What use is a kicker on loose footed mainsail?

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The Laser have a loose footed sail. Have a look at this thread to see how far off beam your analysis is.

[/ QUOTE ]It was this discussion that started me thinking about the differences between a small racing dinghy and a larger cruising boat. I kind of deliberately exagerated the 'analysis' to provoke a few responses. /forums/images/graemlins/shocked.gif
 
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Re-reading the OP, I read it as 'the kicker has no effect on a loose-footed sail'. I see now that it could also be read as 'when close-hauled the kicker has no effect'.


[/ QUOTE ] yes, this is what I was drying to say..... apols for 2nd response
 
I think the way most people sail, the kicker is loose when beating in fact that's when we generally tighten it. However, as I have what is effectively a fixed kicker, i.e. the boom height cannot be adjusted, I have had to look at how it works from first principles.

Let's say that when beating you have the boom end over the lee quarter. If you are overpowered and need to spill some wind, you ease the sheet and the boom rises. The head of the sail twists and spills wind from the upper leach. When heeled this can give weather helm.

The alternative is to pull the boom down with the kicker and use the sheet, with the traveller pulled to windward, purely to adjust the angle of the boom to the centre line. When you ease the sheet, the sail does not twist but retains its aerofoil shape.

I don't have an opportunity to compare the methods as I can use only the latter. I'd be interested to see how other boats react comparing both methods.
 
Ok.

So when beating in moderate conditions the kicker is slack, the twist is controlled with the sheet (and fine tune) and the angle of attack is controlled with the traveller. When a gust arrives the first stage is to let the traveller down to keep the boat on its feet.
When the traveller is all the way down and the boat is still overpowered the fine tune is eased at the same time as the boat is feathered up to windward. The kicker at this point is a little eased from "beating" and so the boom rises and induces twist, spilling wind. This DOES NOT induce weather helm, quite the reverse, not sure where you've got that one from!

If the boat is consistently overpowered in this setup the next step is to move the genoa car back, and match that twist with the main, but hopefully being able to move the traveller back up the track.

The next step is a sail change.
 
Don't forget that Snowy's got a variation on an aerorig. So the boom doesn't rise when the sheet's eased, just alters the angle of attack. Much like the mainsheet on my Merlin-Rocket. On that boat, the kicker was more like a hand throttle.
 
The kicker is used to help flatten the sail, so is of use in going upwind if you need to control/reduce the power of the sail. In the dinghies I have sailed its also used as a secondary mast bending device as the actiion of the kicker redirects the forces into the mast forcing it forward where the boom meets the mast, and bending the mast back above the hounds on a fractional rig. On a masthead rig you do not have this degree of additional mast control, so this aspect is less relevant.

In an upwind situation you need to decide whether you just need the kicker on enough to control the natural upward lift of the boom, in which case you do not need a lot of kicker in light/medium conditions, or whether you use it viciously applied as a true means of rig tuning in harder conditions.

Its horse for courses, but anyone not using a kicker imaginatively in some of the heavy conditions I have dinghy sailed in would have been in big trouble very quickly controlling an intentionally oversized main often found on racing dinghy design. The need to depower is often paramount and the kicker has its place in achieving this.

Tim
 
Wrong, the kicker has the same effect as with the foot in a track. I have a loose footed full battened main and the kicker flattens the main when required.
 
The kicker in addition to offering boom stability will act as a prevention/damper and safety feature against the boom lifting upwards resulting in total loss of control and damage to the main sail as it would in the event that the main sheet becomes detached, for instance in the event of an accidental gybe or any thing similar, whatever the point of sail. Am I on the wrong tack or are you simply refering to the performance charateristics of the kicker?
 
The halyard controls luff tension, and the clew controls the foot.

The kicker is there to control twist in the mains'l at whatever point of sail you choose, in conjunction with the mainsheet / traveller adjustment. Leach tension if you like, but it's twist that's the focus.



Sounds like you need a new boom
 
Unless in a boat with fractional rig and/ or bendy spars once you have applied enough kicker to remove the twist in the top part of the mainsail (when you want to)further tension can only stretch the leach which will not help the sail in retaining its good shape in later life.

Continued excessive downwards pull on the kicker or the mainsheet will eventually have your leach fluttering like a machine gun in a breeze. Tweaking the leach line will stop it fluttering but will curl the leach of the sail which should be flat.

The mainsheet track is often much underused on cruising boats by hauling it up you can bring the boom in without excessive downward pull on the sheet.
 
I can offer some recent practical experience. While sailing my national 12 dinghy (loose footed main) earlier this week in F3/F4 the shackle connecting my kicker to the boom came adrift and I was not able to reconnect it. To get back home I had to beat back upriver fighting with a boom that did not want to stay down.

Without the kicker going upwind was not very easy. In spite of hauling in the mainsheet as hard as possible (bending the mast) and with the boom pulled in on the centreline the top of the mainsail was twisting off horribly and I was not able to point very high.

As with the earlier comment on the Merlin Rocket dinghy I am constantly adjusting the kicker to optimise airflow over the main. Downwind or reaching I use much less kicker unless the wind is really howling.

I suspect that the kicker is an underused control in big boats.
 
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On a fixed foot sail the kicker keeps the boom from bending up in the middle, in fact tends to bend it down a bit thus keeping a flat foot.

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The mainsail on a fixed-foot main does NOT make the boom bend up in the middle. I've never seen it, never heard of it, and one look at a North 3DL sail will show you that there is no significant load at that part of the sail.

The main purpose of the vang is to control the vertical (i.e. up and down) position of the outboard end of the boom - to which the clew is attached. In layman's terms, it controls how hard you are pulling down on the clew (and leech) of the main. It makes no difference whatsoever whether the foot of the sail is attached to boom, or loose footed.

Of course the mainsheet can also do this when the end of the boom is within the limits of the traveller. One could say that the vang is a redundant control when close-hauled (on some boats), but not that it has no effect.

Quite simply, your hypotheses is wrong.

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bbg, you've got it. Switzerland, eh. Not related to Alinghi by any chance? Morally corrupt as a team but smart sailors nonetheless.

The rest of you are hilarious, you couldn't agree which way is up!
 
[/ QUOTE ] No mate, I just think you need to put more ice in it.

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After a little ice in with my Gin and some ice in the wifes coffee. In your case the answer to your question is safety.
 
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