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Catalina/Capri 25/250 Sailor's Forums

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Mainsail cunningham vs. boom downhaul

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n5lfy
Deckhand

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USA
15 Posts

Initially Posted - 05/09/2002 : 11:23:28

Just got a new mainsail with a cunningham. On a boat with a boom gooseneck that is fixed to the mast (like an S2) I can see the need for the cunningham. But the Catalina 25 boom is free to move up and down the mast slot allowing the use of a downhaul to tighten the luff on the mainsail. Why would one choose the use of a cunningham, which seems to me would leave the foot with extra draft, as opposed to a downhaul? The only answer I can guess, is if the mainsail is blown out and tightening the downhaul would cause the boom to be below the class limits then a cunningham would allow additional luff control.

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Douglas
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Response Posted - 05/09/2002 : 12:48:35

Im confused here. I was under the impretion that a down haul was used to aid in droping a sail or to pull it down. The cuningham was attached to the boom at the lower forward area and was used to pull down on the boom and resultant effect pull the leading edge of the sail tight. If you are refering to a gromet in the sail it might be part of a reefing system.

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Champipple
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Response Posted - 05/09/2002 : 13:30:52

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
Im confused here. I was under the impretion that a down haul was used to aid in droping a sail or to pull it down. The cuningham was attached to the boom at the lower forward area and was used to pull down on the boom and resultant effect pull the leading edge of the sail tight. If you are refering to a gromet in the sail it might be part of a reefing system.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Downhaul has many uses (definitions) on a boat, as does topping lift. A downhaul, on the boom holds it down (keeps the boom from rising, similar to a vang) but at 90 degrees to the deck at the mast) There is also a downhaul on a lot of racing genoas that aid in pulling the sail down/across when tacking. Or a downhaul on a spin pole, which keeps it from bouncing up.

I do exactly as n5lfy is talking about in most instances, that is, attach my cunningham to the boom and use it as a downhaul. However, there are times, Lighter winds, where lowering the boom in this manner isn't enough make the sailshape correction I want and I need to put the hook in my main and not in the boom..

DW

Duane Wolff
"The Flying Wasp"
C-25, #401 std,sk
Chief Measurer C-25/250 national Org.
<img src="http://im1.shutterfly.com/procserv/47b2dc20b3127cce9cd2f45b211a0000004010" border=0>

Edited by - Duane Wolff on 05/09/2002 13:33:08

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Steve Milby
Past Commodore

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Response Posted - 05/09/2002 : 14:48:53

A “dousing line” is a line that is used to douse, or bring down, a jib.

A “downhaul” is a line that pulls down on a spar or the tack of a sail to tighten its luff.

A “cunningham” is a line that is used to control tension along the luff of a sail.

Downhaul
On a C-25, a mast slide is attached to the gooseneck. The mast slide has a hole in the bottom of it. The downhaul consists of a short piece of line that is fed through the hole in the bottom of the mast slide. There is also a black jam cleat in the mast slide, below the gooseneck. After you raise the mainsail, you wrap the bitter end of the short piece of line around the black cleat, pull on it (to put tension on the luff of the mainsail), and then you tie the line off at the cleat.

Cunningham
On a C-25, the cunningham consists of a pad eye that is attached to the portside of the mast, about halfway between the boom and the deck. A piece of line is run through that pad eye, and then through the cunningham grommet that goes through the mainsail, about a foot and a half above the boom. Then the bitter end of that line is run down through a hole in the base of a cleat that is situated on the starboard side of the mast, about halfway between the boom and the deck.

Both the downhaul and the cunningham are used to adjust the tension of the luff of the mainsail, so they both accomplish the same general purpose, but the tension of the downhaul should ordinarily be adjusted loosely, for sailing off the wind. When you want to beat to windward, you pull down on the cunningham to increase tension on the luff, thereby flattening the sail and moving the pocket forward. When you change course and sail off the wind again, you simply release the tension on the cunningham, and the luff of the mainsail will be properly tensioned by the downhaul for sailing off the wind.

If you don’t want to use the cunningham, or if you don't have one, you can increase the tension on the downhaul when you want to beat to windward, and release the tension on the downhaul when you sail off the wind, but it is probably a little quicker and more convenient to use the cunningham, especially in stronger winds.

The cunningham is also used in conjunction with the factory stock jiffy reefing system, to draw the reefing grommets down to the boom.

Steve Milby "Captiva Wind" C-25 T/FK #2554

Edited by - Steve Milby on 05/09/2002 17:42:52

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joshuaheard
Deckhand

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USA
22 Posts

Response Posted - 05/09/2002 : 16:45:37

I've read that the downhaul is tightened to tighten the main leech, as when it flaps. The cunningham is used to tighten the main luff. This is usually done when going upwind to make the sail flatter.

I think the original poster has a good idea, in fact, I was just wondering what that hole was for on the gooseneck track slide, because my mainsail also has a cunningham grommet. I think that the gooseneck can be used with a cunningham to tighten the luff *to a certain extent* (ie reaching upwind). However, to *really* tighten the luff (ie close haul in high wind), use the sail grommet.

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dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
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Response Posted - 05/09/2002 : 17:36:04

I have read that the cunningham should be fastened to a cleat on the mast, not the boom, to keep the load off the gooseneck. I think some time ago in another topic, someone said their cast gooseneck broke with almost catastrophic results. What do you think?

Don Lucier, Northstar
C25 SR/FK

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Derek Crawford
Master Marine Consultant

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Response Posted - 05/09/2002 : 18:22:31

On "This Side Up" I don't use a downhaul on the gooseneck. I do have a 3-1 purchase on the Cunningham which comes back to the cockpit. To tighten the luff of the main we haul on the halyard and then tension the Cunningham. When going off the wind we ease the main halyard and throw off the Cunningham.We almost never have a problem with the gooseneck rising up.
Incidentally, I don't have any of those cleats or padeyes that Steve describes - they weren't on the boat when I bought her.
Derek

Edited by - on

eric.werkowitz
Captain

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Response Posted - 05/09/2002 : 18:37:27

In a thread a year or two back, this topic was covered. The best explanation I heard for the seeming redundancy between the downhaul and the cunningham was for racing. The poster offered that using the downhaul during single design racing resulted in a larger mainsail due to the stretching. Therefore, by using the cunningham, the luff could be tightened without the sail increasing in overall dimensions.

Eric Werkowitz
C25 #4969

Edited by - eric.werkowitz on 05/10/2002 09:54:22

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Steve Milby
Past Commodore

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Response Posted - 05/10/2002 : 01:06:21

Eric,

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>The best explanation I heard for the seeming redundancy between the downhaul and the cunningham was for racing. The poster offered that using the downhaul during single design racing resulted in a larger mainsail due to the stretching. Therefore, by using the cunningham, the leach could be tightened without the sail increasing in overall dimensions. <hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

The downhaul and cunningham aren't really redundant. Logic tells us that there wouldn't be so many boats equipped with both devices if they were really redundant. The downhaul is used to put tension on the luff of the mainsail when sailing off the wind, and the cunningham is used to apply tension when beating to windward. Also, the cunningham is used as a part of the jiffy reefing system. The downhaul is not.

Also, the explanation that was offered by the previous poster is not supported by the racing rules. According to the poster's theory, if the mainsail is bent onto the boat, and if the downhaul stretches the sail beyond the maximum dimensions allowed by the racing rules, then the sail would be disallowed. The C-25 Design Class Racing Rules require that sails be measured off the boat, on a flat surface. If the sail conforms to the size limitations when measured on a flat surface, it can be used in the national regatta, no matter how much it may stretch after it is bent onto the boat. The rules do not provide for measuring the sail after it is bent onto the boat.

Derek,

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote> On "This Side Up" I don't use a downhaul on the gooseneck. <hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

If you don't use a downhaul, then the only thing holding the luff of the mainsail down when sailing downwind is the weight of the boom. That is sufficient when sailing downwind in very light air, but when even a moderate wind is blowing, the luff of the mainsail will pucker, and the surface area of the sail will, in effect, shrivel in size. (And we all know that size counts, especially when we're talking about sails.) So, Derek, if you don't want your sail to shrivel and pucker, you'd better rig a downhaul.

Duane,

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote> I do exactly as n5lfy is talking about in most instances, that is, attach my cunningham to the boom and use it as a downhaul. However, there are times, Lighter winds, where lowering the boom in this manner isn't enough make the sailshape correction I want and I need to put the hook in my main and not in the boom.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

You are using one device to serve two purposes, which is functional, but if you have a separate downhaul and cunningham, then you won't have to detach the hook from one place and attach it elsewhere, which saves you some motion. More importantly, however, if you have a separate downhaul, you only have to adjust it once, when you raise your mainsail. Thereafter, you either apply or release the tension on the cunningham, depending on whether or not you are sailing to windward, but you don't have to readjust the downhaul.

The way you are doing it now, whenever you release the cunningham, you have to hook it up to the downhaul and adjust the tension on the downhaul. What you are doing works, but if you have both devices, it will be easier and more functional.

Steve Milby "Captiva Wind" C-25 T/FK #2554

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Greg Jackson
1st Mate

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Response Posted - 05/10/2002 : 09:09:12

The cunningham is, without a doubt, a racing control. There are not two, but three controls which do the same thing to the luff length:
main downhaul (if gooseneck isn't fixed)
cunningham
main halyard

Of the three, the cunningham is the only one which increases tension without increasing overall sail size. In a race the mast should be marked with black stripes to indicate maximium lift of the head, tack position, and maximum clew position. If you streach the sail luff beyond those marks, you are likely to see a red flag appear on a nearby boat. Everyone wants the largest possible sail in light air, but that allows for no streach in heavy air.

GTJ

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Champipple
Master Marine Consultant

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Response Posted - 05/10/2002 : 12:24:02

Some more ramblings on this topic: (and I do mean ramblings)

With all due respect Greg, In light air I don't even want my cunningham on. I would remove my downhaul and cunninham, ease on the outhaul and even ease the halyards...Light and baggy...

But yes, to answer the original question. the cunningham tightens the luff without stretching the entire area of the sail. The boom downhaul and halyard would do both.

Interesting point to bring up the black tape lines. I've never knowingly raced a boat with a sliding boom, so the two points being fixed the sail max sail length was always preset. So I never even though of it because t didn't matter how hard you pulled on the halyard, you were always within specs.

As for the C-25, It too has fixed points. There is a cleat in the mast that will only allow the boom to drop down to a specific height...Stretch it all you want, I betya you won't be breaking the rules....Plus, there is no one design rule (for us) anywhere that says you can't stretch the sails on the C-25. The rule states that they need to be measured with enough tension to stretch the wrinkles and be within a certain guidline. It does not say anything about while on the boat. Nor do the Racing rules of Sailing.

dw

Duane Wolff
"The Flying Wasp"
C-25, #401 std,sk
Chief Measurer C-25/250 national Org.
<img src="http://im1.shutterfly.com/procserv/47b2dc20b3127cce9cd2f45b211a0000004010" border=0>

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Steve Milby
Past Commodore

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Response Posted - 05/11/2002 : 09:28:43

Duane, I knew there was a good reason why you were elected Chief Measurer by a historic landslide vote! You're right. Some one design classes require mast stripes to prevent stretching sails beyond a specified amount, but the C-25 rules do not. Moreover, one of the desirable qualities of the high tech sailcloths is that they do not stretch much. If dacron sailcloth is too stretchy, it wouldn't make very good sailcloth.

Steve Milby "Captiva Wind" C-25 T/FK #2554

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Ben - FL
Admiral

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Response Posted - 05/11/2002 : 19:02:13

I'm no expert, but I'm thinking that the cunningham grommet is not just pulling tension on the luff. That is, it isn't just pulling straight down. The grommet should be a little aft of the luff so that it pulls at a slight angle, there by flattening the sail.

For downwind, I use the topping lift to bag the sail.

Safe voyages,
Ben, FL s/v Chick-a-pea C250wk

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Champipple
Master Marine Consultant

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Response Posted - 05/13/2002 : 08:09:37

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
Duane, I knew there was a good reason why you were elected Chief Measurer by a historic landslide vote! You're right. <hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

Steve,

As much as I would like to think it was for all the reasons you infer above we all know it was because I ran unapposed!!!!!!!!!!!!

<img src=icon_smile_approve.gif border=0 align=middle>

Duane Wolff
"The Flying Wasp"
C-25, #401 std,sk
Chief Measurer C-25/250 national Org.
<img src="http://im1.shutterfly.com/procserv/47b2dc20b3127cce9cd2f45b211a0000004010" border=0>

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tinob
Master Marine Consultant

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1883 Posts

Response Posted - 05/13/2002 : 09:20:08

I've often wondered why, in the sixty plus years that I've been sailing, I've never raced nor felt any inclination to race. This thread just offered thirteen reasons for my decision. <img src=icon_smile.gif border=0 align=middle>

Val on "CALISTA" #3936
tall/wing
Patchogue,N.Y.

Val Bisagni

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Champipple
Master Marine Consultant

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Response Posted - 05/13/2002 : 10:06:33

Its only this difficult and petty on Land Val. On the water no-body gives a ........

DW

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Brooke Willson
Admiral

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USA
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Response Posted - 05/15/2002 : 13:12:32

Gee, I agree with Val again! That's really scary. . . for Val.

My life is too fast the rest of the time. The last thing I want to do on the boat is worry about how to go faster than somebody else.

But that's MY thing. No disrespect intended for those of you who race!

Brooke

Edited by - brooke willson on 05/15/2002 13:13:39

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n5lfy
Deckhand

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USA
15 Posts

Response Posted - 05/17/2002 : 12:15:26

Steve Milby and Derek Crawford, could you please post (or email to n5lfy@yahoo.com ) pictures of your downhaul and cunningham rigging? My boat did not include such rigging originally (optional I guess?) and I would like to see the examples of your boats prior to arranging my own rigging. I do like the idea of running the cunningham control back to the cockpit so that the luff tention can be adjusted "on the fly" as I go from a run to a reach. Thanks.

Edited by - on

Steve Milby
Past Commodore

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5902 Posts

Response Posted - 05/17/2002 : 13:59:35

I can't provide photos because my boat is, sadly, still on the trailer in my driveway, with a repair yet to be completed, but if you will click on the following hyperlink url]http://c25c250.best.vwh.net/restricted/pc19.gif[/url] it will take you to the C-25 parts catalogue, where the downhaul and cunningham are shown.

Notice that the slide on the gooseneck has a hole in the bottom. Tie a stopper knot in one end of a piece of line, and feed it through that hole. Then tie the other end of it to the black jam cleat that is situated in the mast slide, below the gooseneck slide. That's all there is to the downhaul.

On the same drawing, notice the line that runs through the cunningham hole in the mainsail. One end of it is attached to the cleat on the starboard side of the mast, and the other end is attached to a pad eye that is situated on the port side of the mast. (Because of the perspective, you can't see the pad eye, but it is situated at about the same height, on the port side of the mast, as the cleat is on the starboard side of the mast.) That is the cunningham assembly.

I hope that helps.

Steve Milby "Captiva Wind" C-25 T/FK #2554

Edited by - on

John Mason
Admiral

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Response Posted - 05/17/2002 : 15:05:38

Steve,
I think you are confusing the reefing system with the cunningham that may or may not be part of the main sail construction. The cunningham grommet (cringle), if it's even there, should be about 10" to 18" above the foot of the sail. The reefing grommet is about 36" to 48" above the foot of the sail.

John Mason - Ali Paroosa
1982 - FK/SR #3290

Edited by - on

Steve Milby
Past Commodore

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Response Posted - 05/18/2002 : 09:09:27

You're right, John. The picture depicts the line being used on the first reef. The cunningham hole would actually consist of a grommet set between the first reef and the boom. The hardware used for the cunningham and the reef is the same, however.

n5fly asked for a picture of the downhaul and cunningham hardware, and, since I don't have one, I used the picture from Catalina's parts catalogue, which shows the correct hardware, but it shows the cunningham hardware being used for a reef.

Actually, Derek's cunningham setup is undoubtedly better than the one that Catalina provides, because he says it uses a 3 part purchase, and that it is led back to the cockpit. The mechanical advantage would make it much easier to use in strong winds.

Steve Milby "Captiva Wind" C-25 T/FK #2554

Edited by - Steve Milby on 05/18/2002 12:48:32

Edited by - on

Champipple
Master Marine Consultant

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Response Posted - 05/20/2002 : 08:30:11

<BLOCKQUOTE id=quote>quote:<hr height=1 noshade id=quote>
The cunningham grommet (cringle), if it's even there, should be about 10" to 18" above the foot of the sail.
John Mason - Ali Paroosa
1982 - FK/SR #3290
<hr height=1 noshade id=quote></BLOCKQUOTE id=quote>

If you have a sail of newer design, the cunningham may attach by means of a hook through a loop on the sail. There may not be a cringle!.

DW

Duane Wolff
"The Flying Wasp"
C-25, #401 std,sk
Chief Measurer C-25/250 National Assn.
<img src="http://im1.shutterfly.com/procserv/47b2dc20b3127cce9cd2f45b211a0000004010" border=0>

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