Technical protest |
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fudheid ![]() Far too distracted from work ![]() ![]() Joined: 21 Apr 11 Location: 51.53 N 01.28 E Online Status: Offline Posts: 235 |
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That's too say, if this fence is creating any lift around it then it is a wing it contrivance under the definitions of the ERS/rule?
IF NOT. then how much wider/ bigger can it get before the lift it generates is a wing or contrivance? |
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Cheers you
only me from over the sea...... |
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fudheid ![]() Far too distracted from work ![]() ![]() Joined: 21 Apr 11 Location: 51.53 N 01.28 E Online Status: Offline Posts: 235 |
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Not attempting to make it a foil. If it reduces suction is that no creating lift? |
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Cheers you
only me from over the sea...... |
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423zero ![]() Really should get out more ![]() Joined: 08 Jan 15 Location: United Kingdom Online Status: Offline Posts: 2539 |
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Can't see it clearly on phone, but it looks like it also as a reduced chord ?
If the manufacturer designed blade purely to reduce suction and you attempt to make it into a foil ! Speaks for itself. |
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Robert
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fudheid ![]() Far too distracted from work ![]() ![]() Joined: 21 Apr 11 Location: 51.53 N 01.28 E Online Status: Offline Posts: 235 |
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So this fence isn't producing lift? It isn't shaped to change the flow of water around the foil? Canting / lifting the rudder doesn't increase our decrease the angle the fence makes?
Having a fence doesn't enhance the performance of the foil in certain conditions, i.e. it stops ventilation, stopping the stalling of the higher aspect foil? If I make this fence larger when does it become a non allowable wing? ![]() ![]() |
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Cheers you
only me from over the sea...... |
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423zero ![]() Really should get out more ![]() Joined: 08 Jan 15 Location: United Kingdom Online Status: Offline Posts: 2539 |
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Fence is not a performance enhancer, it is a fit and forget item, purely for maintaining steerage, much the same as a release cleat on rudder or a centre board that knocks back, plus a myriad of other boat damage limiting useful inventions.
Edited by 423zero - 19 Nov 19 at 4:25pm |
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Robert
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fudheid ![]() Far too distracted from work ![]() ![]() Joined: 21 Apr 11 Location: 51.53 N 01.28 E Online Status: Offline Posts: 235 |
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Ok so if it doesn't have anything to do with leeway or it isn't creating lift; what if the rudder is angled so the fence is at an angle to the flow of water does it creat lift then? so it must be one of these as it is a contrivance of somesort? Fences are not listed in the ERS so as a 'fence' it can be big as long as it is not producing lift (the national 12 rudder wing is not primarily about lift it is changing the flow of water off the stern - not lift?): (d) FIN
A fixed hull appendage primarily used to affect leeway or directional
control. (k) TRIM TAB
When a rudder(s) is used, a movable hull appendage, attached at the aft,
or fore edge of another hull appendage.
(l) WING A hull appendage attached to a keel, bilge keel, canting keel, fin or bulb, primarily used to affect leeway and/or lift. (m) FOIL A hull appendage attached to a centreboard, daggerboard, bilgeboard or rudder, primarily used to affect leeway and/or produce vertical lift. Edited by fudheid - 19 Nov 19 at 3:53pm |
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Cheers you
only me from over the sea...... |
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gbrspratt ![]() Posting king ![]() Joined: 26 Sep 11 Location: Felixstowe Online Status: Offline Posts: 169 |
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Is this not also true with a fence/wing/foil? Definitely looks like a duck.... |
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JimC ![]() Really should get out more ![]() ![]() Joined: 17 May 04 Location: United Kingdom Online Status: Offline Posts: 6358 |
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No, a fence has nothing to do with leeway or lift. Its purpose is to modify the boundary layer round the foil. The use on rudder blades is typically to attempt to reduce ventilation - sucking of air down from the surface - which causes the rudder foil to stall and the boat to lose control.
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fudheid ![]() Far too distracted from work ![]() ![]() Joined: 21 Apr 11 Location: 51.53 N 01.28 E Online Status: Offline Posts: 235 |
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is a fence not a similar contrivance? there's no mention of fences in the ERS. so a fence is a contrivance? as it primarily used to affect leeway and/or produce vertical lift?
Edited by fudheid - 19 Nov 19 at 1:31pm |
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Cheers you
only me from over the sea...... |
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423zero ![]() Really should get out more ![]() Joined: 08 Jan 15 Location: United Kingdom Online Status: Offline Posts: 2539 |
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Taken from latest rule book
C.8.2 Daggerboards, bilgeboards, double rudders, winged rudders and similar contrivances are prohibited |
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Robert
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