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Rigging a Cunningham

Gary G

Member II
I have a 1983 E28+ that has no Cunningham. I would like to rig one and have seen what looks like some pretty good examples on the Harken web site. Any suggestions on what works well? One concern is using a Cunningham hook vs just threading a line through the Cunningham grommet in the sail. Thanks in advance for any input.
 

rssailor

Moderator
Cunningham

Don't bother, cunningham makes little difference in sail trim. Have never rigged one on my 25+ and rarely use the one rigged on either of my Coronado 15's that get raced a lot. A good boom vang with lots of purchase, an outhaul that can flatten the foot of the sail and having a good powerful purchase on the backstay to bend the mast are much better ways to depower your main in heavy air. Ryan Ericson 25+ Moonglow :egrin:
 

Seth

Sustaining Partner
Cunningham

In a brand new mainsail, it is true that as long as it is exactly the right luff length, you will rarely need the cunningham.

But especially on older dacron mains that are basically full luff length sails, the draft has often been "blown back" in the sail, and when the breeze is up this is the best way to help pull the sail back into shape-I would definitely have one set up if I were doing any racing, or even if I just wanted to keep my sail performing as well as it can-even if it is used only occasionally.

How to rig is a bit loaded-depends on whether you want it led to the pit or not, but bascially, you need at LEAST 4:1 purchase, and I am a fan of tying off one end of a very low stretch cunn. line somewhere on the gooseneck and running the line through the cunn. grommet, and then attaching THAT end to whatever purchase you rig-this is a clean set up and gives you another 2:1 purchase right off the bat-or if you have a decent 3:1 block and tackle and use this as well, you end up with a nice 6:1 system. The only advantage I see in using a cunningham hook (attachced to the grommet) is if your reefing system requires you to use the cunningham for the tack reef (lower the halyard to a pre-marked point, then, having already put the cunn hook in the reef tack, you just wail on the cunningham to get the right luff tension).

So, this is a pretty personal thing to set up, but just make sure you have enough purchase!

Cheers
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
"Is the Mainsail open? I feel a Draft!"

Seth has, again, explained it very well. :hail:

I also use the cunningham when the wind pressure goes up, for the reason stated. I view it as part of the sail shape control, along with the outhaul.

(On our last boat, a Niagara 26, with it's tall fractional rig, the backstay was the third mainsail shaper, FWIW.)

Best,
Loren in PDX
Olson 34 #8

ps: see you all in Port Townsend!
:egrin:
 

Seth

Sustaining Partner
I'm not worthy

Loren, it is I who am not worthy to be among this group ;) ;) :p !
Certainly not one to argue with Loren, I need to at least put these 2-3 pennies into this taalk:

Provided your sail is in decent shape, and the backstay is easily adjustable, it is probably THE most effective way to power and depower the sail when it needs to be done quickly (as in puffy conditions).

Outhaul and cunnigham are all good ways to more or less "set" the draft location and draft amount for a given leg of the course, but if you are sailing in puffy conditions, the bs is MUCH more effective (oh, yeah, the rig must have some bend ability-but the 32-200, 34, 35 and 38's certainly do).
Why? Nothing affects depth or "power" as much as luff curve in the mainsail.

Adding or removing even 3" of bend (which adds or removes a corresponding amount of luff curve) will usually take 50-70% of that depth in or out of the sail.

If you have a good main trimmer, and someone sitting behind the driver with a good self-contained bs adjuster (or on smaller frac boats a fast block and tackle), you can make HUGE gains against a similar boat sailing along side in these conditions.

Anyway...Just happy to be here! :egrin:

These are my first icons!!
 

tilwinter

Member III
backstay adjuster

Seth:

First let me say how much I have appreciated your posts on so many various subjects. :cheers:

The subject of sail shape is endlessly interesting, but if one can only get out a few times a year, it is hard to remember from one sail to the other, what one should be doing. :eek:

My e30+ is fractionally rigged, and I have been trying to figure an inexpensive and inobtrusive way to rig a backstay adjuster since I bought the boat 3 years ago. The task is hindered by the fact that the bimini would need to be modified to accept the hardware between the split backstays.

I gather from this most recent post that you would highly recommend adding the bs adjuster, even if it is relatively expensive and clutters up the area behind the wheel.
 

Seth

Sustaining Partner
30+ Bs

;) Anyway-yes, it is an endless discussion.
Actually the 30+ is a great candidate for a simple system because of the split backstay. A pair of wire blocks designed to pull both halves of the backstay together connected to a 10:1 or better purchase is relatively easy to install and not too pricey...I think the Haken catalog has examples of this setup, and if you find one that looks good, feel free to run it by me-or, maybe some of the 30+/28+/25+ owners can send some pics..
As much as I like using them, you must ask yourself if you are doing the kind of sailing where you will benefit from the ability to quickly change sail shape.

If you strictly cruise, it may not be worth it. If you race at all, I think it is. I know some 30+ owners who have a couple of turnbuckle settings:eased off on light days, and tighter in 2" incrememts-so as you get ready to leave the dock you can tune as needed.

Only you can say if this is for you, but it does help optimize performance!!

S
 

diamondjim

Member II
Hi Seth, Loran and others,
This discussion is exactly what I've been waiting for! BS adjusters, sail shape, cunninghams etc. Ok, topping lifts w/vangs change sail shape because of mast bending. BS adjusters will bend the mast as well and move the center of effort for & aft therefore changing helm pressure - but not sail shape (?). Do I have this correct?
During a shake down cruise last Friday, I tightened the BS one full turn bringing the mast aft. The boat seemed to steer very well in the heavy air that day and we made good speed. Full main and partially reefed head sail.
I guess what I am saying is that there seems to be a balance between all these adjustments and knowing when and how to make them.
The other question is how tight is "tight" on the cunningham or outhaul?
Thanks!!
<> Jim
 

Seth

Sustaining Partner
Glad you like it

Well hello there, Jim!

Actually there has been a pretty consistent thread on this and related topics for the last few years-with many of the key points repeated in several different threads...But no matter.

I'm glad you are enjoying this, but I fear you may be a bit confused (and this is one which I spent a LOT of time explaining previously) on the bend vs. rake discussion.

Also I have no idea what you are referring to when you said "topping lifts with vangs change sail shape because of mast bend"??? Please let me know on that one!

Mast bend will change sail shape, and the vang will also-in a different way. The topping lift is used on boats without 2-way vangs to open the leech in light air (mostly cruisers).

Please look back for a very detailed post I gave on this topic, but I will briefly run through it for you here:

RAKE, which is the "at rest" fore and aft location of the masthead, changes the center of effort relative to the Center of gravity in the keel, and hence the "feel" of the "helm". Moving the masthead back will move the CE BEHIND the CG, and INCREASE weather helm. The by product is higher pointing, or better upwind performance at the expense of downwind speed. In light air (especially for racing) you want aft rake to help your upwind performance. In heavy air, ideally you would want less rake to reduce what may have become excessive weather helm. Certainly if you going to be adjusting rake, you would want LESS in heavy air-not more. Cruising boats rarely adjust the rake once they find a good spot-but MANY cruising boats DO bend and unbend their masts-it is easier and more practical. RAKE is changed by using BOTH the headstay and backstay to move the top of the rig. Just changing one of these will not really affect the rake. In the 70's, many race boats used hydraulics to both bend the mast AND change the rake when sailing. This was ultimately found to be 'too effective" and the rules now allow only one (headstay or backstay) to be adjusted while racing. The idea is to allow mast bending, but not raking. Rake may always be adjusted before or between races.

One you have the RAKE set with given lengths for the HS and BS, most boats that have adjusters will use a BS adjuster, which will do 2 primary things: Tighten (or loosen) the headstay, and bend/unbend the mast. Obviously they are done in concert with each other. Add BS tension, and the HS gets tighter (which flattens the jib), and bends the mast back (which flattens the main). Get the idea? Big wind requires flatter sails, and adding BS tension does this for both sails. When the breeze lightens up, easing the BS will "power up" the main by "unbending" the mast, and "power" up the Jib by alllowing the HS to sag off more-which is very fast in light air. The mechanics of why the main gets flatter when the mast is BENT (not raked) aft is discussed in more detial in old posts-The reason you are bending and not raking in this scenario is that the headstay is not changing its' fixed length-only the BS-Got it?

Great outhaul question!! I love this one. When the boat is consistently heeled more than about 15 degrees, you need the flattest sails you can get-that means "maxing" out the outhaul to get the lower 1/3 of the sail as flat as possible. When the wind gets light and the boat feels "starved" for power, I will usually ease the outhaul 2-3", or put differently, go for a max. of about 3" of "depth" or amount of sail that settles to leeward just above the boom.The exact amount varies from sail to sail, of course. Be carfeul of the "old salts" who say "Bag it out"-a "fat" sail WILL accelerate from a stop better than a flat one, but it has a built-in top speed limit because of the drag due the "fatness" of the "wing" section or profile.

When sailing downwind, these same guys may ease the outhaul 8-10" sometimes-thinking it is fast, but remember that downwind is the least efficient point of sail and the only time that the only driving force you have is projected area (as opposed the lift), so if you ease the outhaul a lot you reduce the distance from the tack to the clew, and hence projected area. In fact, easing the outhaul too much is the same as REEFING!!

The cuningham/downhaul has been discussed. Only use it IF: the sail is ALL the way up, and the draft is visibly aft of the 50% mark (fore and aft). If the sail is well stretched out, and if you have excessive wrinkles in heavier air, you can use it gently to remoive the wrinkles-but this is NOT the prime function of a cunningham or halyard, for that matter-they are used for keeping the max. draft in the best location. Luff wrinkles in light air are fine-again as long as the draft is forward of the middle of the sail.

Really kept it short, huh? :oops: :eek: :eek:
 

windjunkee

Member III
Seth is a golden god !

ok, I'm pitching in too. We are playing with the rig right now. We are buying a backstay tensioner for our 32-2, with a mast that really won't bend. (we can, however, affect mast rake and headstay tension)
I believe we're going to go with a Navtec hydraulic system, with a shorter piston length. We don't want too much pressure on the backstay because of the deckstepped mast. We are concerned, however, with the necessity of putting in a compression post in the cabin and whether we need to step the compression post to the keel or just to the cabin sole. We need the post to be removable because the area of support is right in the doorway to the head and forward cabin.

On the Cunningham issue, we have a gooseneck that slides on a track probably 2' long. We do not have a cunningham cringle on the main, but we installed a 4:1 block/tackle system to pull the boom down on the track, thus tensioning the luff. Seems to work great.

Jim McCone
Voice of Reason E-32-2 Hull #134
 

Seth

Sustaining Partner
Smart

Jim,

If you plan to race as much as you have indicated, it is a GREAT idea to come up with a "sister" for the compression post-especially a removeable one-this is a great, great idea to maximize performance and strength!

The Navtec is fine-just remember RAKE will not change unless you adjust BOTH the HS (obviously by turnbuckle) and BS. In, fact, here is the hot tip for you:

Set the ideal rake for the boat going upwind in light air with the hydraulic adjuster almost all the way eased-using the TURNBUCKLES on both HS and BS. With the rake now set, you can use the hydraulics to reduce headstay sag when the breeze comes up, or increase it for better pointing in light air, while at the same time you can probably get 2-3" of bend in your mast if you keep the aft lowers loose (this will also let you ease the main more when sailing downwind), to FLATTEN the main to some degree.

OK, you now have a good rake set up. On very heavy days, shorten the Headstay before going out with the turnbuckle. This will remove some RAKE (for a given amount of BS tension), and thus helm in big air.

And..you have good rake for up wind sailing, but not so much for downwind, right?

When you go downhill, ease the BS adjuster ALL the way off. You will notice the HS is flopping around some (or you should). Now, take the Jib halyard down to the stem fitting and WAIL on it making the HS even looser. You have now pulled the masthead forward-reducing aft rake and making the boat noticeably faster downwind!!!!

Good job with your floating gooseneck!

Cheers
 
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mark reed

Member III
We need you in Port Townsend, Seth!

Seth,
Sure wish you could come to the NW Ericson Rendezvous this weekend and help me learn to get better performance from my rig. I really appreciate all the information you have posted on sail trim and other topics.

I'm sure we'll all raise our glasses to toast you this weekend!
 

Seth

Sustaining Partner
Thanks very much

I really appreciate the sentiment-and wish I could join you-sounds like :egrin: !

Anytime you or anyone else has a specific question that might be redundant for the forum you can always contact me directly. This way if it has been covered but you are are still not sure about it or there is something unique to you we can get it sorted out without repeating things here...

Have a ball!

S
 

Roger Ware

Member III
Rigging a Cunningham - reprise

Hi - posted a new thread on this same topic and then found this old one, so I posting my question on the old one too (is there a way to cross reference threads?)

Just wondering - why do big boats put a Cunningham Eye in their mainsails? Surely you can achieve the same effect by just tensioning and easing the halyard (cant usually do that on a dinghy because it is cleated off and no winches).

Cheers, Roger
Kingston, ON
Starlight II
E38 200
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Why the Eye

Hi Roger,
Long story / but will try to keep short..
:)
Long long ago (well, in the sixties anyway) it was common for sail boats to have a sliding gooseneck. Having already pulled up the main halyard as tight as possible... when wind speed went up you put more tension on the luff by pulling down on the gooseneck with another line.

For racing, there needed to be a method to keep main sails inside a predetermined triangle for controlling total potential area. Left to their own greedy devices, some skippers would have sails that pulled down lower and lower, and, well... lower. First the measured Black Bands were painted/taped on the mast to denote the lower limit of the sail. Next, most production builders went to a fixed gooseneck to control costs and standardize sail building. Also, since most of their boats were really intending for a non-racing market, they knew that booms that hit family members on the head while sitting down were bad for reputations.
:rolleyes:
Note that you still see the designer-designated black bands on the back of the boom and at the top part of the mast, too. Same reason.

In sail boat racing, at least below the higher-tech levels, adding sail area for boats has always been kind of akin to the old sports car racing axiom that "there's no substitute for cubic inches."
Personal prejudice: no matter how much I like the sound of a howling hi-tek F-1 small block... I still prefer the sound of a big block V-8 thundering down the straight! Ya feel it ...and... hear it. :D

Whether you race One Design, or in some sort of pre-measured handicap system, everyone needs to know that your "maximum sail power" is openly accounted for before the start.

So, with the boom gooseneck limited by the black band AND nowadays fastened in place, you pull the draft forward by putting downward tension on the luff of the sail with the Cunningham line (often a multi part tackle).

Of course, when Seth checks in and tells it better, I will have to change all the wrong parts of this message!
:devil:

Cheers,
Loren in PDX
 

Roger Ware

Member III
ok I think I get it now ......

Loren - right, OK - I have raced plenty of (small) boats with sliding goosenecks, but, what you are saying is - mainsail pulled to both black bands, how do you get more luff tension without infringing? Answer: with the Cunningham. Do I pass?

Thanks, I can go puzzle about something else now.

Cheers, Roger.
 

Seth

Sustaining Partner
Nothing to add to perfection

Loren has it-cunninghams are found on Lasers, 420's, Lido 14's, Rhodes 19's, Ericson 30's, etc. The existence or lack of same on mainsails is not related to size, but the boat and/or its' intended purpose, and to some degree the fabric used for the sail.

The rest has been covered, methinks!

S
 

SeaRogue

Member II
What hardware for a cunningham/reef line?

I am reviving this thread to avoid duplication of information relating to cunningham rigging.

My boat does not have a cunningham and I am considering rigging one. I read in this thread that the cunningham can do double duty as the forward most reef line. I also want to add reefing lines to my boat.

My manual indicates that the hardware specified for the cunningham from the factory are schafer parts. Sch. 05-43 and Sch. 22-59. I cannot find parts with those numbers. It appears that the part numbers have changed since my boat was built in 1985.

Does anyone know:

1. What the part numbers are for the parts that I would use today?
2. Is any modification necessary to use the cunningham as a reef line?

In addition, I would appreciate any information about how to rig the aft reef line.

Thanks
 

bayhoss

Member III
Question for Seth

In reading your posting on the bs adjusters I first want to say thank you to you and Loren for a wealth of information. I understand the benifits of bending the mast aft to tighten the jib luff and improve the main. My question is if the boat has a roller furler on the jib, does bending aft still give the benifit of tension to the luff of the jib. And, if not, what adjustments need to be made to the main?

Best,
Frank
 

Seth

Sustaining Partner
Rf

The presence or lack thereof is invisible to your backstay adjuster, so you will use it the same way whether you have a furler or not.

In light air, keep it as loose as possible to make the HS sag as much as possible, which will make the entry rounder and easier to steer to and make the genoa as full as it can be, which will create the maximum amount of power. The loose BS will also keep the mast straight, which will keep the main as full as possible. In light air, start with it completely loose, and watch the HS as you sail through the little waves. Add ONLY enough to steady the HS from moving around as you hit the waves, and no more. As the breeze comes up, the HS will begin to sag TOO much, the boat will heel excessively and you will have reached the point where adding a bit more BS will begin to reduce some of the (now) excess deoth and sag in the headsail. This is also the time when you will want a slightly flatter main, and as you know, more BS tension will correct this at the same time.

Just play around until you have approximate BS settings for 0-5 ish, 6-10 ish, 11-16 ish, and 17+ ish wind speeds.

Cheers
 
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