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post #1 of 20 Old 06-20-2010 Thread Starter
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Helm Control

I have a C& C 99. 32ft with a large sail area. 6.5ft draft fin keel. The boat is equipped with a 48" destroyer wheel. When just slightly overpowered the boat becomes uncontrollable. She'll get into the grove then overpower. When I try to level off by pointing back to the wind, she won't go. The wind pushes the boat over to the point where I have no helm control at all. I can have the wheel turned all the way towards the wind and she still won't point back. We go out reefed most of the time and deploy only partial jib and still can find ourselves in the same situation in 12-15kt winds. Is there potentially something wrong here or is this normal for a boat of this design? Thanks. Spec
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post #2 of 20 Old 06-20-2010
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Check to see if the Center of effort of the sails have been moved. This could have been done the mast being moved forward or aft.

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post #3 of 20 Old 06-20-2010
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What condition are the sails in? It sounds like they may be older sails that have lost their shape and are blown out, which can cause the boat to heel excessively without producing much in the way of drive.

Also, what have you done to depower the sails?? Have you used the cunningham and outhaul to flatten them? Have you applied backstay tension to help flatten the mainsail and jib? etc...

A C&C 99 should be pretty good in 12-15 knots of wind without needing to be reefed.

It would help a lot if you had photos of the sails.

I'd point out that once many monohulls are heeled to a certain point, the rudder basically can't over come the forces on the boat that are caused by the asymetrical shape of the heeled hull. This one one reason a lot of monohulls sail much faster and with much better control when the sails are reefed in heavier winds—even though you have less sail area up, more of the effort is going to producing drive, rather than fighting the boat's progress through the water.

Another cause could be mast rake. Have you checked the rigging and how it is tuned on your boat and compared it to another C&C 99 or the specs for a C&C 99??

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post #4 of 20 Old 06-20-2010
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To me the C&C 99 has a 'design problem' ... the rudder when the boat is on a 'hard heel' isnt totally submerged, thus able to 'suck air' or 'cavitate' thus potentially losing its ability to steer.

To prevent the boat from losing the 'bite/control of the rudder' should be set up so that under normal conditions so that the boat has only a 'very slight' amount of (the apparent FEELING of) weather helm. All adverse helm pressure is NOT weather (or lee helm), it 'could' be a *SKID to leeward*:

1. TIGHT BACKSTAY - so that the jib luff and FORESTAY dont SAG OFF TO LEEWARD appreciably when windloaded. With a too-loose forestay any boat will begin to SKID off to leeward, will aggressively heel, will be SLOW, the wake will not be coming straight off the stern, and the boats performance will be very erratic and 'very cranky'. A boat skidding off to leeward will have a LOT of helm pressure (but it isnt 'weather helm') .... and any adverse pressure on the rudder (especially a rudder that isnt TOTALLY underwater) can create 'cavitation'.

2. Correct mainsail HALYARD/LUFF tension -
typically a mainsail with a **boltrope** needs to have the luff/boltrope additionally 'stretched out' after raising the sail. The additional 'stretch' on such a sail is usually 1" of *additional luff stretch* for every 11 ft. of mainsail luff length. Your mainsail luff dimension is approx. 35 ft. 35/11 = 3.2" that the luff needs to be stretched when sailing in ~15kt. winds (less stretch in lower v. winds). Note - when a mainsail is correctly raised and stretched, the angle that the upper surface of the boom makes with the mast is about 89-90 degrees ... if the luff is not stretched out then the aft part of the boom will be lower than the goose-neck and the draft will be aft, the leech will be 'hooked up to weather, and the draft will be 'very full'.
Note - a mainsail on a mast roller furler doent have a bolt rope, but the sail luff will/can 'stretch out' all by itself due to the windloading; so, in this situation the only way to control is to REEF.

2a. Next time out (12-15kts). Set up the boat normally to get proper trim, etc., go onto a hard beat to windward and LET GO OF THE WHEEL !!!!! If the boat wants to 'head up' then increase the MAINSAIL Halyard (and/or cunningham) tension until the boat neither heads up nor falls off !!!! This is a zero pressure helm pressure (dead fish helm). Once you 'find' the 'dead fish' helm position, then slightly release the halyard tension (an inch or so) so that the boat SLOWLY heads up when the helm is released.

If the boat has a short or 'shoal keel', these suggestions are extremely important, so that the boat doesnt skid off to leeward ... as the the next thing to happen after the rudder starts to 'suck air', the keel can also begin to 'trip' when it loses its 'bite'. When that happens .... you are soon going to get 'dunked' by either capsizing to windward or leeward when on a hard 'beat'.

;-)

Last edited by RichH; 06-20-2010 at 11:27 AM.
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post #5 of 20 Old 06-20-2010 Thread Starter
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The sails are orig equip Doyle sails (2003). Had them stored this winter with the local Doyle folks. They thought we could get a solid season or two more out of 'em. The Doyle folks basically said new sails would help a great deal. Your opinion please? As to rigging, I've tightened the outhaul and loosened the boom vang. The boat is not set up with a cunningham. In terms of de-powering the sails, I have a Harken Mainsheet system. I could let out the mainsheet to de-power the boat I suppose?? The mast was tuned last year. I agree with you and RichH re the rudder. I don't know enough about the engineering and design of the C & C to determine if there is design flaw, but we can easily lose control in 15kts of wind with one reef in and about 80% genoa deployed. I'm a new sailor, (2 years). The only other boat I have sailed with some regularity is an Alerion 38. In other words, I don't have much to compare to. The C&C's not slow, but she is a lot to handle and cranky as you point out. She never points back into the wind and as described when I let go of the wheel and we skid to leeward in moderate conditions. I'll try tightening the backstay as a first step. So to be sure I understand the rest of RichH response, after the main is raised, I need to stretch it out further after a few minutes underway. Your suggesting I could stretch out another 3" which will flatten the sail. Correct? The boat has a deep keel, 6.5'.
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post #6 of 20 Old 06-20-2010
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" Your suggesting I could stretch out another 3" which will flatten the sail. Correct?"

... the additional 'stretch out' only gets the sail to its 'as designed' shape (correct/designed fore/aft position of the point of maximum draft,, etc.).

To 'flatten', you have to primarily use the outhaul, etc.

If this is an 'old' boltroped sail, the boltrope may have changed dimensions (ie. shrunk along the length and got 'fatter' on the diameter).

To check, (in no wind conditions) raise the sail and ADD the needed additional halyard pressure, then measure the mast/boom angle. If that angle is significantly GREATER then 90 degrees, an 'adjustment' or 'easing' of the boltrope is indicated.
Depending on how severe the 'shrinkage' and how 'old' the sail, a new sail is sometimes the best way to correct .... depending on the 'involvement' in the 'easing or adjusting' of the boltrope length.

Woven dacron sails with a boltrope usuallly 'dont blow out', the 'bagginess' and draft aft and 'hooked-up leech' condition is usually because the 3 strand dacron boltrope has 'shrunken' along its length.
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post #7 of 20 Old 06-20-2010
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Quote:
Originally Posted by spec2 View Post
...but we can easily lose control in 15kts of wind with one reef in and about 80% genoa deployed. ....
A partially furled job will do nothing good for upwind sail performance. I would expect a lot of drag and fullness which would contribute to excessive heeling and lee helm. Try getting a smaller sail like a 110% up, with good halyard tension and the right lead position and see if your balance doesn't improve alot. A partially furled jib is not an upwind sail.

And your halyard and outhaul settings should be determined by the black bands on your spars, those are full-on positions.

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post #8 of 20 Old 06-20-2010
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Quote:
Originally Posted by sailingfool View Post

And your halyard and outhaul settings should be determined by the black bands on your spars, those are full-on positions.
Nope, thats ONLY true if the sailmaker constructed the sail exactly to meet 'class rules', etc. and he/she also actually measured that the 'bands' were 'accurate' and in compliance for the class, etc. Most sailmakers ignore 'the black bands' when they actually measure ...unless the client specifies 'racing sails' for racing. Stock or plain vanilla cruising cut sails are 'dimensioned' from 'stock OEM database' derived from the boat's designer info.
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post #9 of 20 Old 06-20-2010 Thread Starter
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Thanks for the responses and good advice. I'm not sure if my sails are bolt-rope sails but will take a closer look next time I'm out. The sails don't have creases in them underway which if I'm not mistaken is a tell-tale sign of shrinkage?? RichH, any advice on how best to measure mast/boom angle to ensure 90 degrees? Btw... the sails have slugs that run in the mast and boom. Sailingfool....thanks for the guidance on the partially furled jib. I had thought a partially deployed sail would provide for greater control, but as you point out, that is not the case.

Maybe its time to drag my sailing experts out with me along with a visit to the Doyle folks for a quote.
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post #10 of 20 Old 06-20-2010
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Reefing..

I don't know what size headsail you're running, but if you're running a huge headsail (130%+) and reefing to 80%, you have an effective area of about 105%, but the sail is less effecient and no where near as good as a true 105% sail. If you're head sail doesn't have a foam or rope luff pad, rolling it up results in a very poor shape and doesn't act as a sail but instead as a bag to catch wind. This is why you just blow over.

Also you say you have huge weather helm above 12+ kts apparent. If I read your post correctly, you reef the main AND headsail. Don't reef the main. As counter intuitive as that sounds, you problem is the wind pressure on the sail area forward of the center point, couple with the fact that you have an ineffeciant airfoil on the front (bag), and reduced area in the back (main sail) results in less aft center point sail area. This is why you can't turn the boat when heeled over.

Run this experiment. Next time your out in 12+ kts wind, furl or drop your headsail and run only on the main sail at a closehauled course. Does your boat handle the same? If you have the main only up, does you boat blow over and if so, when you turn the wheel into the wind, does the boat now head up? If so, then you need to run a smaller headsail that isn't reefed. Yes, something else is going on.

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