Fixing lee helm

[sighmoon]

This is my son sailing Bobby on the one sunny day we had last year. Bobby is a Seahopper.



He's trying to sail to windward, and you'll note the helm is a long way down. He's not in the middle of a tack; there's a lot of lee helm, and consequently progress to windward is dire. Tacking was very difficult - generally he had to gybe round.

If you look closely, you can see that the shrouds are twisted - i.e the port shroud comes round the front of the mast to the starboard side and vice versa. This was to try to shorten them, but it still wasn't right.

Is getting a few inches off the shrouds the answer, or should I try something else?I've never tinkered with a gunter rig, so I'm not sure if the sail is rigged right. It doesn't look right - the bottom half of it is vaguely sail shape, but the top is flapping. Yes, there's a lot of mainsheet left to pull in, but when he did this, progress was more sidewards than forwards. If he alters course to fill the top of the sail, then he's no longer sailing upwind at all.

Any ideas?

 

[PaulJ]

I can't claim to know much about small dinghies but....... did he have the centre board fully down?

Paul

 

[jwilson]

I can't quite see what is wrong with the sail set on the gunter yard, but something is messing up the luff tension. Also the outhaul is way way too tight, and the lee helm would reduce, and the sail fill and drive much better if the hull was heeled maybe 10-15 degrees to to leeward not 5 degrees to windward as it is, and the sail sheeted in slightly more - not too hard though.

 

[Gin]

At first glance and comparing the angle of the gunter spar visible in your picture with that of the Mirror dinghy, I reckon the problem is caused by the spar not being sufficiently close to the mast i.e. not hauled in tight enough, which allows the top section of the mast to sag due to a lack of tension.

Take a look at a Mirror to see what I mean

https://www.google.co.uk/search?q=m...Ln6Q95qqM:&usg=__T_zga4qON2W_EHwmVG229G6dhO0=

 

[LadyInBed]

A bit of wind might help!

 

[KellysEye]

The sail shape alone would cause problems it must be flat.

 

[DanTribe]

So many things to check, it's hard to know where to start.
Firstly it's much more difficult to sail a low performance dinghy than one that wants to sail.
The boat doesn't seem to be moving much so perhaps no steerage way. Possibly pinching [to close to the wind] A rig like that will not do much better than a reach. Try sailing off the wind and keep some speed up.
Try sitting further forward, the trim looks stern heavy.
Sort out the sail. That crease is bad,. Try, a]moving the halyard further down the yard, b] even out the tension on the lashings. c] more throat or downhaul tension. d] bin it.
That boat is never going to be a flyer but you could have some fun trying to get it to move. If Bobby is just learning to sail, you would do better to get a dinghy that gives some feedback, e.g. Optimist, Mirror, Cadet, lots of cheap starter boats out there.

 

[nickd]

That crease in the sail extending from the outhaul at about 45 deg is wrong, I would guess the outhaul is way too tight. With that sort of rig I would doubt you can get much closer than 70deg to wind, if you added a kicker with about a 6:1 purchase (see if you can borrow one from a topper owner (easy enough to but a temporary fixing point on boom with some rope and tape) and haul it on so hard the boom starts to bend you will probably get a lot higher, provided it has a centre board without which you are always going to go sideways.

 

[TSB240]

This is one obviously nicely set up!

https://lh5.googleusercontent.com/-...SXQM/w2048-h1365/14756982678_4f5b3ad399_k.jpg

 

[johnalison]

Needs some weight in the bows. Young sister would do.

 

[lw395]

Needs some weight in the bows. Young sister would do.

Get a tiller extension, sit forward and to leeward. Failing that, weight the bow.
Are there supposed to be battens in the sail?
Get the gaff up harder.
Apply a little luff tension.
You might start off with the boat on its side to sort out a reasonable sail shape.

I'm assuming the daggerboard is present and fully down?

Starting off in really light wind can be a bad idea, the boat will respond better in a usable breeze.

 

[sighmoon]

Thanks for the many responses. Interesting that the verdict seems to be sail shape rather than raking the mast back as I'd thought.

did he have the centre board fully down?

Yes

I can't quite see what is wrong with the sail set on the gunter yard, but something is messing up the luff tension. Also the outhaul is way way too tight, and the lee helm would reduce, and the sail fill and drive much better if the hull was heeled maybe 10-15 degrees to to leeward not 5 degrees to windward as it is, and the sail sheeted in slightly more - not too hard though.

Leaning it didn't help much. Sheeting in made it go sidewards.

At first glance and comparing the angle of the gunter spar visible in your picture with that of the Mirror dinghy, I reckon the problem is caused by the spar not being sufficiently close to the mast i.e. not hauled in tight enough, which allows the top section of the mast to sag due to a lack of tension.

Take a look at a Mirror to see what I mean

https://www.google.co.uk/search?q=m...Ln6Q95qqM:&usg=__T_zga4qON2W_EHwmVG229G6dhO0=

I reckon you're right.

A bit of wind might help!

Tried that.

The sail shape alone would cause problems it must be flat.

So many things to check, it's hard to know where to start.
Firstly it's much more difficult to sail a low performance dinghy than one that wants to sail.
The boat doesn't seem to be moving much so perhaps no steerage way. Possibly pinching [to close to the wind] A rig like that will not do much better than a reach. Try sailing off the wind and keep some speed up.
Try sitting further forward, the trim looks stern heavy.
Sort out the sail. That crease is bad,. Try, a]moving the halyard further down the yard, b] even out the tension on the lashings. c] more throat or downhaul tension. d] bin it.
That boat is never going to be a flyer but you could have some fun trying to get it to move. If Bobby is just learning to sail, you would do better to get a dinghy that gives some feedback, e.g. Optimist, Mirror, Cadet, lots of cheap starter boats out there.

He managed to reach easily enough, but getting back from a jaunt downwind proved very difficult.

We chose Bobby because she folds flat, so we can take her with us on the mother ship and nipper can go sailing while we're moored.

That crease in the sail extending from the outhaul at about 45 deg is wrong, I would guess the outhaul is way too tight. With that sort of rig I would doubt you can get much closer than 70deg to wind, if you added a kicker with about a 6:1 purchase (see if you can borrow one from a topper owner (easy enough to but a temporary fixing point on boom with some rope and tape) and haul it on so hard the boom starts to bend you will probably get a lot higher, provided it has a centre board without which you are always going to go sideways.

I'll work on getting rid of the crease first off then.

THe outhall was tightened like that to try to fix the problem. Evidently it didn't, but a loose outhall didn't work either.

Needs some weight in the bows. Young sister would do.

Dad's 70+kg didn't sort it

 

[VicS]

Thanks for the many responses. Interesting that the verdict seems to be sail shape rather than raking the mast back as I'd thought.

Based on sailing a Mirror ( now and then) with only the mainsail


I would set the mast vertical, or very slightly raked aft.

Hoist the gaff up tight against the mast. You might have to think about the best way of attaching the halyard . (I dont use a shackle but IIRC very small shackles were available)

Tighten the luff by adjusting the lashing from tack corner to boom to just create a slight crease down the luff. ( Or with the boom down haul if that's what it has)

Tighten the outhaul to leave a little slack in the foot.

Above all else get rid of that diagonal crease


The Mirror it must be said has two mast steps ( and two pairs of shroud plates) One for normal use when a jib is in use and another 10" further forward to use when a jib is not used


You will not point very high as others have said and you will need to pick up a bit of speed to tack the boat but it should not suffer from lee helm. I'd have thought tacking would be easier than gybing if every thing is set upcorrectly.

 

[lw395]

Are you sure the mast is in the right place?

Mirrors have a forward mast position for when you're not using the jib.
But TBH, that sail is a mess.
It looks like battens are missing making the leech an unsupported flap? Or are they there but broken or too short?
You need to get it setting to a reasonable curve with no mega-creases. You should be looking for something like a curve with around 5-10% draft to chord ratio, with the max draft between 30 and 50% back from the mast. (That's to basically function, not to win races!).
There should be a fair curve from front to back at any height up the sail.
Small creases, much less than the draft in depth are a fact of life.
The leech needs to be supported by the battens if there are any.
The whole of the sail needs to be sheeted to a similar angle of attack to the wind, maybe the top twisted off 5 or ten degrees, not much more.
The gaff needs to stay put when you pull the sheet in, not fall away from the mast due to halyard stretch.

Rigging it on its side you can check all that and try to get the best compromise of tensions.
It will be a compromise, that sail looks pretty tired, but you should still be able to make it function.



Also, things can go wrong in a small boat if you stall the sail. Get moving, then head up, keeping flow attached. A stalled sail will often have lee helm.

As a sanity check, the centre of effort of the sail will be around 30% back from the luff. Where is the centreboard in relation to that?
Also check there is nothing under the water causing gross drag.

Also, a reasonably set up Mirror with just the main should point higher than 50 degrees to true wind.

But bear in mind that compromised, slow boats are not the easiest to learn on. A few lessons on something that works better might be worthwhile?
A better sail might be an investment, maybe something else would fit?

 

[dunedin]

Agree about the sail shape and getting the gunter up tighter. In a Mirror (pre Bermudan rig) the golden rules were:
- never use a shackle on the halyard - just a very small halyard fitting thread halyard through and tie a knot
- never ever ever tension or tie off the outhaul, down haul or luff lashing until AFTER the halyard is hoisted and fully tensioned. Only then adjust the downhaul, then tie the luff loosely and finally adjust the outhaul (this is the most common setup error with Mirrors)

Not sure however that this will make much use in this case. It might, but I wonder if this boat was ever designed to sail properly. Probably need a bigger sail and perhaps moving the dagger board forward to move upwind?

 

[VicS]

I recommend the Ladybird book Learnabout "Sailing and Boating"

Its a kids book but very well written and difficult to fault.

There are always several available on ebay........ but dont pay silly money for one. With luck you'll get one for well under a fiver including postage. (past experience has shown that a mention on thess forums can start bidding wars for them .... wait until things return to normal)

 

[sighmoon]

Are you sure the mast is in the right place?

It's where the builder put it, but no, I'm not sure it's right.

No batten pockets. I'll play with the main on its side as suggested.

 

[DJE]

We've got an 8' dinghy with a similar rig. Goes to windward beautifully. If you row it!

 

[JumbleDuck]

The Mirror it must be said has two mast steps ( and two pairs of shroud plates) One for normal use when a jib is in use and another 10" further forward to use when a jib is not used

I have a Ferrantiboat 10 (for sale, cheap, as it happens) which uses a Mirror rig but which only has one mast step. I discovered, when I first tried to sail it, that with main only and in light winds it has completely uncontrollable weather helm. The boat never goes fast enough (light winds) for the rudder to be able to counteract the rounding up moment of the sail (centre of effort too far back). When the wind is stronger things improve and with a jib it's absolutely fine.

That aside, with stuff-all wind and a sail as horribly shaped as the OP's, I'd take any wind-induced movement as a welcome surprise and be thankful for it. Wanting any form of directional control as well seems a bit greedy.

 

[lw395]

I have a Ferrantiboat 10 (for sale, cheap, as it happens) which uses a Mirror rig but which only has one mast step. I discovered, when I first tried to sail it, that with main only and in light winds it has completely uncontrollable weather helm. The boat never goes fast enough (light winds) for the rudder to be able to counteract the rounding up moment of the sail (centre of effort too far back). When the wind is stronger things improve and with a jib it's absolutely fine.

That aside, with stuff-all wind and a sail as horribly shaped as the OP's, I'd take any wind-induced movement as a welcome surprise and be thankful for it. Wanting any form of directional control as well seems a bit greedy.

I know where you are coming from, but boats that don't sail half decently only put kids off sailing.
There are small boats that sail well for kids, it should not be beyond the wit of man?
The basic boats for small kids from topper/laser/RS are pretty basic, but do work pretty well.
If the sail cannot be persuaded to work, I'd advise a different sail or a different boat.
Some more photos showing the whole problem might help diagnosis.