# Overlapping versus Blade headsails which is quicker ?



## [email protected]

OK maybe this is a simplistic question but:

Scenario :

Beat to windward in a Force 3-4, flatish water, standard production 21st century cruiser/racer fractionally rigged

Dilemma:

If you have a choice between an overlapping 120% genoa sheeted around the shroud or a smaller say 100% blade jib sheeted to barber haulers inside the shroud. 

Lets assume the blade will get you close to the speed the polar diagram predicts. Will you get anything more from the 120% genoa ?

Which do you go for ?


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## Irunbird

Not quite sure exactly what you're asking. Are you more interested in speed or pointing ability? These things will depend on more conditions than just wind strength- things like hull shape, keel length and ballast, number of crew (more hiking if you're racing, for example). If not pointing ability, and you don't mind a little more heel, I'd go with the 120% genoa, which really isn't that big compared to the blade... What we do on our J24 may be different, but if I have all of our crew (5 total) up to about 18 mph (about F4) of breeze we use the genoa (which is a 140%), and I just use a combination of traveller and backstay to keep the boat flat in the puffs. Wait till one of the mods (like Jeff) answer; you'll get more of what you are asking soon. I'm still kinda new at this.

Ray


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## Faster

Yeah, I think for any specific boat in specific conditions this would be a 'trial and error' situation.. you'll need to figure out which configuration ultimately gives you the best VMG to weather... and what works best in flat water may not work best in chop.

But, as Irunbird said lets wait to see what the 'H's (Jeff and/or Rich) might have to say.


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## RichH

[email protected] said:


> OK maybe this is a simplistic question but:
> 
> Scenario :
> 
> Beat to windward in a Force 3-4, flatish water, standard production 21st century cruiser/racer fractionally rigged
> 
> Dilemma:
> 
> If you have a choice between an overlapping 120% genoa sheeted around the shroud or a smaller say 100% blade jib sheeted to barber haulers inside the shroud.
> 
> Lets assume the blade will get you close to the speed the polar diagram predicts. Will you get anything more from the 120% genoa ?
> 
> Which do you go for ?


On a frac rig, most probably the blade will result in a faster sail plan output .... and enhanced pointing ability.

Reason: a blade 'can' be sheated INSIDE of the shrouds and without fouling on the spreaders .... and can be more easily adjusted to the defining 'slot open' distance. In F3-4 that 'attack angle' (tack to clew) is probably going to be somewhere on that 10° line offset from the tack.

If the 120 fouls with the spreader .... "no soup for you !"

Of course, you yourself have to do 'trials' with reference to correct 'slot open distance' vs. VMG once you get close to your final decision. When youre in this final stage of optimization, forget any so-called backwinding to the main ... simply finalize your plan based on speedo output and VMG.


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## sailingfool

Its pretty clear that any race boats, not constrained by class or formula rules to a non-overlapping headsail, use the largest genoas permitted by the wind strength. 

In a serious race fleet beating to a windward mark in under 18 MPH wind speed, it is unlikely to be a single boat not flying a 150%, other than those boats whose rating/formula/class choses to exclude more powerful headsails. Maybe the more tender boats actually will drop to a 130%...


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## RichH

sailingfool said:


> Its pretty clear that any race boats, not constrained by class or formula rules to a non-overlapping headsail, use the largest genoas permitted by the wind strength.
> 
> In a serious race fleet beating to a windward mark in under 18 MPH wind speed, it is unlikely to be a single boat not flying a 150%, other than those boats whose rating/formula/class choses to exclude more powerful headsails. Maybe the more tender boats actually will drop to a 130%...


Thats not the current trend in maxis and other top class boats, especially with frac. rigs with square top mains, etc. The 'trend' is definitely going towards blades instead of large LP overlappers on FRAC rigs.

With mast head boats the only way you can adequately use a large LP is to shorten up the spreader length and usually to keep it inside that 10° tack-clew line.

Many of the one design fleets and 'development classes' are doing the same ...


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## [email protected]

The spreader length is an interesting point.

On a beamier boat the shroud would presumably hit the deck further out and the spreader would be longer as a result you can't sheet as close inboard. You don't get anywhere near the 10 degree sheeting angle.

So on an older boat(eg a 12metre, contessa, sigma 38 that sort of thing) which is probably not going to be as broad you can get away with the overlapping genoa and still make a good VMG. On a more modern design with a flatter broader hull (TP52, most modern cruiser racers etc) you are going to do better by going for a non overlapping headsail sheeted close to the centre line...

That would definitely explain what I'm see with our Hanse 430.


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## sailingfool

RichH said:


> Thats not the current trend in maxis and other top class boats, especially with frac. rigs with square top mains, etc. The 'trend' is definitely going towards blades instead of large LP overlappers on FRAC rigs.
> ...
> Many of the one design fleets and 'development classes' are doing the same ...


I agree the blade has some current popularity as I day above:
"....other than those boats whose rating/formula/class choses to exclude more powerful headsails."

I cant say what the tread is or is not for maxis, but you see plenty of them still flying overlapping headsails:
2010 Photo Galleries
ANd certainly the VOR70s with their large square top mains, all carry large genoas.

So if you buy a new Swan 42 or J109 whose class headsail is a blade...you race with a blade when you race one-design. But we regularly see one design boats like the J105 or J109 coming out for a race, and we judge what fleet/rating they are racing at...if they are flying a blade, they are racing at their slower "one design" rating, if they are flying a 150%, they are racing at their faster non-one-design rating. Maybe the handicappers need to read this tread?

There are a number of benefits to a blade but I dont think that superior low to mid wind performance is one of them.


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## hellosailor

bill, I'd suggest you have to experiment because among other things it wil depend on the specific boat and rig. For instance, on a J/24 the spreaders may ship from the factory two inches longer than the class association requires. If you're on a stock boat, your 150 will hit the spreaders two inches before it needs to.

But if you cut the spreaders down to the minimum length (yes, take a hacksaw to your rigging!) the genoa now comes in two inches closer and you can point higher without tearing the sail.

Polars? Theories? A good set of polars should in theory tell you what has been found fastest on your boat. All well and good, but sometimes you need to check everything and then experiment. I'd bet the condition of your sails (main and fore) and the shape they take is going to affect that as well, so what works best on one boat, just may not be the fastest on the other.


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## rgscpat

Racers who have to race in mixed handicap fleets also have to consider handicaps whereas one design racers may be funneled into certain sail sizes because of class rules.


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## SchockT

Most racers will go with the most sail area they can carry and still maintain optimum heel angles and helm balance. The potentially tighter sheeting angle that can be gained with the blade is probably not a huge consideration, certainly not if it means you are under-powered in the lulls. I would certainly rather be depowering in the gusts than wishing I had more power in the lulls! That goes double if there are waves. Of course that is also assuming that both sails are in good condition and have decent shape!


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## Jeff_H

When you are talking about modern boats, they are typically fractionally rigged and designed with very large SA/D's with the intent that they will not be sailed with overlapping headsails. The thinking is that this sail plan is more efficient that way and much easier to handle. These rigs are much easier to power up and down (not the same as reefing) and compared with older designs these new boats have a huge amount of stability as relative to thier drag and so can carry this large SA/D in a very wide wind range. 

If there is a short coming to this rig proportion, it is at very deep reaching angles and dead runs in light to moderate wind, where nothing beats raw sail area. In racing, this is completely offset by the use of assymetric deep reaching spinnakers and to a lesser extent, code zeros. Cruising with these boats, you almost never head dead downwind in light to moderate conditions and so can usually get by with reaching at hotter reaching angles and building your own apparent wind when it does not make sense to fly a chute. 

The problem with the Hanses is that they are surprisingly high drag for a modern design, and do not have all that much standing sail area. They are also limited by their next to useless self-tacking set up which means that the normal jib is very small (90% or so), and does not set as well as might be ideal. It sounds like you have a custom set up which may let you use a 105-109% headsail. 

The hot ticket if you are having a custom 'all-purpose' made is to have it made from lighter weight, high modulus- low stretch material, cut slightly full for slightly higher headstay sag, and with a lot of roach and furlable battens. The key is to have the sail maker take physical measurements on ypur boat to maximize the luff, roach and foot length. The design should assume that the jib car is placed as far aft as possible but not so far aft that sheet hits the shroud when power reaching. 

If done properly this results in a sail with excellent performance across an extremely wide wind range. The light fabric, larger area of the roach, and fuller shape works well at the light end of the range. As the breeze picks up, the backtstay adjuster can be used to remove headstay sag and flatten the sail. The low stretch fabric allows the sail to be carried well into heavier conditions, increasing backstay tension to further flatten the sails and then reefing at the top of the wind range.

I had Quantum build a sail like that for my boat and it has a range from 3 knots well up into the mid to high 20 knot range. Its 3 years old and basically looks like new.


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## Stumble

As mentioned above it really depends on the boat. 

But typically a #2 (say 115-135) is the worst possible sail for any conditions. If you coukd ignore the spreaders and stay you could get a decent sheeting angle on them, but obviously you can't. This requires you to move the lead well outboard of the ideal sheeting angle. A 155 by comparison while having to go just as far outboard, also gets to come much further aft. So the angle between the centerline of the boat, and the line made from the tack to the clew is much smaller. 

This is why most racing boats go from a 155 to the largest inside overlapping sail they can fly (typically a 115 or so). Not because reducing sail area isn't desirable, but because when you reduce area you also increase the sheet angle to such a point that it kills your pointing ability. And for most boats it is faster to be slightly over powered than to have to give up the pointing ability. Though there are boats this isn't true on, particularly very narrow for the leingth boats like an Olson 30, or Hobie 33.


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## SchockT

Stumble said:


> As mentioned above it really depends on the boat.
> 
> But typically a #2 (say 115-135) is the worst possible sail for any conditions. If you coukd ignore the spreaders and stay you could get a decent sheeting angle on them, but obviously you can't. This requires you to move the lead well outboard of the ideal sheeting angle. A 155 by comparison while having to go just as far outboard, also gets to come much further aft. So the angle between the centerline of the boat, and the line made from the tack to the clew is much smaller.
> 
> This is why most racing boats go from a 155 to the largest inside overlapping sail they can fly (typically a 115 or so). Not because reducing sail area isn't desirable, but because when you reduce area you also increase the sheet angle to such a point that it kills your pointing ability. And for most boats it is faster to be slightly over powered than to have to give up the pointing ability. Though there are boats this isn't true on, particularly very narrow for the leingth boats like an Olson 30, or Hobie 33.


That's not necessarily correct. In the area I race in, most boats have a #2 and they will shift down to that before they go with a #3. Perhaps it is because we are in a light to moderate wind area. There are many times when the #1 is too much power, but the #3 is not enough.

Tight sheeting angles on the headsail is not always what you are looking for, and the slot effect of overlapping sails should not be discounted.


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## Jeff_H

I agree that there are some rigs where a #2 is necessary. Its one of my big gripes with the CCA and IOR era rig proportions where the 155's are too big once the wind gets over a certain point, yet the jib is the prime motivator so that you can't afford to go down to a #3. 

The original poster is talking about a modern fractionally rigged boat, where you don't need the extra sail in a #2 since you can power up and down to fill the gap, and frankly, due to the rig geometry a #2's lousey sheeting angle becomes the limiting factor for the whole boat when going upwind.


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## RichH

Simply look at JeffH's avatar ....

Youll notice immediately that the leech of the jib is (for the most part) operating in close proximity and 'just before' to the 'point of maximum draft' (POMB) in the main. What this positioning of jib's leech to POMB of the main is doing is yielding maximum 'bootstrapping' of two sails or which affects the best 'dumping velocity' from the jib to the main ... for maximum interaction flow between the two sails. Once the jib leech overlaps beyond or aft of the POMB of the main, aero-efficiency of the combo will start to rapidly decline .... although one can 'muscle' more speed (but not necessarily more 'lift' in direct proportion to the increase in SA) by increasing SA with a larger overlap. 

I perceive this configuration is why the 'modern' frac rigs are generally carrying a lower LP jib and rarely a large LP jib ... for the combo of best boat speed AND pointing ability irrespective of 'sail area' considerations alone, ... also ignoring the geometry problems associated with sheeting angles on large headsails. 

Whether this config. was determined aerodynamically or simply iterated by trial and error, it 'seems' to be in accordance with that which theoretically generates maximum aerodynamic conditions and output.


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## WDS123

OP mentioned he sails at his Polars with the Blade. 


Question would then be can he sail better than his Polars with a 155 ? 


I doubt it.


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## puddinlegs

Jeff_H said:


> The problem with the Hanses is that they are surprisingly high drag for a modern design, and do not have all that much standing sail area. They are also limited by their next to useless self-tacking set up which means that the normal jib is very small (90% or so), and does not set as well as might be ideal. It sounds like you have a custom set up which may let you use a 105-109% headsail.


Jeff, having just seen a Hanse 47, we watched the owner's crew takes down the self-tacker _(yes, it's a really odd set-up... from the track, to the base of the mast, up the mast, in the mast, back down the mast, back to the cockpit )_ and hoist a standard jib lead to standard genoa tracks/adjustable lead cars on the deck while preparing to race. I'm sure the boat sailed much better with the standard jib than with the self tacker. IMHO, self-tackers without a boom are pretty much useless, but I'm not expecting anyone to share my small thought on the matter.


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## RichH

puddinlegs said:


> IMHO, self-tackers without a boom are pretty much useless, but I'm not expecting anyone to share my small thought on the matter.


Totally agree you. Without a (vanged) 'boom' or clubfoot there is no effective way to control 'twist' when the clew is outboard. This is usually always seen especially on cutter rigs with only staysl and reefed main flying ... without a means to prevent the clew from rising, the upper panels of the stay'sl will be unattached to airstream flow/stalling, the foot overtrimmed and only a small zone of the middle part of the sail 'actually' working ..... same thing with almost ANY jib when the clew is well outboard. Even with fore/aft fairlead, etc. adjustment, etc. to control clew height ... with a sans 'boom' arrangement the jib will 'naturally' become deeper drafted .... more powerful but 'slower' when the clew is well 'outboard'. FLAT is faster in most conditions (in relatively flat water, etc.)

In the olden days before the 'rules changes' ... a reaching strut or jockey pole was used to help control the 'clew rise'. The Hoyt Boom in this respect is perhaps the best way to do this ... but unfortunately is impossible to apply to an 'overlapping' jib/genoa. 
;-)


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## Jeff_H

Rich,

This is probably the other picture that you really wanted to make your point. Unfortunately we (Synergy and I) are not quite back up on a beat yet.

Jeff








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## RichH

ahhhhhh .... leech timing to perfection. 

;-)


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## Jeff_H

Thanks Rich...


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