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  #1 (permalink)  
Old 07-10-2007
Julie303 Julie303 is offline
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weather helm on Pearson 303

Help, help! I'd like to pick anyone's brain at this point! I have an '83 303 with a 140% jib. The main is original (I think) and the jib is about 4 years old. Problem: with just the main up, I have a weather helm (understandable); with just the jib up (140%, 100%, etc.) I have a weather helm (not understandable). With both up and running with about a 15 kt wind, I have so much weather helm that I can hardly hold her straight! This is not right!
The obvious fixes would be: Move the mast forward some (not possible, because the roller rigging isn't adjustable), or buy a new main ("pocket" in a more forward position). I have friends who have really sweet-sailing 303s that have a neutral helm. I want a sweet-sailing boat like all the other kids . Any thoughts on the matter, anyone?
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Old 07-10-2007
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Tighten your forestay

Rick in Florida
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Old 07-10-2007
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Have you tried flattening the main, using the halyard, outhaul, cunningham, boom vang?? If you have, then it is likely that your main is blown out and really should be replaced.
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Old 07-10-2007
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I have a feeling that this may well be more rig tune than anything else. If you have weather helm when under headsail alone the it sounds to me like you entire rig is too slack. How is the forestay tension ? If it's slack then tighten up on your backstay and see how you go. One other thought is headsail block position. You might need to bring the lead further aft in order to flatten the headsail. Once you have the weather helm sorted out for your headsail then move onto the main.

Your now tightened forestay will help to flatten the main and so you may well find that all is well. If it improved but is still more WH than you'd like , and having checked your outhaul and halyard tension, then where is your mainsail sheet block ? In over 15 knots the car should be right down to leeward so that you depower the main but can still keep the boom low. Judicious use of your vang will also assist in keeping boom under control as well.
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Old 07-10-2007
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Are you sure there is no way to move the mast forward by tightening the forestay and backing off on the backstay? Worth trying.
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Old 07-10-2007
RichH RichH is offline
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The P303 is quite sensitive vs. weather helm to sail SHAPE.

The P303 will quite adequately sail to weather with genoa alone ... and still have some weather helm IF you 'really' know how to 'set' and 'shape' the sails. Sailing a Bill Shaw designed Pearson - its easier to sail on just a genoa than reef the mainsail !!!!!!!!!!
Bill Shaw really knew how to design a boat and a P303 will sail along nicely and without much perceptible adverse helm ... but you need to 'balance' the sailplan (actually - correctly 'set' the position/location of maximum draft - which is positioned by applying the ***correct halyard tension***).

The CE of a designers sailplan is only a 'concept' and is **only** valid if the boat is sailing perpendicular to the wind. The 'actual' CE is a *dynamic* balance of the interaction of the two sails and is more dependent on where the position of maximum draft is located by the sailor who properly 'stretched-out' the 'preload' in the boltrope(s) by correct halyard tension. If THAT fails to get you proper helm, then and ONLY then does one begin to think about raking the mast, etc. MOST sailors simply 'raise' their (boltroped) sails and never correctly 'stretch out' the luff boltropes ( ........ and then complain of 'weather helm').

A too loose forestay (adjusted by tensioning the backstay) will give a set of symptoms similar to 'weather helm' ... actually, too loose a forestay sets the boat skidding off to leeward, gives a LOT of 'side-pressure' on the rudder/helm which you THINK is weather helm .... makes the boat HEEL and additionally gives difficulty when trying to 'point' or come through the eye of the wind when tacking. Make sure that the rigging especially the forestay/backstay is *tight* .... 18-20% of tension if you are using a tension guage.
Another way to *match* the forestay sag with what the sailmaker 'designed' into the jib/genoa sail: take the genoa and lay on FLAT ground; make a double accordian pleat fold about 2ft. back from the luff ... this will allow the sail luff section to lay unwrinkled and FLAT on the ground with NO wrinkles within 3 ft. of the luff section. Then take a string and stretch it between the head of the sail and the tack .... then measure / remember the maximum distance of the 'curve' that the sailmaker put into the luff of the jib/genoa at the luff (called 'luff hollow' - to *match* normal forestay sag) ..... and when sailing at 15-18kts on a beat that maximum 'curve' you measured/remembered in the shape of the genoa luff should ***MATCH*** the sag that you get in the forestay !!!!!!!!!!!!!!! If the forestay sag is greater than the hollow-curve (that you measured) that the sailmaker put in ... you get the symptoms of WEATHERHELM as the boat skids-off to leeward as it aggressively heels over!!!!!!!

Do the following:
1. If the mainsail is original, the luff boltrope is probably 'shrunken' (shorter due to age than when originally installed). This is probably the CHIEF cause of weather helm when using a dacron sail (with a boltrope in a sleeve) at the luff.

1a. Remove the mainsail and lay it on FLAT ground with the luff straight, then accurately measure the luff length. For a P303 the luff should be 34 ft. 8 inches EXACTLY. Then measure the angle that the luff makes with the foot of the sail ... should be 88 degrees, exactly.
if the luff length is much less than 34.ft, 8 inches or the angle between the luff and the foot is much GREATER than 88 degrees, then the three-strand luff boltrope is shrunken and should be 'eased' by a sailmaker.

A shrunken boltrope will cause the point of maximum draft to be located too far aft (giving weather helm), the leech will be 'hooked to weather' (giving weather helm) and the sail will be radically 'too full' (giving lots of heel but no 'go').

1b. If the luff dimension is 'close' to 34ft. 8 inches then you are probably not raising the sail properly!!!!! ... and you will get the 'shape' as outlined in 1a. above. A sail with a three-strand bolt rope is constructed with the bolt rope purposely shortened by 1 inch for every 10-11 ft. of luff length and is done so that when a dacron sail is wind-loaded at approx 18 knots you dont 'overstretch' the sail cloth. Therefore, once you 'raise' the sail, and intend to sail in ~15kts of wind you must: additionally 'stretch' the halyard (luff) another 3.5 to 4 inches ... after 'raising' the sail .... this will remove the boltrope 'preload' (shortening) that the sailmaker subtracts from a dacron boltroped sail targeted for 18kts. max. wind. ... The sail luff should be 35ft. 0 inches when raised AND the luff boltrope is 'properly' and additionally 'stretched'.
A 'good' sailmaker will also additioinally adjust the boltrope so the sail is maximized for venues with FLAT water (1-2ft. waves) or for venues with lots of 'steep chop', etc. (you dont get this from a 'mail order' sail loft).

1c.
Setting the mainsail (with proper boltrope dimension) for proper 'helm balance':
In 12-15kts of wind with the genoa flying, raise the mainsail, add ~3.5 inches of additional luff 'stretch' .... and then notice the helm balance when on a beat. If you still have weather helm .... keep adding halyard tension until the helm becomes totally ***neutral*** when beating; then reduce halyard tension by 1/2 inch increments until you properly affect a 'very slight' bit of weather helm. Your P303 will begin to 'fly' at this point (rudder angled just a 'degree or two to leeward' ... and you will probably note that the boat is 'climbing' towards the wind as the keel is now 'lifting' towards windward and the boat is now 'pointing' like a banshee!!!

If the mainsail luff and tack angle dimensions are out of whack ... simply get a sailmaker to 'ease' the boltrope. A mainsail with a shrunken boltrope when raised and 'improperly' stretched (or not stretched at all) at the luff boltrope ..... will have the aft end of the boom LOWER in the horizontal plane than the gooseneck !!!!!
Raise the sail, then stretch that boltrope/halyard an additional 3.5+ inches ... then get OFF the boat and 'see' if the aft end of the boom is lower than the gooseneck. If the aft end of the boom is LOWER than the gooseneck then you probably have a severely shrunken boltrope, ... take it to a sailmaker to have that boltrope 'eased' .... a fairly 'simple' and fairly inexpensive 'fix'.

I design and make my own sails, sail hard ... and have to 'ease' the boltropes after every season of hard sailing. A P303 is a 'very sweet' sailing boat and should have an ever so slight (almost imperceptible) weather helm ... IF and ONLY IF you have the sails correctly set with correct halyard tension (and dont have (very common) shrunken boltrope in the mainsail).

The SAME applies to virtually all boats with woven dacron sails with dacron three-strand boltropes at the luff .... and are complaining of 'weather helm'.

Hope this helps. ;-)
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Old 07-10-2007
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Rickm505 Rickm505 is offline
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Rich

Great post. When I bought my boat she had so much weather helm she was almost uncontrollable. I instantly related to Julie303's post.

Two factors corrected my problem. a tighter forestay and slightly decreased mast rake. She handles like a dream now. I'd look to rigging tune before taking out my checkbook.

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Old 07-11-2007
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Good stuff RichH, thanks
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Old 07-11-2007
RichH RichH is offline
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Rickm505

ALWAYS .... when having 'problems' with sails, helm, etc. .... reset the rigging tension to 12%... (unless you tell the sailmaker that you're at different rigging tensions), as the sailmaker is just going to 'assume' that 12% rigging tension ... and that tension will be included in the sail design/calculations for luff curves, etc. etc. etc. If your rigging isnt near that 12% value the sail is NOT going to be anywhere near the designed shape. increasing backstay(forestay) ensions will flatten a jib/genoas shape ... at much less than 12% (forestay) the genoa shape will be like a bellowed out 'pillow case'. 12% is good, tighter is usually better for upwind performance ... 30% forestay/backstay is probably the max. for beating upwind and you need a flattened shape with lots of draft pulled out of the sail.

Mast rake is usually the 'last resort' in sorting out 'helm problems' because if you misbalance with mast rake and leave a badly shaped (poor max. draft location) sail up ... the boat is going to be 'cranky' because you 'balanced' but didnt remedy the 'problem'.
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