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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 Topic: Wiki Sail by GRF
    Posted: 30 Mar 13 at 5:15pm
No no no, you're not slipping out from under it this time..

Answer the question.

Do you need some time to consort with your Frensham puddle friend?

Edited by iGRF - 30 Mar 13 at 5:16pm
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Post Options Post Options   Quote 2547 Quote  Post ReplyReply Direct Link To This Post Posted: 30 Mar 13 at 5:28pm
I fear you are confusing the navigational issues associated with making a course between to points fixed to the land and the actions of sailing a craft through the water. 
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Medway Maniac View Drop Down
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Post Options Post Options   Quote Medway Maniac Quote  Post ReplyReply Direct Link To This Post Posted: 30 Mar 13 at 5:36pm
Originally posted by iGRF

No no no, you're not slipping out from under it this time..

Answer the question.

Do you need some time to consort with your Frensham puddle friend?

Which part of "I don't think the true wind will react to my being at anchor or not" do you not understand?
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Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 30 Mar 13 at 5:42pm
No back pedalling from you either, stick to the point, in your own way, your little scenario exactly makes my point.

Which is, that it is the power of the true wind on your sails that is strengthened or weakened by tide action and if you think of it in any other way your passage and the apparent wind you can eventually generate to get you where you want to go, which, is over the ground and fixed points since we are discussing this in racing terms.

Where jimbo actually goes over the earths surface, is irrelevant to him in that instance since all he wants to do is plane and have fun, what for the most part we want is to get round a race course by the fastest, shortest or combination of both route.

Take my scenario, and reverse the tide, so both the wind and tide are exactly 4 knots from the north, then what happens?

Nothing, except you make 4 knots leeway once you lift anchor. How much apparent wind have you got then?

Edited by iGRF - 30 Mar 13 at 5:43pm
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Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 30 Mar 13 at 5:45pm
I can see I'm going to have to start with the wind and tide tactics lecture next.
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Post Options Post Options   Quote fab100 Quote  Post ReplyReply Direct Link To This Post Posted: 30 Mar 13 at 5:47pm
Oh for crying out loud

Please read carefully what James asked, the scallywag

Take the rig off the board. Stand someone who will not sink it on the board.  

Situation 1: There is 10 knots of wind blowing in exactly the same direction as a tide of 2 knots. Set aside windage and assume the board drifts at the same speed as the tide. How much wind will there be on a wind  gauge  used whilst on the board?

Situation 2: the tide turns, the true wind stays the same in direction and speed, but the board now drifts at 2 knots into the wind. What will the gauge say now?

Strangely, the difference will be 4 knots, which is rather significant in 10knots of true.

Put the rig back in. When will you go faster??



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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: 30 Mar 13 at 6:15pm
I'm not even going to answer that elementary tide for simpletons quiz.

The relevant point in James scenario is the difference between being on the plane or not.

The point I'm taking you and MM to task for is the suggestion that it is an apparent wind discussion which it is not and your pathetic attempts once more to suggest what I'm saying is in doubt with your normal bollox.

I'm sure you both think you know what you're talking about, but in using that reference to apparent wind, which has no bearing on the tidal effect until the craft is under way. The craft will or will not get underway depending on the tide and it's interaction with the True wind and anyone who suggests otherwise doesn't understand.

Your scenario can be simplified still further by standing on the beach and reading a wind meter (as often folks do when choosing sail size) then taking the same wind meter onto the water and reading it. Whatever the outcome that is the power available for you to use to sail with to then go on to generate apparent wind.

Fundamental discussion in any lectures on tide, obviously you haven't been to many.

Edited by iGRF - 30 Mar 13 at 6:16pm
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Post Options Post Options   Quote Bootscooter Quote  Post ReplyReply Direct Link To This Post Posted: 30 Mar 13 at 6:18pm
Originally posted by fab100

Oh for crying out loud
Please read carefully what James asked, the scallywag
Take the rig off the board. Stand someone who will not sink it on the board.  
Situation 1: There is 10 knots of wind blowing in exactly the same direction as a tide of 2 knots. Set aside windage and assume the board drifts at the same speed as the tide. How much wind will there be on a wind  gauge  used whilst on the board?
Situation 2: the tide turns, the true wind stays the same in direction and speed, but the board now drifts at 2 knots into the wind. What will the gauge say now?
Strangely, the difference will be 4 knots, which is rather significant in 10knots of true.
Put the rig back in. When will you go faster??


I get your point but that wasn't the question.
The question was about planing on one tack (going up-tide). If the board can do 10 kts say, across still water, it may be almost planing. When you add in that on one tack the water is traveling at 2 kts, for example, this will equate to the board travelling at 12 kts through the water, which could be enough to get it to plane (regardless of what the "GPS" speed is). On a reciprocal course, the board may well have a higher "GPS" speed, but may not be planing, due to a reduced flow of water under the board/hull. That's nothing to do with apparent wind, it's increased flow of water relative to the hull, in one direction.


Edited by Bootscooter - 30 Mar 13 at 6:21pm
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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: 30 Mar 13 at 6:33pm
Pointless arguing with them Bootscooter, it's been my experience down the years that there is an element that can reel off previously learned texts and scripts without fully understanding them, I used to see them all the time, either miles uptide having to foot off like crazy having over stood the mark, or miles down tide without a hope of ever making it..

As to your point, there's a buoy off the sailing club at Portishead, I swear if you lasso'd it you could waterski on the current there. There are times even with a fair breeze you can't go far enough up the coast to sail out and round it to come back again.

So your GPS point is well made, it could be perfectly feasible for james to be planing yet standing still over the actual ground.

Edited by iGRF - 30 Mar 13 at 6:34pm
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Post Options Post Options   Quote craiggo Quote  Post ReplyReply Direct Link To This Post Posted: 30 Mar 13 at 7:39pm
Graeme, your point about the bouy off Portishead is probably correct as the tide rushes around the headland at around 7-9kts. As for the other argument, I agree with your point about while the apparent wind might increase with wind against tide, the ability for the boat to plane is purely based on how fast the boat is moving through the water. Now you would hope that you could use the extra apparent to increase boat speed and therefore get planning, but it depends on the wind and tide vectors and the boats vector.

I'm off to slice my wrists now, as clearly some kind of mind trick has been played on me!!!!   
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