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These roll tack thingies..

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mozzy View Drop Down
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Post Options Post Options   Quote mozzy Quote  Post ReplyReply Direct Link To This Post Posted: 04 Dec 17 at 12:31pm
I get that hull shape can make a boat turn. But I don't feel it is more important than the where the rig is in relation to the hull. 

Also, don't all hulls flare in such a way that they head you up when heeled to leeward? In which case this would be another argument in favour of leeward heel on the entry. 

What sort of hull shape would require windward heel on the entry? And if that hull shape reacts well to windward heel when heading up on entry to a tack, why don't the sailors use windward heel when heading up in other situations, like the leeward mark? Or leeward heel at the windward mark? 

You don't see firefly (an example of a class which favours windward heel on entry) sailors heeling the boat to windward as they round up at the bottom mark, so why do it going in to a tack? 




Edited by mozzy - 04 Dec 17 at 12:35pm
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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: 04 Dec 17 at 1:29pm
Well given in the kind of light zephry type conditions I'm talking about there is very little 'pressure' from the rig and lets be honest the momentum both into and out of the tack is kinetic and this is the bit I'm doing wrong, being far to aggressive apparently but then that's as much about red mist with the damn top batten not transitioning..

So it obviously does matter where the rig is into the tack so should you leave it close hauled in and maximise the rocking momentum or should you sheet out a bit more than you normally might in order to maximise the inward sheeting combined with the roll back to weather?
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423zero View Drop Down
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Post Options Post Options   Quote 423zero Quote  Post ReplyReply Direct Link To This Post Posted: 04 Dec 17 at 1:29pm
I have a simpler interpretation, whichever way you heel it turns the other way, opposite to a bike.
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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: 04 Dec 17 at 1:45pm
Originally posted by 423zero

I have a simpler interpretation, whichever way you heel it turns the other way, opposite to a bike.

Exactly and why I like to heel the boat to leeward in these sort of conditions, this was another time in similar circumstance, so to go from there into a tack I obviously have to duck under the rig rather than the sensible way of walking round the front, but this inevitably initially rocks the boat the wrong way as my weight comes off the leeside.

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mozzy View Drop Down
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Post Options Post Options   Quote mozzy Quote  Post ReplyReply Direct Link To This Post Posted: 04 Dec 17 at 1:49pm
Originally posted by iGRF

that's as much about red mist with the damn top batten not transitioning..
Battens are a pain! In medium wind a pump of the main can be okay but the best option is a tug on the downhaul, especially in the light. If you have a crew, have them do this as you gently pull the boat flat. 

Originally posted by iGRF

So it obviously does matter where the rig is into the tack so should you leave it close hauled in and maximise the rocking momentum or should you sheet out a bit more than you normally might in order to maximise the inward sheeting combined with the roll back to weather?

In light winds you just have to be more patient. The forces all work the same way, you just have to wait for them to do their work. You're going slower through the water, so you're just going to have a slower rate of turn. 

Put (more) leeward heal on  squeeze on the main and be patient. Wait for the boat to round up then as the sail starts to stall slowly pull it on top (this will create apparent in the rig and keep teh sail driving through the tack). Hold the tiller loose and just let it follow the turn. 

Give plenty of ease on the exit and pull the boat up right very slowly. 

One thing you see a lot of people do in light winds is put a too aggressive pump in. You get the same amount of energy back (via increased apparent at the top) whether you pull the rig back upright quickly or slowly. But if you pull it too quickly you loose energy stalling the sail (detaching the flow), and the same happens for the foils below the water.  




Edited by mozzy - 04 Dec 17 at 2:05pm
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Tessa View Drop Down
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Post Options Post Options   Quote Tessa Quote  Post ReplyReply Direct Link To This Post Posted: 11 Dec 17 at 8:22am
Originally posted by mozzy

What sort of hull shape would require windward heel on the entry? 

Try comparing a Scorpion and an RS200. The big thing to deal with in a Scorpion is the hard chine on the hull. Windward heel on entry is less important than other things. However the right amount of leeward heel immediately reduces wetted area in a flat calm. In contrast in an RS200 it feels like the only thing we can do to unstick the boat from the water is to dig the bow in.

Tessa
 


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