Sail Design. Masthead/batten.

[ade white]

I am currently re-making one of my old sails. this is the mainsail i used at this years inlands and measures 8.5m approx. Although old it is still fast! The re-make will take it to 11.5m, but will it be any faster? This should give me the max size area for 05 rules. I am hoping to stop using the excuse "they have bigger sails than us Joe, so its ok if they are going faster."
So 'big is beautiful' in my eyes and although it will look like 'Nora Batties stockings', I am hoping to test whether I can go faster upwind (under F2 conditions...I sense a lightwind season is ahead).
In my re-make, I am thinking about redesigning the top of the mast to incororate a swivel attachment just above the halyard tieoff. This swivel will be the housing for the top batten. the top of the sail will be the batten. therefore the top of the sail will have no/very little downhaul pressure but still be tensioned on the leech. Can anyone think that this may infringe any rules? the sail top will be more than the square tops and similar to the 18's...
After looking at the 18 rigs and the top of their sails, there is a lot going on, lots of different ideas. On some of these rigs much seems to be wasted even though the twist still looks good. I remember we tried lots of different ideas on windsurfing rigs in the past and, although a different concept, 'floppy- flappy' leeches worked really well, but were only controllable on the massive downhaul tensions and mast stiffness.
I dont intend it being 'floppy-flappy, but, I think I could gain more power/control/speed from the sail being able to rotate and tensioned from the leech via kicker adjustment. At present, i think, we rely on mast/downhaul/kicker but with no rotation. I am thinking also that it may relieve some of batten popping problems we all suffer as well. It could make worse though but i dont see how?
Any comments gratefully received as to me plan before i cut me mast.

[Torchy]

I am hoping to test whether I can go faster upwind (under F2 conditions...I sense a lightwind season is ahead).

I detect some wishful thinking Mr Light Airs Lightning

Haven't had a chance to test my 'easily adjustable upper batten theory' but auto-release of square top seems logical and there is a video on 18footerstv of (I think) Rag and Famish making a big rig work in 18kn (in that case a 'round top').

If I can trace it I'll post it.

[Torchy]

I am thinking also that it may relieve some of batten popping problems we all suffer as well.

Be careful talking button popping problems...Hayley's lurking

[Hayley_Trim]

Lurking eh? c'mon, batten popping aside, this is way too easy.

Although old it is still fast!
So 'big is beautiful'... in my ...'Nora Batties stockings',
I dont intend it being 'floppy-flappy, i think, we rely on... rotation.

(sorry Ade  )But then Roland has just pointed out that we have spent the afternoon driving round searching for a pair of old ladies' drawers ...

[Torchy]

If we keep bumping this post up Ade might get an answer

[MK]

The ERS definition of spar is

Spar
The main structural part(s) of the rig, to, or from which sails are attached and/or supported.

So i would say that your attached part would be part of the spar meaning it is governed my these rules

4.2.1 Spars

The area of spars shall be considered as sail area. The area shall be taken as:-
               
Spar Area = (Spar chord – 100mm) * Spar Length
               
Where: spar chord = the diameter of the smallest circle through which the spar could be passed when stripped of all fittings.
               
If the spar chord < 100mm then the area shall be disregarded.

4.2.4 Upper Limit mark
               
The upper limit mark is to be placed on the mast so that the distance from the heel point of the mast to the upper limit mark plus the vertical distance from the mast step to the lowest point of the hull shall not exceed 7100mm.
               
4.2.5 Sail Height
               
The luff of the mainsail shall not be set above the upper limit mark on the mast. The lower edge of the spinnaker halyard shall not be above the upper limit mark on the mast when at 90O to the spar, each extended as necessary.

So in summary its fine, just dont put it above 7.1m from the bottom of the hull and if you make its section over 100mm it will be considered part of your area

[ade white]

Thanks Mk, from reading the information I think i am within the rules. The ring swivel design would incorporate a slot in section for the top mast head batten. As this is a removable, slot on fitting would it be considered as part of the mast and have to measure within the 100mm rule? I was planning on building a tube section onto the ring for the batten to push-fit into. The ring diameter is no more than 60mm and I could make the tube no more than 40 mm so I could make it that size, if dictated to.
I might need to make a couple anyway to test so is size an issue.

[MK]

Because of the way you are using it to hold up the head of a quadrilateral sail the structural piece is a separate spar, technically a gaff

(v) GAFF
A spar attached at one end to a mast spar to set the peak, throat and/or head of a quadrilateral sail.

It is not a batten as it is attached to the mast spar

Your fitting should be fine, the intention of the rule is to measure in wing mast areas, or other aero type fairings

[ade white]

Thanks MK, Yes i guess it is a variation on the gaff rig, I had'nt thought of looking at it in that way, but i agree. As there is no cam system involved, (yet), it should be quite a simple mod. The thought of the gaff rig measurement rules and the idea that it is so old and outdated doesnt mean in the context, i am thinking it, is outdated and a silly idea. 

...shiver me timbers, cherub with a gaff rig... now that sounds mod!
...now waiting for them scallywagl pirates 'torchy' and 'hayley'...

[Phil Alderson]

You might also need to watch out for:

4.3
SAILS
4.3.1
Material
The sails must be soft sails that can be stowed in sail bags of normal dimensions with
battens fitted (for the purpose of this rule, 'long' sail bags for the stowing of rolled up sails are
regarded as normal).

[Torchy]

Arr Jim Laad!...I'm having trouble with me old gaff me-self...keeps sticking straight up when it should be at an angle...I think I be developin' a gunter rig.

[ade white]

Re rule 4.3 and 4.3 1 no problem there...
Although, as MK has mentioned, I am thinking there maybe an infringment on the spar rules for the rig attachment. I can easily adapt the masthead pad on the sail either by an integral fit or a fitting attaching to the masthead pad. This will be the insert for the masthead batten  Therefore the design mod will be all part of the mainsail.
I dont think the 7.1 rule refers to the max height of sail? Therefore, I still think I am within rules if the sail is higher than the mast?
I think I will continue to make both fittings and bring along to the next measurement session.
(Essentially, in-case I have'nt explained it well enough, if you imagine a 'gooseneck' type fitting slotted onto the top of the mast)- is it legal??? If it is, then the attachment becomes part of the spar. The spar then would protrude higher than 7.1 height. hense the rule break).

[phil_kirk]

Before seeing Maff post i was thinking that it sounds like a gaff.

It's amazing how things come back in fashion.  I suppose old ideas such as a Gaff may work better with the application of modern materials.  Now didn't the gaff go out of fasion because it was harder to control twist (because the kicker hadn't been invented) or for reducing weight aloft when masts could be made in one peice.

Oh, what about a flying jib, stay sail or a top sail Ade? :-)

I've just started reading Frank Bethwaites higher performance sailing and the pitcures of the 18 footers from a couple of hundred years ago were amazing.  They set 4 or 5 additional sails for the downwind legs including water sails which hung below the boom and spinnaker pole. 

good luck

[Phil Alderson]

Other than for the spiniker halliard there are no rules about how sails are attached to spars, however the luff of the mainsail may not be set above the upper limit mark the terms in bold are defined terms in the ERS

[PaulClements]

Hello. All very technical this Cherub Forum. I better get reading. On the subject of sails a flexi fat head can work well if leach tension and mast flexibility are matched to crew weight. Everything flexes a bit absorbing gusts and storing and giving back the energy without disrupting heeling moment too much. Watching Paul Coute sailing last weekend at Chew (from the shore due to shoulder injury) it struck me his rig and sails are the bench mark of system integration.

I have bought Shiny B as the prize at the end of long term pysio and need to sort the sails (all knackered and very old fashioned). Can't justify copying the bench mark so am trying to adapt a replica Rooster Musto skiff sail. It is the right size and arguably should work. The MPS sail and mast are very well matched allowing a lazy helm like me to just lay back on the wire and let the rig do all the work. we shall see...

PS anyone got some foils from a Moth or RS600 they want to loan. I fancy lashing up a fully foiling Cherub just for fun!! Rolland could test it in case it proved dangerous.