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Lee-Bow..... Windsurfers...etc (Dons tin hat)
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Sam.Spoons View Drop Down
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Posts: 3401 		Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Topic: Lee-Bow..... Windsurfers...etc (Dons tin hat)
    Posted: 24 Sep 19 at 8:26am
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 19 at 12:44am
If no one else takes up the challenge of drawing the free body diagram by the weekend, I will. No spoilers on the outcome!
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Posts: 8956 		Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 23 Sep 19 at 10:04pm
Originally posted by L123456

Sigh ... it’s simple vector maths ...


Can you draw it for us stupids then please?
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Posts: 500 		Post Options Post Options   Quote L123456 Quote  Post ReplyReply Direct Link To This Post Posted: 23 Sep 19 at 8:10pm
Sigh ... it’s simple vector maths ...
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Posts: 13 		Post Options Post Options   Quote yottiemad Quote  Post ReplyReply Direct Link To This Post Posted: 23 Sep 19 at 7:58pm
In the middle of a fleet upwind at a sea event you are likely to have peeps who mainly sail inland and pinch all the time and given the correct tide direction think they are a genius as they are pointing 5 degrees higher than those around them and then end up very slow when they hit a passing motor boats wake, then you have the low and fast guys always in footing mode looking for the first header to max the gain when they tack. the guys who win probably do both and change modes as the steep chop hits. It would be hard for a book,maths or reason to be able to teach what some do as instinct. It helps to do many events per year in good fast company in tidal conditions.
something lacking in my sailing in recent years. Ouch
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Posts: 3420 		Post Options Post Options   Quote 423zero Quote  Post ReplyReply Direct Link To This Post Posted: 23 Sep 19 at 7:03pm
I find it difficult to envisage a vessel in middle of a pack getting a lift from current, but not others around ?
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Posts: 6499 		Post Options Post Options   Quote iGRF Quote  Post ReplyReply Direct Link To This Post Posted: 23 Sep 19 at 6:19pm
Originally posted by GarethT



Could there ever be any circumstances in which the resultant forces due to the rig are equivalent to the forces on the ferry due to the rope?


Obviously there are, and the principle behind the 'effect' they are all trying so hard to deny.

Honestly, it's not worth arguing with them, they are not all there and either can't or won't ever get it.
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Posts: 6662 		Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 23 Sep 19 at 9:48am
Only really comparable if its a crosswind and the boat is reaching I think.
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Posts: 714 		Post Options Post Options   Quote GarethT Quote  Post ReplyReply Direct Link To This Post Posted: 23 Sep 19 at 8:58am
I’m not going to do the maths to resolve the instantaneous forces, but just wondering ......

Could there ever be any circumstances in which the resultant forces due to the rig are equivalent to the forces on the ferry due to the rope?
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Posts: 552 		Post Options Post Options   Quote SoggyBadger Quote  Post ReplyReply Direct Link To This Post Posted: 22 Sep 19 at 9:31pm
Originally posted by PeterG

 It's a misuse of the phenomenon used in olden times where a ferry was connected to a rope stretched across the river and would be pushed from one bank to the other by action of the boat held at an angle to the current.

I thought "ferry glide" applied to self powered ferries not on a rope - where crossing a current you need to point into it to some extent to get the correct net vector across.



I've seen/heard it used a lot in canoeing/kayaking circles. As you correctly say it's just a matter of pointing the vessel in the right direction - simple vector maths. But some people seem to believe that there's something special happening, which there isn't, and that's really why I flagged it up.
Best wishes from deep in the woods

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