...m and investigated.

Just how does one rig it or is it simply a loop of rope that can be shortened to trim the sail?

All advice on the subject welcomed!!

 

[bbg]

Typical arrangement is to have a metal hook on a strop, with the strop attached to a purchase that is attached to the base of the mast.

Hook goes through cunningham cringle. Strop should be long enough so that it reaches below the boom, even when cunningham is completely slack.

When you want to tension the luff of the main, (i.e. flatten the main), pull in on the tail of the purchase. It can either be made off at the mast (i.e. on a cam cleat that is an integral part of the lower block) or led back to the cockpit.

 

[bedouin]

I think it is unlikely that you will need to use the cunningham unless you are racing. You can achieve pretty much the same result with the main halyard.

 

[Jonny_H]

Well, that depends on your sail really. If you can hoist your mainsail to the very top of the mast on the halyard, then you need a cunningham to take the bag out of the front of the sail when the wind picks up. If however your mainsail is bar tight with the head 6 inches or so off the top of the mast, then I agree, you can get a simalar results using the main halyard to tension the mainsail.

The two will give different results - the halyard pulls the sail up, hence putting less tension on the leach (therefore you need to adjust the kicker to suit), the cunningham pulls the sail down which will close the top of the leach.

Ultimately when racing you use it a lot when its windy. If cruising - I wouldn't use it except when your at the marginal stage between full main and reef 1, when it could be useful to depower the main slightly.

Jonny

 

[Salty John]

A conventional cunningham uses a line secured at one side of the bow, up through the cunningham hole, down to a snatch block secured ahead of the tack point, then back to a winch or cleat at some convenient point.
A cunnigham hook is also available so you can hook directly into the cunningham hole, and then lead as above.
If the wind is variable you can adjust the jib shape without adjusting the sheet. On the wind, as wind speed increases and the draft moves back you tighten the cunningham to bring the draft forward again.
I've always thought of the cunningham as a racers tweaking device of little value to cruisers, but I'm sure others will disagree. An advantage to racers is that they can adjust the luff tension on a fully hoisted jib where increasing halyard tension would take the sail beyond the band. Also, increasing luff tension from the bottom means you don't have to adjust the genoa sheet cars as you would with halyard tension which causes the draft to move forward.

 

[Salty John]

Oops. Just realised you are talking about your main, not a jib cunnigham as I have described!
Must pay attention!

 

[Jonny_H]

Exactly the same principle applies though ....

 

[bedouin]

Well if you have to pull your main right to the top of the mast and the luff is still too loose then I would suggest that the sail is too big /forums/images/graemlins/smile.gif

However when racing you don't want to hoist past the black bands so having a cunningham in effect enables you to have a larger sail for light weather while still being able to get sufficient luff tension in heavier winds without breaking the rules.

As you suggest there is nothing you can do with the cunningham that you can't do with the other conventional controls - so it just becomes a matter of convenience / . The specific advantage of a cunningham is that it tends to be just one pull on a rope, whereas to do the same with the halyard could involve letting off the kicker and main sheet, then tightening the halyard and then reseting the kicker/sheet.

 

[Phoenix of Hamble]

Also, on many cruising boats (note - not all!), the luff isn't completely free in the track (especially those with bolt ropes and plastic slugs), so the halyard doesn't always tension the sail properly, or indeed, without going head to wind, can often not be further tensioned anyway.... whereas a cunningham usually can...

IMHO, too much hassle for a cruiser mind you.....

 

[vyv_cox]

I read an article many years ago advising that a Cunningham can be quite useful on a cruiser. Over years the main luff tabling (or bolt rope) will normally reduce in length relative to the sail, actually I suppose the sail cloth stretches more than the luff. Using a cunningham will take out the bagginess that is a natural development in an older sail.

In the case of a masthead rig with an overlapping genoa it's academic anyway, as the very slight improvement that may result from usin the cunningham is imperceptible in terms of boat speed or pointing. It just makes the main look a little better.

 

[charles_reed]

I think he's referring to the main Saltyjohn

 

[flaming]

Due to the friction of the luff on the mast the Halyard and the Cunningham flatten very different parts of the sail. Adding tension to the Halyard will flatten the top part of the sail, but the belly of the sail, where most of the power is, will be largely unaffected. The cunningham will flatten the bottom of the sail.

 

[Lakesailor]

I had all these problems. Tight sliders, headboard at the top of the mast and a rather fuller luff low down in the sail than I would have liked. Do you spend money having the sail and sliders altered, or spend sod all making a cheap remedy?
I rigged a simple (cheap) cunningham using a kicking strap from a dinghy and a carbine hook. In this piccy it has the yellow and blue line. I ran it either side of the gooseneck as it started at the bottom block, up to the top and back down to the bottom. It worked well as I had roller reefing, which I never even tried using. It was only an 18ft boat so the lightweight gear sufficed. It was about 18 knots of wind in this piccy.
(Yes, I know my headsail halyard is laying across the cabin roof, but I can only do so many things at once /forums/images/graemlins/grin.gif)

 

[charles_reed]

Despite what some say the Cunningham can be a very useful addition to the cruising sailors' tackle.
It does depend on the the rig as to how much value it is and unless it's permanently rigged it won't get used,

Low value for headsail rigs with small mains, highly valuable for boat's relying on a big main.
Not advisable for in-mast roller-reef.

Invaluable for "stretchy" halyards and older mainsails.

My single-line 1st reef now doubles as the Cunningham (the amount you slacken the vang controls the balance of luff/leech tension) and it's used about 50% of the time I'm going to windward.

Before I had the single line reef I used both a flattening reef as well as a Cunningham, though the former became redundant with a fully-battened main.

 

[lw395]

A cunningham is easier to adjust than the halyard, becuase the halyard is loaded up by the leach tension. Its worth having on any boat imho, its nice to try getting the best from the sails. Many sails now are cut with the assumption that a cunningham will be used.
A 4:1 tackle with a jamming block of some sort is a good start.
Make sure its easy to free right off to hoist the main.
Hope that helps.

 

[Inselaffe]

Best thing I ever did... /forums/images/graemlins/smile.gif

My rather tired main is completely flattened off by the simple Cunningham I rigged up, meaning better upwind performance, delayed reefing, and delayed having to buy a new main!

I just have a rope tied to the gooseneck which goes up through the cunningham eye, then down to a 3:1? tackle, the tail of which is led through a block at the mast foot back to the cockpit.

It flattens the sail off much much more that the halyard manages (I guess because of friction in the plastic slugs?)

I never understand this 'not needed for cruising' thing, but then again I do come from dinghies, am a bit of a what the Germans call a 'string puller' and it puts a real hurt on my eyes to see a sail not set as it should be /forums/images/graemlins/smile.gif

 

[William_H]

Yes a cunningham system is good for flattening the sail.
However a good winch to haul up a main sail which doesn't have too much friction or stretch in halyard will do the same job.

Also good to match a cunningham is a flattening reef ie an eyelet on the leach which can have an outhaul attached to pull down the leach to a similar amount to the cunninngham.

Sails must be flat in strong wind. olewill

 

[Alfie168]

I've always had a cunningham on the basis that you can never have too many bits of string to pull on a boat. If you think its improved the sail shape and depowered the rig, then it almost certainly has.

Seriously though, on an Enterprise dinghy with such an oversized mainsail relative to boat length, a cunningham was an essential piece of kit to depower. I can see its use on a cruiser, but its not quite so essential, but still useful to have.

Tim

 

[spiller]

Thanks for all the advice. I will enjoy making up the tackle and experimenting.

On a similar subject, see new post "Setting Genoa"