What does the kicker do?

Hi all,

The CA have a nice article about it all:

http://www.rs600.org/docs/RS600/tuning/RS600TuningGuide.pdf

Hi Peter,

This is a massive subject, so what I'd suggest you do first is to rig your boat, turn it on it's side (on a flat area) and prop the top of the mast up on a chair or something so it is horizontal.
Then get some very lightweight plastic balls (like those in a ball-pit for kids) and put them on the sail (with the boom sheeted all the way in.

What you can do now is play with the outhaul, Cunningham and kicker and see exactly what happens to the deepest part of the sail for yourself.
Others will be along shortly to go in to far greater depth, but in very (VERY) simplistic terms you want to work out what makes;
A) a flat(ish) sail
B) a full (or deep) sail

In very light winds you want a flat(ish) sail so that the air flowing over it doesn't have a massive change in direction to make.
In medium wind you want more power, and this comes from having a fuller sail.
In strong winds you need to de-power, and you do this by flattening the sail.

You will get a flatter sail by tightening the 3 sail shape controllers, and they all work together, so pulling on one will need you to adjust the others also.

For example, with the balls in place on your sail, pull on the kicker.... the sail will flatten a bit, the leach of the sail will lift and the deepest part of the sail will move aft. This movement aft is not really a good thing as it will induce weather helm (the boat feeling like it wants to turn in to wind).
Without adjusting the kicker from this hard-on (fnarr!!) position, now also pull on the Cunningham (downhaul). You'll see the balls roll forward on the sail as the deepest part moves back to a position close to being in line with the daggerboard.

This is all very simplistic, but will give you a good visual clue as to what's going with your controls.... the rest is going to be about reading up then playing to see what works for you.

Massive apologies if this comes across as an egg-sucking lesson - not meant that way at all.

Confusing isn't it.  

RS600 doesn't have lowers and in comparison to the 700 has a very stiff mast. As a result the primary use of the kicker is to hold power in the main by stopping the leech from opening. For light winds the kicker needs to be eased and leech tension held only with the mainsheet. This is because the kicker as well as tightening the leech also bends the mast and as a result the effect of the two is for the upper leech to 'hook' to windward. This stalls the top of the sail losing vital power. On the 600 as soon as you have enough breeze to either hike off the racks or trapeze you will need to be winding on the kicker to hold the leech as letting it fall away will allow it to feather into wind and give you no drive. It's this point at which pulling on kicker in a 600 feels like a power switch. If you are hiking when you pull on the kicker the boost in power will see you leaping out onto the wire. If you are already on the wire, then you'll need to ease a bit of sheet or pinch as you squeeze the kicker on.
Progressively as it gets windier you will need to pull more on. On the 600 when you hoist the main with kicker fully off it should go pretty taught with the main fully up. In a F3-5 you will need to pull kicker on block to block (really, pull it until the floating block in the cascade hits the bottom block) upwind. For reaches it only needs minimal easing but will need to be fully eased down the run. When it gets super windy, you will not be able to hook the main due to the load, so you are looking to twist the top into wind. This may require a slight ease of the kicker, with a lot of cunningham.

Edited by craiggo - 13 May 14 at 11:18pm