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rb_stretch View Drop Down
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    Posted: 12 Oct 11 at 8:46pm
Originally posted by Peaky

 
That is the fallacy. The orientation of the boat's hull does not affect the direction it gets "pushed" by the current.


It depends on the angles. As soon as there is any component of the tide against the wind, you will get lifted. Basically means difference between tide and wind needs to be greater than 90 degrees and you will get some Lee Bow effect. At least in the definition I know.....
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 11 at 8:20pm
Originally posted by rb_stretch


Originally posted by seamonkey


This example is nothing to do with the lee bow effect .... which as JimC says is a fallacy ...


Clearly there are different definitions around as I've always used it and been around people who have used it to describe tide coming in on your lee bow and pushing you into the wind.

That is the fallacy. The orientation of the boat's hull does not affect the direction it gets "pushed" by the current.
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G.R.F. View Drop Down
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Posts: 4028 		Post Options Post Options   Quote G.R.F. Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 11 at 8:17pm
In the meanwhile I've had another look at Eric Twinames section on tide, he does deal with it, but he also misses the essential part of the tidal equation, which maybe back in those days wasn't as relevant and probably because the stuff we sail amplifies the effect (Literally a favourable tide in certain conditions can make the difference between planing up wind and displacement speed).

Wether you believe what I'm saying or not and lets face it the back end of the fleet is full of doubting thomases, it is a fact as sure as day follows night.

I'm available for lectures on tactical sailing in tidal situations...
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Posts: 6662 		Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 11 at 8:15pm
Originally posted by G.R.F.

It's not a fallacy, tide on your lee bow assists you, in some circumstances if the RO doesn't spot it, or it comes on during

Same term, different meanings... it sounds as if you've never come across the traditional lee bow fallacy.

That says that if the tide is more or less bang on the nose you should pinch up so that the tide is fractionally on the lee bow because even though you'll go more slowly the tide will push you up to windward.

Its nothing to do with the choice of which tack is favoured and thus which you should be on, which is what I believe you are talking about.
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Posts: 4028 		Post Options Post Options   Quote G.R.F. Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 11 at 8:09pm
No, go back to my scenario.

Taking the lee bow effect tack first, straight away, lets say the tide eases for the 2nd part of the beat.. = you're ahead you win.

Lets say it doesn't, it increases, they've gone too far = they over stand.

Tide is never ever constant.


Edited by G.R.F. - 12 Oct 11 at 8:11pm
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Posts: 1459 		Post Options Post Options   Quote sargesail Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 11 at 8:08pm
Exactly - not lee bow but a tidal consideration.
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Originally posted by G.R.F.

 
...... so those elements of the fleet that have taken the down tide tack first will be travelling faster over the bottom sideways, but slower through the water toward the weather mark than the boats that take the uptide tack initially, they move slower sideways over the bottom but make ground to weather and over the water faster, so at the half way mark are closer to their final destination.


At the half way mark you are closer to the final destination over the ground, but you are no nearer the mark through the water - the other guys get the tidal benefit when they tack as you start loosing out.

However...

Originally posted by G.R.F.

Originally posted by JimC

OK, GRF I think I see what you are talking about... To my mind that's an entirely different thing to the classic "lee bow/tide" fallacy. Am I right in thinking you're saying there's (often?) a tactical advantage to taking the tack that gets you nearest to the mark most quickly...

Eh? come on Jim, don't you be a chump.. It's not a fallacy, tide on your lee bow assists you, in some circumstances if the RO doesn't spot it, or it comes on during an event (say over lunch) you can single tack a beat and even then some idiots go the other way...



As above, it does make tactical sense, in the same way that it is (generally) better to take the long tack first on a very one sided beat, to insure against over standing the lay-line from a long way out.
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Posts: 4028 		Post Options Post Options   Quote G.R.F. Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 11 at 7:47pm
Originally posted by JimC

OK, GRF I think I see what you are talking about... To my mind that's an entirely different thing to the classic "lee bow/tide" fallacy. Am I right in thinking you're saying there's (often?) a tactical advantage to taking the tack that gets you nearest to the mark most quickly...

Eh? come on Jim, don't you be a chump.. It's not a fallacy, tide on your lee bow assists you, in some circumstances if the RO doesn't spot it, or it comes on during an event (say over lunch) you can single tack a beat and even then some idiots go the other way...

Tell me you'd go the right way now, i refuse to believe you don't 'get it'.

It's written large by Eric Twiname in start to win I'll wager..

I'm going to find that book and have a look.

I can't believe any of you are even doubting it.
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Posts: 1151 		Post Options Post Options   Quote 2547 Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 11 at 7:42pm
Originally posted by I luv Wight

But doesn't the RO notice the tidal current, and offset the windward mark?
if the course is square to the apparent wind then it dosn't make any difference.
 
The other examples you describe are just tactical tidal issues to manage.
 
Of course current is a key tactical issue but this thread is about the so called lee bow effect
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Posts: 742 		Post Options Post Options   Quote rb_stretch Quote  Post ReplyReply Direct Link To This Post Posted: 12 Oct 11 at 6:34pm
Originally posted by seamonkey



This example is nothing to do with the lee bow effect .... which as JimC says is a fallacy ...


Clearly there are different definitions around as I've always used it and been around people who have used it to describe tide coming in on your lee bow and pushing you into the wind.
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