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These roll tack thingies..

Printed From: Yachts and Yachting Online
Category: Keelboat classes
Forum Name: Technique
Forum Discription: 'How to' section for keelboat questions and answers
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=12925
Printed Date: 20 Jul 18 at 8:38pm
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Topic: These roll tack thingies..
Posted By: iGRF
Subject: These roll tack thingies..
Date Posted: 03 Dec 17 at 6:36pm
I'm advised as of today that 'you can tell I'm a windsurfer because of my crap roll tacks' not that I've ever formally assumed that this light wind technique I've fumbled into has ever been formerly taught or shown to me, but basically it's staying the wrong side of the boat (for the new tack) until it's gone round then using the leverage as the rig comes vertical and sheeting in at the same time to propel the boat forward on the new tack.

Now I know y'all can do this by rote and half my problem is sometimes wanting to grip the boom which you're not supposed to, but it helps feel 'pressure'. I am apparently sheeting in too hard rather than I presume sheeting the rig vertical then rolling the boat to the new side.

I can't even remember what it is a I do do, but I'm sure there must be little rid bits of intel here should think about in lining up for them, this is virtual drifter wind was on and off today and I'm never much good when there's virtually nothing to work with wind wise.

If you could point me at any videos you've seen might help, bear in mind this Solution is quite a wide bodied affair and it's a fair distance from one side to the other compared with a Laser, not quite as bad as a Blaze, but still far enough.

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Replies:
Posted By: 423zero
Date Posted: 03 Dec 17 at 8:08pm
I learnt roll tacking from rudderless sailing, but very rarely use it, mainly because of catcalls at my club about "propelling".
Stupid question, sorry, do you know why boat turns when heeled ?


Posted By: Rupert
Date Posted: 03 Dec 17 at 8:34pm
The hull shape becomes asymmetric.

There is nothing illegal about roll tacks. It is against the rules to come out faster than you go into the tack, due to your actions, but given how much a boat slows going through the wind bringing it back up to speed quickly is a must.

As for tips, one thing to remember is to release the main a little in the tack. When you pull the boat upright, you are, for a brief moment, on a beam reach, as the mast pulls upright. Sheet in as you bring her up and get back on course. Steve Cockerel and the Boat Whisperer DVDs show it well, and get specific Solution training on the long walk across!

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Firefly 2324, Lightning 130, Puffin 229, Topper 44496, Minisail 3131, Minisail 3446


Posted By: ColPrice2002
Date Posted: 03 Dec 17 at 10:13pm
There are two types of roll tacking:-
1) let the dinghy heel to leeward to initiate the tack, using the hull shape to make the boat luff into the wind. As the boat passes head to wind, keep the heel until on new close hauled course, then flatten the boat.
Ease the mainsail so that flattening the boat gives more drive before sheeting in again.
This method uses virtually no rudder, so there's no brakes applied.

2) As I learnt in Fireflies, Enterprises and Solos
To tack, heel the boat to windward lots, easing the mainsheet and a bit of helm to luff. Once the boom has passed overhead, stand up, cross the dinghy, settle on new close hauled course and sit out.
This method doesn't use the hull shape to steer, by heeling, you're making the bilge of the dinghy immersed, this drag is off-centre so the hull turns, and the length of the hull immersed is much shorter than the keel length so the boat turns faster.

Which method you use depend on your dinghy's hull shape:- method 1 is the basic RYA roll tack and works with most dinghies and also rudderless; method 2 works for me in the classes I mentioned (round bilge hulls).
(You're not doing it properly unless you scoop water over the gunwhale!)

Colin
Edited to spell my name properly😕


Posted By: Rupert
Date Posted: 04 Dec 17 at 8:26am
Just noticed this is in the keelboat section, which makes things harder. Can remember too tacking a Sonata up the Dart in the 80s. Surprisingly effective.

As for the 2 types, I guess I grew up in Fireflies, and have just seen type 1 as a slowed down version of type 2 for less nimble boats.

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Firefly 2324, Lightning 130, Puffin 229, Topper 44496, Minisail 3131, Minisail 3446


Posted By: mozzy
Date Posted: 04 Dec 17 at 9:18am
I've always viewed the windward heel on entry as poor technique, whatever class. The pump flat looks and feels impressive, but only because the boat has lost so much speed on the entry. 

I'm not convinced it is hull shape is the main factor which is turning the boat with heel, but the CoE of the rig moving out over the side of the boat.  

I've always sheeted on for entry, to close the leech, put a little leeward heel on to make the boat screw up to wind quickly. You then pull the boat through upright. This gives you a propulsion when heading directly in to the wind. Every inch you can make whilst head to wind is worth double. You then ease the sheet as you cross to let the flow re-attach as pull the boat flat on the new tack. 

Done well the entry should look and feel like 'shooting a mark'.  Legally you're not allowed to gain speed through a tack, but you can gain ground by taking a big a grab of water as possible. 

Once it gets windy enough that you're easing main upwind I don't role tack, just put a little leeward heel on for the entry and ease the main nicely on the exit. 

I wouldn't know how to role tack a yacht. 

Flick through to 1:27. Sheet on and leeward heel on entry. Pull through on top as you cross wind. ease main and pull flat on exit (ignore the last tack, was looking to duck another boat on the exit). 
[TUBE]2MkCECKhDU8[/TUBE]






Posted By: JimC
Date Posted: 04 Dec 17 at 9:53am
Originally posted by mozzy

I'm not convinced it is hull shape is the main factor which is turning the boat with heel,

depends on the boat, some hull steer enormously, others much less so.


Posted By: mozzy
Date Posted: 04 Dec 17 at 10:48am
Here's another video... good exercise to practice tacks too. Some of the tacks are okay, some not great. 

[TUBE]v=gRkpRA0t8aY[/TUBE]

I'll remain sceptical that different hull shapes being the main driver in dinghies turning with heel until someone can show some good evidence. 


Posted By: iGRF
Date Posted: 04 Dec 17 at 12:15pm
I know about footsteering things without rudders and get immense grief down the lake everytime I stand up to get the damn thing to heel to leeward at the end of a little puff. Also downwind they don't like me stood up making 'corrections' using my weight rather than the rudder. It's natural to me, you can't eradicate forty years of footsteering and these sitty down things need a lot more pressure to make them do what you want.

They work like boards as you would 'flare' rather than 'carve' gybe the difference being turning with the plate down or up which requires pressure on the opposite side to the other. i.e. windward side with the plate down, leewood side if the plate is up, so I get all that.

The bit I can never fully get is the amount of leverage to apply on the sail via rope and always end up reverting to holding the boom to get the right feel, but, 'they' don't like me doing that much either and I'm constantly watched like a hawk for 'illegal' moves.

Now 'they' are a particularly good couple of females who sail rings round me in their Miracle in any wind and they seem to have a better 'feel' obviously born of experience and ability to trim their rigs conventionally in iffy wind. What with them and a the bloody green ghosting solo my sunday morning has once more been ruined just as I thought I'd returned the natural order of things to the universe with an earlier win.

Oh and thanks for all your help I've read it all and some of it does occasionally sink in..

and apologies for putting it in the wrong section, not on it at the moment, think it's early onset man flue..

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Posted By: iGRF
Date Posted: 04 Dec 17 at 12:22pm
Originally posted by JimC

Originally posted by mozzy

I'm not convinced it is hull shape is the main factor which is turning the boat with heel,

depends on the boat, some hull steer enormously, others much less so.


This is true, a lot depends on the stern shape, an RS200 must be a bloody nightmare...

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Posted By: mozzy
Date 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? 




Posted By: iGRF
Date 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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Posted By: 423zero
Date 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.


Posted By: iGRF
Date 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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Posted By: mozzy
Date 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.  




Posted By: Tessa
Date 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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