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Old 17-02-2011, 21:04   #31
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A boat does not feel the Earth, only the water it floats in and the wind that pushes it. Any speeds or other measurements with respect to the Earth are irrelevant to what you might feel through the helm.
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Old 17-02-2011, 21:09   #32
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The wind doesn't know what the water is doing
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Old 17-02-2011, 21:17   #33
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If i sit in a coracle and the TWS = 10kts, the AWS = 10kts

If the current pushes me toward the wind at 2 kts, the AWS = 12kts

If the current pushes me away from the wind at 2 kts, the AWS = 8kts

There is a big difference between sailing in 8kts and 12kts
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Old 17-02-2011, 22:04   #34
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Well,I asked one of my friends..Google
That Damn Tide - SailNet Community
Current and tide
you'll have to skim down to pertinent but it's there.

there's more of course:windsurfers,good explanations of weather helm+ apparent wind +current and now WE are all there, on google, too...
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Old 18-02-2011, 02:48   #35
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A boat does not feel the Earth, only the water it floats in and the wind that pushes it. Any speeds or other measurements with respect to the Earth are irrelevant to what you might feel through the helm.

oooo ..nice edit

But the current is hardly irrelevant in a discussion on the effect of current I feel, and how else would you measure current if not in respect to the earth?

What you measure (whether in relation to the earth or apparent to the boat) is irrelevant, but what is actually happening with the wind relative to the earth (TWS, TWD), water relative to the earth (Current speed & set), the direction of the boat relative to the earth (COG) and the speed of the boat relative to the earth (SOG) is all very relavant to what goes on when sailing.

But I agree - none of this causes excessive weather helm.

That's caused by poor trim, poor boat build / set up and another reason (that I dare not mention in the presence of esteemed company we are keeping on this thread )
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Old 18-02-2011, 06:37   #36
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Gull:
Weather helm issues are almost always due to keel/mast placement relationship. Other issues like sail shape and choice and mast rake can come into play but generally it mast/keel retionship that is at the heart of helm issues.
And yet excess helm is not an uncommon complaint among sailors about their boats, especially when the wind pipes up. Sailing and sailboat design has such a long history, shouldn't designing where the mast/keel placement should be in order to have a good helm for any given design be a relatively easy thing to determine now a days?

If not, what are the obstacles that designers have that could potentially have them design a boat that has more weatherhelm in real life than they thought it would when they initially drew up the design?
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Old 18-02-2011, 07:53   #37
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Years ago I drew some boats that had more weather helm than I liked. Note the bowsprit that was added to the Valiant 40. In time I made adjustments and for years now my boats have been well balanced. Sometimes there are pragmatic issues that define mast location, i.e. interior layout requiremnents and there is always the effect of ballast weight location on where the keel goes and it's not always where you want it. Boats with big, fat fannies probably want the keel to be forward to keep the boat in trim. But when these boats heel over they show very assymentrical waterlines and the keeel wants to move aft. You can't always win. I always do my best to keep my designs as narrow as reasonably poosible. Narrow boats are far easier to balance. After 5,000 boats you begin to develope a feel for it.
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Old 18-02-2011, 09:31   #38
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A boat does not feel the Earth, only the water it floats in and the wind that pushes it. Any speeds or other measurements with respect to the Earth are irrelevant to what you might feel through the helm.
What? That's crazy.Wind is air motion,relative to the surface of the earth.As is Current.Weather helm is rudder feedback as a force.You can name it,measure it as foot lbs,and so on.Nothing can be measured without being related.The fact that the whole planet,air,water,sailboat included is spinning and in motion at 25000 mph (at the equator) relative to the earth's axis is all very interesting but since they all are,it's meaningless.And further,a wind there blowing east at 2o has speed 24,980 mph.
The wind and weather helm can be calculated galactically..it still boils down to the same force however described as a relationship.
As to what the boat feels -she "feels"various wrenching forces imparted by other forces.That's all anything feels.or is moved by,destroyed by-Forces relative one to another other.with matter as the transmitter.The medium.

...imagine a dandelion side floating in the air...it feels no "wind".It "sees" the ground go by-some here seem to suggest that it's the only way it could know,by observing the ground......tralala.But (for the sake of simplicity),suddenly it drifts into an updraft -a current-up she goes!Does it know?
(pause)
The answer is Yes,acceleration!like an elevator.All measureable relative to something.And I am ignoring the moment it was torn from the dandelion crown and changes in acceleration before the updraft.The dandelion fluff may even be minutely compressed and change height ALL measureable.ALL relatable to the earth,the grass,the sun, the big bang.But not changing the fact whatever.
A "change" in helm might be seen as an "acceleration" in a distant confusingI bet way
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Old 18-02-2011, 10:07   #39
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I thought this was a sailing forum.
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Old 18-02-2011, 10:28   #40
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It might be beneficial to ignore the advice of the experts for the moment, and try the experiment I proposed. It will cost you nothing.

Again, take your boat out on a windless day, and situate it beam-on to the current. Cease all forward motion of the boat, allowing it to drift. Note whether the boat consistently turns bow-down or stern-down to the current while drifting.

If the boat tends to remain beam-on to the current, then the problem is either with your rig or the sail trim. If the boat tends to round up or round down in the current, you've determined that the problem is in the design of the hull-keel-rudder configuration of the boat.
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Old 18-02-2011, 10:33   #41
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Again, take your boat out on a windless day.....
No apparent wind? No boat-true wind? Or no earth-true wind? We need to know.
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Old 18-02-2011, 11:59   #42
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It might be beneficial to ignore the advice of the experts for the moment, and try the experiment I proposed. It will cost you nothing.

Again, take your boat out on a windless day, and situate it beam-on to the current. Cease all forward motion of the boat, allowing it to drift. Note whether the boat consistently turns bow-down or stern-down to the current while drifting.

If the boat tends to remain beam-on to the current, then the problem is either with your rig or the sail trim. If the boat tends to round up or round down in the current, you've determined that the problem is in the design of the hull-keel-rudder configuration of the boat.
I am not sure what you are getting at.
The sail is up.How much current?In ONLY 2.5 nots apparent wind it's unlikely that the sails would do much of anything except slat gently due to their mass (inertia)being too large for the forces involved.I'd be in Bobperry's camp for this one.. and I don't get what the hull means per weather helm in this instance given I am correct.It would not matterwhat you had down there.

I wonder if you mean?:as in apparent wind=0.
I mean, drifting sideways where wind is same as current in speed and direction.In this case,again,but simpler,you could have any underwater configuration and nothing would happen until you wandered into an eddy or a wave .You could place the boat sideways,or ANY aspect and it signifies nothing.It's all the same.
"Helm" is feedback.There would be none HERE (wind=current)without a swell,or eddie or some outside extra imparting some mass acceleration.
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Old 18-02-2011, 12:02   #43
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I thought this was a sailing forum.
Dandelion seeds have "sails".

and weighted "keels" too.
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Old 18-02-2011, 12:18   #44
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Pay attention, youngsters. If a current abeam pushes unevenly against the boat's hull/keel/rudder, causing the boat to pivot, then helm will need to be applied to correct for this once moving forward. That amount of helm, which would add to weather helm on one tack and subtract from it on the other, could make the rig appear to be out of trim.

I'm not saying that this is necessarily the case in the OP's situation. I'm merely suggesting that it would be easy to test for this on a windless day.
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Old 18-02-2011, 12:19   #45
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Exactly, you prove my point. This is supposed to be about sailing not angels dancing on the head of a pin.

You need to get out on a boat. do some racing , get in touch with the reality of sailing. If you donlt race you are a hacker. Racing is where you learn the nuances/reality of what makes a boat go.

Or, you can sit in your garden blowing dandelions.
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