# Ocean Race Sails



## HighCs123 (May 9, 2012)

So what's up with the Volvo Ocean Race boats having the Mainsail cropped off at the top batten? I've noticed other Race boats doing the same. 

Just curious


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## Stumble (Feb 2, 2012)

Are you looking at a picture of them reefed, or referring to the square head main?


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## overbored (Oct 8, 2010)

The sail is not cropped off but has more sail area than a pin head by the addition of the Gaff batten. more sail area is faster. more sail area up high where the wind is. With a standard pin head, the top portion does not do much. off the wind racers gain a lot with a square head sail


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## HighCs123 (May 9, 2012)

After a Google search of square head main, this is exactly what I was looking for. I wasn't familiar with that term before. There's plenty of reading on the subject.


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## albrazzi (Oct 15, 2014)

HighCs123 said:


> After a Google search of square head main, this is exactly what I was looking for. I wasn't familiar with that term before. There's plenty of reading on the subject.


We all want them, just wont work on regular boats, running backstays as well as lots of other fancy rigging needed. They are cool looking. The best we can do is add as much leech as possible when ordering a new main.


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## aeventyr60 (Jun 29, 2011)

Some boats with a bit more "roach" to the main:
https://www.google.co.th/search?q=r...0ahUKEwi-9PP4x-HNAhXLpY8KHSXMD_gQsAQIIQ&dpr=1


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## RichH (Jul 10, 2000)

The 'pointy top' of a triangular shaped sail has been known for many years to produce extreme parasitic drag; the 'pointy top' produces a large 'rotor' of turbulence/drag instead of 'lift'. The 'removal' of the pointy top increases overall sail aerodynamic efficiency. 
This is the exact same reason that modern aircraft use 'winglets' on the tips of their wings - to reduced that 'rotor'. And yes, 'winglets' are being experimented with on 'flat top' mainsails (and jibs, too). 
Birds use flexible & separated primary feathers at the 'tips' of their wings to accomplish the exact same thing. Nature is about 15 steps ahead of sail designers.

Secondly, its been known for almost 50 or more years that a sail that has its leech perpendicular to the horizon is vastly more efficient than a sail that has its leech orientation at a diagonal to the horizon. That square/flat top promotes the leech shape to be increasingly more perpendicular to the horizon; hence, more aerodynamically efficient. The ongoing (experimental) trend is also to rake the mast so as to have the leech even more perpendicular to the horizon.


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## albrazzi (Oct 15, 2014)

I have to wonder if you just sacrifice the top 2-3 ft for that squared edge and sew any kind of wing into it would you be better off. I would guess a big "Maybe" without design backup. And what about racing ratings etc. I would not ask for anything from PRHF but surely if you start winning there would be a rucuss.


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## Stumble (Feb 2, 2012)

albrazzi said:


> I have to wonder if you just sacrifice the top 2-3 ft for that squared edge and sew any kind of wing into it would you be better off. I would guess a big "Maybe" without design backup. And what about racing ratings etc. I would not ask for anything from PRHF but surely if you start winning there would be a rucuss.


I am not sure about the first part of the comment. Square tops don't sacrafice the top they add to the back.

As for rating, it depends on the size of the boat, but adding a square top main generally includes a pretty substantial rating penalty in PHRF. 6sec/mile minimum in most areas, but it could be more depending on the added sail area.


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## albrazzi (Oct 15, 2014)

Purely academic since the only way to square it off with the backstay there would be to lop a few feet from the head. Just brainstorming probably not something I would consider seriously. (I think)


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## overbored (Oct 8, 2010)

You would be reducing sail area and the gain by having the square head would be offset by the drag caused by the bare mast.


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## RichH (Jul 10, 2000)

albrazzi said:


> Purely academic since the only way to square it off with the backstay there would be to lop a few feet from the head. Just brainstorming probably not something I would consider seriously. (I think)


A triangle has ~half the area a rectangle of the same 'base, height' dimensions

(Simplistically) In a 'flat top', you remove the area at the top, but then add approx. twice that area to the top sections of the leech.


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## RichH (Jul 10, 2000)

overbored said:


> You would be reducing sail area and the gain by having the square head would be offset by the drag caused by the bare mast.


Mast is of constant length, therefore you'll have the same drag component from the mast whether the sail is full up with a triangular head or with a flat-top main.
But with a flat top, you 'can' have a shorter mast.


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## overbored (Oct 8, 2010)

one thing I have experienced is that the square head is it's a bit harder to trim in higher wind speeds. on my cruising sail the top tends to open the leach a bit to much. the open leach seems to cause the draft to move back and the boat goes sideways. and won't point very well. the carbon racing main is a different story and the leach is easier to control and points much higher. Still learning new things ever time I sail with the square head main. seems when you trim it right it is fast but when trimmed just slightly wrong it is very slow upwind. lots more power on a reach than the pinhead main.


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## albrazzi (Oct 15, 2014)

overbored said:


> one thing I have experienced is that the square head is it's a bit harder to trim in higher wind speeds. on my cruising sail the top tends to open the leach a bit to much. the open leach seems to cause the draft to move back and the boat goes sideways. and won't point very well. the carbon racing main is a different story and the leach is easier to control and points much higher. Still learning new things ever time I sail with the square head main. seems when you trim it right it is fast but when trimmed just slightly wrong it is very slow upwind. lots more power on a reach than the pinhead main.


Does your headboard have more than one hole? Would seem to be advantageous with different wind speeds to control the leach this way. As silly as it sounds two halyards maybe. Still brainstorming I don't know (I assume) the backstay-less rig with a square head just has the one?


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## overbored (Oct 8, 2010)

no headboard just a ring sewn in. there is the carbon gaff batten on a track slide to the top leach corner. works well. the head is attached to the halyard and the head is pulled to the mast slide with line connected to a lower batten slide. works like an Anomaly headboard used on the bigger Square head sails but those are not needed on a 32" boat. I really think the problem I was having with the cruising main is the sail and it was never cut right and now 4 years old. The Ullman Racing main is a world above.


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## Stumble (Feb 2, 2012)

The issue with square top sails is they require much more leech tension than a pin head. If the leech is opening this much then either you need a stiffer batten (unlikely) or just don't have enough sheet tension on to close it. 

Try cranking down on the sheet and see what happens.


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## lionelmozz (Jul 11, 2016)

That's correct.


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## HighCs123 (May 9, 2012)

Soo, bring back Gaff Rigs, look sexier too.


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