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Outhaul on a run -- tight or loose?

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Sam.Spoons View Drop Down
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 05 Oct 17 at 4:36pm
Bear in mind we are talking specifically about a dead run here.....

When skin friction is the major drag factor (i.e. in a drifter) plate up does reduce the wetted area quite considerably, as does sitting well forward and heeling to leeward to lift the aft planing sections of the hull clear.

Raking the board only changes the effective chord but I'm with you on up or down, the only time on Raceboards I'd rake was to control railing upwind in a blow. Boats are a bit different I think and, as speeds are usually lower, maybe the effect of rake on balance outweighs the other effects? I'll use half board on the Blaze off wind and lift the daggerboard on the Spice when overpowered to help keep the boat flat.


Edited by Sam.Spoons - 05 Oct 17 at 4:39pm
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iGRF View Drop Down
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Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 05 Oct 17 at 4:48pm
Well the logic for boards was dump it completely when windy as it gets in the way of planing, but if there isn't enough to plane, you kind of need it to pull against when you're, ahem, 'helping' the flow attach and re-attach to the sail.

But on say a Laser and I'd be the last person to ask, but surely if it's iffy and you're sailing downwind don't you need the resistance the plate gives to ensure the rig is performing if you have to sail an angle, I realise they sail by the lee a lot, but even then if it's marginal, don't they need some plate?


Edited by iGRF - 05 Oct 17 at 4:49pm
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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 05 Oct 17 at 6:13pm
Yup, not planing then board right down all the way round but we did indulge in what the dinghy bods would refer to as "unlimited kinetics".....  Wink

I think L@sers are impossible to sail without some plate, the Spice certainly is. Plus it if's up much more than halfway you can't gybe as it gets in the way of the kicker (then you capsize).


Edited by Sam.Spoons - 05 Oct 17 at 6:14pm
Spice 346 "Flat Broke"
Blaze 671 "supersonic soap dish"
Supernova 395 "dolly the sheep"
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Post Options Post Options   Quote mozzy Quote  Post ReplyReply Direct Link To This Post Posted: 05 Oct 17 at 6:18pm
It depends if you have a centreboard or daggerboard. Lifting a daggerboard does not change it's section so it's quite a viable option.  

In every boat with a daggerboard I've lifted it, but for different reasons. In toppers and laser I lift it on reaches and downwind, as you bear away the leeway reduces and you sit in. The leeway is equal to how much you're hiking. So the more you sit in, the higher the plate should be. Having it down just increases skin friction. However, you still need to keep a little down just to enable steerage.

In a skiff you're 'full' hiking pretty much around the course so you leave it down all the time to reduce leeway. 

You can also lift the plate to depower. Having too much plate in the breeze causes the boat to 'trip' up a bit when gusts hit. Plus, as you go faster you don't need as much plate to create the same lift. 

In the 200 with a centreboard, I agree with iGRF. Lifting it changes the section. It also moves the plate backwards in the boat which makes the helm feel funny. You also have to move it back quite far before you appreciably reduce the surface area. All of that has led to me leaving the centre board down in the 200. I know a few people lift it in the very light winds on the run. 


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Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 05 Oct 17 at 6:28pm
The shape of the hull also makes a difference, leaving the board down in an Ent on a run is a capsize waiting to happen if there's any wind. Half  board on reaches and fully up on runs was what I was taught. Of course it's hard to ruin the profile of an Ent foil more than it is by design  Wink

The Spice copes well with full board until you're getting overpowered so I generally set it for the wind strength and leave it unless it changes.
Spice 346 "Flat Broke"
Blaze 671 "supersonic soap dish"
Supernova 395 "dolly the sheep"
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By The Lee View Drop Down
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Post Options Post Options   Quote By The Lee Quote  Post ReplyReply Direct Link To This Post Posted: 05 Oct 17 at 8:00pm
To be fair that is one of the most common mistakes by club laser sailors that they lift the daggerboard to high on a run
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 05 Oct 17 at 9:23pm
Lifting a centreboard 2/3 up also increases longitudinal stability, which seems to stop the boat from broaching or rolling too much on the run. Firefly death rolls are scary things. Board up too much, and there is too little resistance to the roll, too vertical and the balance is all wrong and a broaching she will go. In very light winds, 3/4 up will be ok.
Firefly 2324, Lightning 130, Puffin 229, Leader, Topper 44496, yellow Minisail
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ColPrice2002 View Drop Down
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Post Options Post Options   Quote ColPrice2002 Quote  Post ReplyReply Direct Link To This Post Posted: 05 Oct 17 at 9:48pm
The other point is that raising a centreboard will shift the centre of lateral resistance.
To turn a dinghy downwind, raise the centreboard (pivot the blade backwards) and it's easy to turn downwind as well as acting more like a long keel design.

Just for Rupert - we used to reduce the Firefly death roll by having the crew sit out to leeward, helm to windward and not, emphatically not, to move body position. Ie don't try to keep body upright, roll with the boat. Also, don't try go correct the roll with the rudder! This increased to moment of inertia sufficiently to increase the period of the roll and make it less deadly. Techique was used with the old spoon rudder...
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Post Options Post Options   Quote 423zero Quote  Post ReplyReply Direct Link To This Post Posted: 06 Oct 17 at 7:51am
Sprint,
Beating, fully tight.
Reaching, adjust to suit conditions
Running, fully tight.
Centre board, short legs, leave it fully down.
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 06 Oct 17 at 9:59pm
Colprice, yes, moving is a deadly sin! Spreading by the weight sideways, but as close as possible fire and aft, pulling the mainsheet in and clenching ones buttocks also helps!
Firefly 2324, Lightning 130, Puffin 229, Leader, Topper 44496, yellow Minisail
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