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Mainsheet Systems

Postby Dave Bacon on Mon Mar 17, 2008 12:03 pm

Late last year I purchased a new Sabre. I was persuaded to purchase a stand up extension about 200mm long for the mainsheet block, as “everyone is using it.”
In my copy of the construction and fitting out notes, the mainsheet system is described as running through a floor-attached block to the skipper, so ‘via an extension’ conforms.
The latest modification, as seen at the Nationals on Tasmanian boats, is to fit diagonal bracing from the thwart to the extension. This would appear to offer some advantage in slightly improving the angle of the mainsheet lead, and removing the irritating movement of the mainsheet block during minor trimming. The block is attached to the thwart as well as to the floor. This has since been ruled as legal and has been adopted by a few guys in the Victorian Fruit Fly area
How far can we go along this path? The length of the extension is not measured. Doubling the length of the extension further improves the angle of the mainsheet lead, but this is probably of little overall effect with the balance of the sheeting purchases being led off the strop
However, if the length of the extension is increased so that the block is almost level with the boom, the angle is greatly improved. This could allow the removal of a least one block on the boom, making for faster trimming for the same effort. It would also be useful as a grab handle for the hairy downwind legs. If I remember correctly from my time in Fireballs, in those days it was known as the ‘Loveday Loop’ or the ‘Geriatrics Tacking Aid’
A further improvement could be made by allowing the extension to pivot at floor level and fitting an overcentre lock mechanism or, as I recently saw on a Javelin, control lines so that the pull is to windward of the centreline.
I suggest that any of these systems would be ruled as legal under the present interpretation, but before I get into detail design and fabrication I would welcome any suggestions from anyone with relevant experience as applied to a Sabre.
Cheers
Dave
P.S. No problem with extra weight – I’ve got 1kg on the transom.
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Postby CDance on Mon Mar 17, 2008 2:29 pm

Hi David,

Before doing anything "out of the norm", I'd suggest you consider:

Sabre Class Rule 1.10 - e.g. if it's not explicitly allowed, then it's a NO
Sabre Class Rule 1.1 "Any type of solid or wire mainsheet track;" - this would preclude any "loveday loop" arrangement.

I agreed that rule 5.2 is a little open ended and not really clearly worded. For example:
* Does the leading noun, "Method" refer to the method of obtaining the purchase, the method of attachment(s), or all of the above?
* Is "slack rope hawse" intended to duplicate the prohibition in 1.11? Or is it there to tell us that we should not pull it tight? What is the definition of slack?
* Is "floor attached block to the skipper" intended to override RRS42. If so, as per rule RRS86, should it not explicitly state this?
* "Where rope hawse is used" in the 2nd paragraph seems to imply that it's optional, while the proceeding sentence uses the word "must"? Which one takes precedence?
* There is an obscure exempli gratia reference in 1.12 that uses language not used elsewhere in the rules. What's going on here?

Anyway, I can't be too critical as I know the measuring committee have been secretly working on a new set of rules and these were adopted without discussion at the national AGM this year. The "public" is yet to see these changes, but I'm sure they have cleaned up these ambiguities, and this, in conjunction with the addition of Mylar sails, will be warmly welcomed by all Sabre sailors :-)

If you're about to try something different, it might be worth requesting an interpretation before outlaying any time/money.

Cheers,

Chris

Numbers above reference the "latest" class rules posted on the association website at: http://www.sabre.org.au/documents/SABRE ... 300607.pdf

PS: I question if the diagonal brace, or longer extension offers any "improvement to the angle of the mainsheet lead". Is the brace just there to stop the block from falling over? I'm sure you'd find others that would argue that a shorter strop is better as it increases the wrap angle around the ratchet block. The other classes you referred to (Fireball and Javelin) have Jibs and hence tend to benefit from centered sheeted booms. The same is not true for the single sailed Sabre.
Last edited by CDance on Mon Mar 17, 2008 3:24 pm, edited 1 time in total.
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Postby Mike Simpson on Mon Mar 17, 2008 2:45 pm

I believe these fittings are clearly in contravention of TWO rules; 1.11.2(k) which prohibits struts between the thwart and the floor and 1.11.3(n) which requires that the mainsheet shall lead from a block on the keel stiffening timber to the hand.

Another item seemingly prohibited by inference are "enhanced" compasses such as the TickTack, which has memory and computing capability, and is outside the stated concept of the Sabre as "a sailing dinghy that is simple in design and construction and relatively easy and inexpensive to build."

Incidentally, if anyone feels like testing the legal limits of the mainsheet system, I have a "Loveday Loop" left over from one of our Fireballs and would make it available for a small fee.

Fair winds and fair sailing
Mike Simpson
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Postby CDance on Mon Mar 17, 2008 3:16 pm

Hi Mike,

I can't find any references to rules 1.11.2(k) and 1.11.3(n) in the "Complete Sabre Measurements in PDF (as at 30/6/07)" available on the associated website at as of the 17th of March, 2008:

http://www.sabre.org.au/rules_measurement.html

Maybe we have all been racing under the wrong set of out-dated rules? :-)

Also can you qualify the statement "seemingly prohibited by inference"? Is this a personal opinion, or an official interpretation in line with the procedure followed by other classes ( http://www.sailing.org/10619.php )?
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Postby Mike Simpson on Mon Mar 17, 2008 5:24 pm

The newly adopted rules have not yet been posted to replace the old ones.

Some of the "new" rules have been moved from the building guide and fitting out instructions to within the rules proper - this has been a consolidation and do not involve any major change from the previous requirements. I'll remind Ashley about getting them updated on the site!

My comments on this subject are my personal opinion - I am not empowered to make official interpretations. These must be made by the National Measurer or the National Committee (which does not presently exist) or at a General Meeting (Special or Annual).

I have some problem understanding how RRS42 may be overridden by Rule 5.2 (still current) - explain please.

I am keen that issues like these be discussed in this forum.
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Postby Dave Bacon on Mon Mar 17, 2008 6:13 pm

How can a fitting purchased from a measurer be illegal??
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Postby Dave Bacon on Mon Mar 17, 2008 7:42 pm

[quote="CDance"]Sabre Class Rule 1.1 "Any type of solid or wire mainsheet track;" - this would preclude any "loveday loop" arrangement.

Chris,
The National Measurer has already approved of the post braced off he thwart for mounting the mainsheet block. A loveday loop is just a longer post similarly braced and could in no way be considered as any form of track.
Dave
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Postby CDance on Tue Mar 18, 2008 11:47 am

Mike Simpson wrote:I have some problem understanding how RRS42 may be overridden by Rule 5.2 (still current) - explain please.


RRS86 allows class rules to modify/change RRS42. Some examples of this in classes similar to the Sabre (e.g. single-handed, one-design dinghies) are:

    Finn: They have a "do what you like" (a.k.a. air rowing) rule when code flag O is displayed. [1]

    OK Dinghy: At the other end of the scale, the OK Dinghy class rules tell you how to hold the mainsheet - that is, only from the block off the floor (e.g. no pumping directly off the boom). [2]

I agree that it's a stretch, but I can see how one could argue that language like:

1.12 "Mainsheet shall lead through a block on the keel stiffening timber to the hand;"

and

5.2 "Run between slack rope hawse on thwart, to the boom, then to floor attached block to skipper"

could be interpreted that, like the OK Dinghy, the rules are telling us how to hold our mainsheets! Would pumping directly off the boom mean that your mainsheet is not running from the floor block "to the hand" and hence is being used illegally? Do we need to sail our boats like the OKs? I'm sure this is not what is intended as this Sabre class rule was probably written well before class rules where allowed to change RRS42. It is however worth considering this ambiguity when the rules are next redrafted. In my opinion the rules should focus on the equipment/system rather than things like "hands" or "skippers".

Mike Simpson wrote:I'll remind Ashley about getting them updated on the site!


That's great and was the objective of my post. It's important that we're all racing under the same rules, and all members have access to the same information.


Mike Simpson wrote:My comments on this subject are my personal opinion - I am not empowered to make official interpretations


That may be so, but if I'd recently outlaid a lot of money for a fancy digital compass (as a few sailors have done), I'd be a little concerned with a statement like this coming from someone who has recently been involved in redrafting the rules. It will be interesting to see how this one plays out.

Cheers,
Chris

References:
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mainsheet extension

Postby GuestMember on Wed Mar 26, 2008 8:54 am

Hi Dave

Wow, you have started some discussion!
As the person in Tassie who first built one of these for a sabre I should explain my thinking.
Keeping the extension rigid was a way of improving the run of the mainsheet through the ratchet. With a moving extension every time it is eased the block swings across in an arc for quite a few inches before the ratchet disengages.
That's all it does.
I checked with the measurer and the interpretation i recieved is okay so long as it doesn't strengthen the boat.
Your idea of increasing the length probably won't work on the Sabre, being cat rigged.
Loveday loops work on sloops, as the jib slot allows the main to be trimmed into the centre-line. Do this on a Sabre and you will kill it upwind.
As a comment on the rules it would be good to have the measurers interpretations, as they are made, added to the rules to help clarify things for the sailors.

Cheers
matt
1747
Alchemy
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Re: mainsheet extension

Postby CDance on Thu Mar 27, 2008 3:58 pm

GuestMember wrote:... As a comment on the rules it would be good to have the measurers interpretations, as they are made, added to the rules to help clarify things for the sailors.


Changing the class rules every time a question comes up would probably be too much work. The "best practice" is to revise the rules every X years, and issue interpretations on "gray areas" that arise between revisions. The interpretations are then considered when the rules are next redrafted. You can see this process in action for the international classes here:

http://www.sailing.org/10619.php

It's very important that interpretations are in writing and published to all members - otherwise they're just hearsay. ISAF produce a lot of guides and manuals to compliment the RRS (e.g. Sailing Instruction Guideline, and the Race Administration Manual), and the same is true for class measurement procedures/policy. Here are a few links:

Measurer's Manual: http://www.sailing.org/20487.php

Standard Class Rules: http://www.sailing.org/21094.php

Class Admin: http://www.sailing.org/2091.php

It would be interesting to see all recent Sabre class interpretations such as the one we have been talking about here. Where do we find these? Any chance of having them on the website?

Cheers,

Chris
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Extension 'pole'

Postby andrewb on Thu Jul 10, 2008 1:53 pm

Sorry to have to open this old topic again, but I now have to fix a broken mainsheet fitting on the floor after the regatta at Albert Park (not my boat - the better 1/2's!).

The stainless-steel swivel on the keel has broken - due to the leaverage applied by the 'extension pole' fitted to raise the height of the ratchet block. I see in this thread that some boats have been fitted with bracing to the extension. By my reading of the latest rules (downloaded from the website 10/7/08) both the extension and thus any bracing are illegal:

Rule 1.11.3 (Options states:
n. Alternative types of control systems (provided maximum purchase limits are not exceeded and
other requirements are met, e.g. mainsheet shall lead through a block on the keel stiffening timber
to the hand).


There is no way that a block on the end of a foot long pole can be considered 'a block on the keel stiffening timber'.

Can we please have a definitive ruling on this before I go to the effort of replacing the broken system.

If the extension is allowed with bracing - what bracing is allowed - where is it allowed to run to/from? So far as I can see it could be (a) a simple brace along the length of the boat off the top of the c/b case/thwart; (b)two diagonals off the thwart wither side of the c/b/ case (how far off the c/l is allowed?); or (c) a brace running the width of the boat parallel to the thwart.

What is allowed?

If such a system is allowed it will be an increase in cost to the boat & thus upset those wanting to keep cost down - perhaps it could be allowed in tandem with getting rid of the ridiculous & expensive towel rail & allowing a simpler, stronger & more reliable rope/velcro system, thus making the changes cost neutral & simlifying the boat a tiny amount.
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posts and mainsheets

Postby Slow Hand on Wed Jul 16, 2008 8:40 pm

Hi,
I am blonde - so I need clear explanation.

Is a post between the exiting mainsheet block and the (inside) keel of the boat alllowable? (Y/N)

If so, is it also allowable to have it braced to the thwart? (Y/N)

Sorry guys to be so slow!

Sue
1724 nui uma
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How to mount your mainsheet block

Postby Ron_F on Mon Aug 04, 2008 5:54 pm

Hi, your question is answered by this thread:
http://www.sabre.org.au/forum/viewtopic.php?t=1337

cheers,
Ron F******** - Sabre 1009 / OK 698.
Last edited by Ron_F on Wed May 13, 2009 8:51 pm, edited 1 time in total.
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Postby A Trace of Blue - 1666 on Mon Sep 15, 2008 12:51 am

All,

Firstly, no disrespect to Phil J, I have lots of time and respect for him.

I think, looking at all the discussion on this topic, there is a clear need for the question on the mainsheet block posts to be finalised once and for all, and I think that it should go to a comittee decision (Sabre Assoc Rule 1.9)with input from the states before a final ruling is made.

Personally, I like Mike S's reminder: '... a sailing dinghy that is simple in design and construction and relatively easy and inexpensive to build...'.

It is just another expense, and if you want one, and you cannot make this item yourself, you will have to find someone who will do it for you. That can be expensive, unless the association also starts producing them.

If the item does offer some form of performance enhancement, will it then also come down to the 'haves' and 'have nots'.

The Sabre is supposed to be one design.

If a mainsheet block mounting extension is to be accepted, then there must be some form of uniform rules that govern the maximum height of some part of the block above the keel mounting timber, and if bracing the extension is legal, and if so, a statement on how/where.

Just to open up a can of worms, was anything sorted out in respect to boats that are not using the specified boom vang fitting as per the older construction manuals. I don't have the latest construction manual, but the measuring rule does not appear to have changed, so I would expect that webbing strops, T-balls, and Saddles sticking out from inside booms are still not legal.

Can the Comittee, when it gets together next, sort this one out also.

Regards . . .
Peter Wilcox
1666 - A Trace of Blue

God Still Sails a Payne-Mortlock Sailing Canoe!
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Postby andrewb on Mon Sep 15, 2008 10:29 am

A Trace of Blue - 1666 wrote:All,

Personally, I like Mike S's reminder: '... a sailing dinghy that is simple in design and construction and relatively easy and inexpensive to build...'.

It is just another expense, and if you want one, and you cannot make this item yourself, you will have to find someone who will do it for you. That can be expensive, unless the association also starts producing them.


Can the Comittee, when it gets together next, sort this one out also.

Regards . . .


& that goes for the 'towel rail' too
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