Advice on sails, size and ballance

[ProDave]

We are coming to the end of our first season sailing, and now turning our thoughts to what alterations / improvements we need to make to the boat over the winter.

The first is looking at the sails we have and deciding if we need to change anything.

We have been sailing all year with the sails that were on the boat when we bought her. They are clearly not the originals (though I think the very tatty pair we have in a bag under the bunk might be)

So our "problem" with the sails I think is weather helm. It's only a problem when sailing close hauled in light winds.

Under these conditions to keep the boat going straight, then (when sitting on the windward side of the boat) I need to pull the tiller a long way towards me. If I let the tiller go straight, then the boat will turn into the wind and stall.

This is only an issue in light winds and when close hauled. Stronger winds or a beam reach and she feels more balanced.

We have played around with sail trim to try and improve things, and I think I have formed the opinion that the jib is over powered. My reasoning for that (remember this is close hauled sailing) is that if we let the jib out a bit, sometimes to the point where it's luffing, then the boat balances up and we can sail with the tiller pretty much straight.

The other factor that swings me to that thinking is that it's clear the main we have on is a little too small for the boat, i.e the head of the sail is about a foot short of the top of the mast.

I haven't measured any of the sails yet, but will do soon when the boats back home for the winter, then I can compare the sail areas we have with what they should be (according to the original brochure for the boat)

But before we go looking to change either of the sails, I wanted some advice. Are we on the right lines with my thinking?

 

[dt4134]

Would I be correct in guessing you have a Frolic 18?

I'm afraid I don't know the boat so can't make any specific comments.

A headsail can cause weather helm, especially on hulls that are unbalanced when heeled, however you're saying that the weather helm only occurs in light airs, so it is probably not caused by heeling.

Another possible factor is having a huge genoa, which was the sort of thing people did with masthead rigs in the IOR era. That can give weather helm. Do you change to a much bigger headsail for light airs?

After that it is mainsail trim. It usually works the other way around that when the wind picks up the mainsail isn't suitably flattened and you get weather helm. Old sails are harder to flatten which is where they are more likely to induce weather helm.

As the problem occurs in light airs, bagginess shouldn't be a problem, in fact to a certain extent it is desirable.

How do you trim the main in light airs? You should go for more twist and you shouldn't normally have the boom above the centreline. If you have a traveller you'd move the car up the track and ease the sheet to let the boom lift a bit and give you more twist. Without a traveller you can sort of do it using the topping lift to lift the boom if you can be fussed to do that when cruising.

The other question is to ask what you consider light airs.

 

[Skysail]

This seems an odd situation. A bigger mainsail would normally increase weather helm as it tends to round the boat to windward. The jib in your photos does not look big enough to induce weather helm; a baggy overlapping genoa can cause it.

Are you sure that when sailing to windward you are pointing as high as you can? The jib should be on the point of luffing if you have it right. If you pull the tiller to windward it will feel like weather helm, but the boat will sail off the wind.

The other factor you might consider is mast step position and rake - too much rake, and a mast too far aft can cause weather helm.

There are other factors like fore and aft trim.

I would also talk to a sailmaker.

 

[Giblets]

Dave, if it's any help when I was out on my little boat during the high winds at the beginning of September I had the storm sail rigged all the time with full main. She was perfectly balanced even to the point that I could leave the tiller and she would sail in a straight line for quite a while only getting deflected by the sea state.

 

[ProDave]

I'll try and answer all the points raised.

Yes it's a Frolic 18, which is a quite rare little boat that few people know anything about, but if it's relevant, she is quite beamy for the length at 8ft wide.

The conditions I was describing were in light winds. By that I mean just about as light as it's possible to sail in, so heel was definitely not contributing to the problem.

We only use one headsail and it's not massive, it doesn't overlap the main by much.

We don't have a mainsheet traveller, so when sailing as high as we can, the main sheet is pulled in tight and the boom pretty much along the centreline. Yes we are sailing as high as we can, if we try and pinch any further the main starts to luff and we loose speed.

Mast rake may be an issue. I had a thread before the beginning of the season where I looked at that. With the boat as we got it, the mast was raked too far aft to the point it was impossible to tighten the two lower shrouds that are slightly aft of the mast centreline. To enable those shrouds to tighten properly, I removed a spacer that had been inserted in the forestay. The mast now looks bolt upright, but as it is, those two lower shrouds are tightened with their bottlesrews fully tightened. In other words I shortened the forestay only just enough to tiension the lower shrouds, so perhaps I need to ease those off a bit and tighten up the forestay a litte more.

Perhaps we don't need to do anything with the sails, other than learn a bit more about sail trim?

 

[CreakyDecks]

Strange. I get the exact opposite effect. In very light winds I get lee helm. In "normal" winds I get slight weather helm. I thought this was fairly normal behaviour. I can't see how a jib overpowering the mainsail can turn you towards the wind. (Mind you I am still learning and clueless!)

 

[ProDave]

Strange. I get the exact opposite effect. In very light winds I get lee helm. In "normal" winds I get slight weather helm. I thought this was fairly normal behaviour. I can't see how a jib overpowering the mainsail can turn you towards the wind. (Mind you I am still learning and clueless!)

Now you have got me thinking. Perhaps I was having to push the tiller away from me? Perhaps I was getting lee helm?

All I can be certain of, is I was having to push the tiller a long way to keep the boat on course, letting the tiller go caused the boat to round up into the wind, and letting the jib out balanced the setup and allowed the tiller to be nearer the centre.

My basic question is, do I need to change my sail plan, or is this just normal?

 

[SAWDOC]

Keep looking and keep asking questions.
With our own boat, I notice that with our large genoa, we experience weather helm with light winds and when wind goes above 12 knots or so our boat will bear away (lee helm) if the tiller is left unattended. Before I make the expensive decision to order new sail or recut sails, I am of a mind to bring our good local sailmaker on board to hear what he has to say

 

[theoldsalt]

ProDave,

Have you dug out the old set of sails and compared them to the newer ones even to the point of fitting them and sailing to see if they are different sizes/shapes?

 

[gardenshed]

Prodave
Go along to Lossiemouth sailing club and ask to crew for one of the boats in their winter series of Sunday races. That way you will learn more about sail trim and sail shape and meet folk that can help you more than posting on any forum. It's a very down to earth club and you won't have to join if you are just crewing for a few races.
You may even be able to persuade someone to come out for a sail with you and give you some instruction.

http://www.lossiecc.co.uk/

 

[William_H]

Weather helm

This is indeed a strange story in that weather helm is usually a problem at stronger winds higher boat speed.
If your problem is very low speeds and wind strength you presumably pull the tiller a long way to make it go straight.
At low boat speeds the rudder has less effect so you may think you have to pull the tiller further. This can be a bad thing because the rudder can stall from too much angle of attack so loses effectiveness.
I wonder is the hull clean? A build up of weed can make a hull do strange things. Real weather helm really requires a hard pull as much as a large pull. (but still not much angular change.
At low speed also the sails can sometimes take control of the boat.
I can only suggest you do more sailing and check again the effects you speak of. If you don't have enough speed of water over the rudder you could get very confused. Make sure the boat is trimmed level fore and aft and abeam. Then with a small but stable wind take note again of what the boat wants to do.
I suspect you are just confused by various forces in really light conditions.

As for sails don't rush to buy new. However if you feel windward performance is poor a new jib is most likely to improve pointing. Do you use a furler? Individual jibs can generally work better to windward. If you use hank on you might find the heavier wind working jib is the one to consider replacing. The genoa for light winds will be OK even if stretched. good luck olewill

 

[Seajet]

Dave,

I think you may be onto something when questioning whether it's weather or lee helm you've got.

If sitting on the windward side opposite the sails, weather helm means you're having to pull the tiller towards you all the time to get the boat going straight.

Lee helm, you'll be having to push it away all the time and is an uncomfortable feeling; slight weather helm is desirable so the boat will stop if the helm is left untended, worst case being you've fallen overboard.

If you imagine the boat pivotting about her keel and underwater profile, that's the centre of Lateral Resistance.

The Centre of Effort is the sum point where the sailpower may be said to exert its' load ( varies on different points of sail ).

If the C of E of the sails is far behind the pivot-point CLR, it will push the stern downwind, weather helm, while if the C of E is forward, it will push the bows downwind.

Usually in light airs with a relatively large genoa one may well experience lee helm until the boat picks up speed; I suspect this is what you've got.

 

[Simondjuk]

I imagine it's weather helm, since there's mention made of the boat rounding up to wind if the helm is let go. If it were lee helm, the boat would bear away.

Here it is:

If I let the tiller go straight, then the boat will turn into the wind and stall.

 

[Skysail]

All I can be certain of, is I was having to push the tiller a long way to keep the boat on course, letting the tiller go caused the boat to round up into the wind, and letting the jib out balanced the setup and allowed the tiller to be nearer the centre.

My basic question is, do I need to change my sail plan, or is this just normal?

Dave you have made 2 different statements.... you need to decide if you are pushing or pulling the tiller. Either way, in light winds, a lot of weather or lee helm is not normal. If the boat rounds into the wind that is weather helm.

 

[Seajet]

I was going on / confused by this bit;

-----------

"Now you have got me thinking. Perhaps I was having to push the tiller away from me? Perhaps I was getting lee helm?

All I can be certain of, is I was having to push the tiller a long way to keep the boat on course, letting the tiller go caused the boat to round up into the wind, and letting the jib out balanced the setup and allowed the tiller to be nearer the centre."
------------

Perhaps we should establish which side you're sitting Dave, we were generally assuming you'd be on the windward side opposite the sail ?

 

[Simondjuk]

Ah! I see the confusion between whether he's pushing or pulling now. Regardless of whether a push or pull is required dependant on which side of the boat he's sitting on, I'm still guessing it's weather helm, since he describes the boat rounding up.

If it were lee helm, and the boat were bearing away from close hauled, I'd have thought the initial acceleration, dramatic increase in heel as the wind came on the beam and hard-sheeted sails and (whilst in reality the boat would probably head up again as she became overpowered) potential eventual gybe if she did continue to fall off the wind would have been dramatic enough to stick in the mind.

 

[Seajet]

Simon,

I agree overall it sounds like weather helm, re. the rounding up.

For info' my Anderson 22 ( 7/8ths rig, 135% overlapping genoa ) does exhibit lee helm to windward with the genoa in very light airs, but once moving significantly becomes neutral then slight weather helm.

 

[ProDave]

Ouch my brain is hurting. I wish my memory was better to recall exactly what behaviour we experienced in light winds, in particular which way I had to push the tiller to keep her going straight.

Sadly it's looking like with this run of cold windy wet weather at the moment that we won't get another chance to go sailing before crane out next week (and if we do it's extremely unlikely to be in light winds)

All I can be 100% certain of was depowering the jib, to the point of it luffing, balanced the boat and enabled me to steer a straight course with little input from the tiller, which is what led me initially to think the jib was over powered compared to the main. I am also sure that letting the tiller go, caused the boat to round up into the wind and stop. The bit I can't be sure about was whether I was pushing, or pulling the tiller to keep a straight course. I always sit on the windward side of the boat when helming.

Once I get the boat home, I'll measure all the sails, including the very old tatty ones. Yes it might be worth flying the old tatty sails once jut to compare how she handles, but it would have to be when nobody was watching because they are very tatty looking.

I think the thread is now becoming a bit pointless because my recollection of the facts is unclear, and without clear information nobody can give clear advice. That's unfortunate, as that probably also means I can't make any decisions over the winter what, if anything to change, so it might all have to wait until next spring.

The one thing that sticks in my mind that does not make sense to me, is the fact that depowering the jib balances the boat, but surely in light winds people fly over sized jibs? it would look as though if I tried that I would have a boat that I couldn't steer?

 

[temptress]

Now you have got me thinking. Perhaps I was having to push the tiller away from me? Perhaps I was getting lee helm?

All I can be certain of, is I was having to push the tiller a long way to keep the boat on course, letting the tiller go caused the boat to round up into the wind, and letting the jib out balanced the setup and allowed the tiller to be nearer the centre.

My basic question is, do I need to change my sail plan, or is this just normal?

This would be normal behaviour in light airs. You may get less if you change your sails but you will get a whole lot more if you tune your existing rig and trim your sails correctly.

I recommend the North sails book 'U Trim' as a good investment before getting new sails. This will help you understand how to set-up your rig and get the best out of your existing sails.

 

[Seajet]

Dave,

as you say it's tricky to diagnose without a clearer idea.

The conflicting bit is that de-powering the jib gives a balanced helm, which says lee helm - if you recall my mention of the boat pivotting around the keel, and sails acting fore or aft of that point.

BUT, if letting go of the tiller causes her to round up into wind, that's weather helm !

Well it's something to look forward to sorting next season, like others here I'd definitely recommend reading up on the subject, NOT investing in new sails, kit, or making any changes for now.

One thing you could check before she comes out of the water, is the mast particularly raked ?

Usually, if you let the main halliard fall from the masthead ( maybe with a spanner or something shackled on if there's any wind ) it should fall a few inches aft of the mast, this is a very rough guide.

As mentioned previously boats do handle quite differently in very light winds, when they have trouble converting wind effort into forward drive, and the boat is steered by the sails until she gets moving.