Please,a simple answer of why yachts have 130% genoas

[Tranona]

Fully battened mainsail and headsails that hold their shape by way of better cloth and panel layout can make ‘the’ useful difference to weather helm too.

The question is I suppose what might MG have specified had it been available back then? And what changes have caught on across the owners association?
You’re enjoying this new bigger boat aren’t you?

The original rig for the GH 31 had a stumpy 33' mast and under 400sq ft , so long and low aspect ratio. In fact the mast height was the same as my Eventide that was also built by Hartwells. Some had a 36' mast and a bowsprit but that had an adverse effect on stability. The last few had a 39' mast and the option of a cutter rig on a bowsprit but the ballast was increased to meet the stability requirements for CatA of the RCD. Obviously over the years owners have changed rigs - or at least sails but it is difficult to make radical changes. You are right about the effect of good sails. My boat came with a large genoa in Vectran, not made for the boat and it is really too big for an everyday sail so usually sail with 3 rolls in. The main was knackered so Kemps made a new one, but we decided against full length battens because of the low aspect ratio of the sail plus the cost. Instead spent the extra money on a Tides Marine mast track.

What is noticeable with good modern sails is the increase in performance, particularly off the wind. 6 knots is normally a good speed for a GH, but I have found high 6s quite normal - you can tell the difference because thee bilge plates start to vibrate at around 6.3 knots through to 6.6. Owners of original boats rarely mention achieving these sorts of speeds, nor vibrations from the plates! I am in the process of moving the inner forestay and furler 30cm down the mast to take a working jib and then having the Vectran genoa on the outer stay on a furler for off wind work in lighter airs.

Unfortunately I shall never really get much use out of the GH. I bought it as a project but it has all taken too long and I am running out of active years. I did get one reasonable season and learned a lot which has informed the current works but TBH I somewhat regret selling my Eventide as it was a well sorted boat but when I got it all back together after a long period of layup and my dalliance with modern Bavarias I found it all too cramped for my aging bones. While the GH is effectively just a bigger version of the same design with more space to me it does not feel the same. Maybe it is rose coloured spectacles, but I sailed the Eventide all over the channel for over 30 years and it always seemed so perfect for me - like a comfortable pair of shoes

 

[zoidberg]

"The original rig for the GH 31 had a stumpy 33' mast and under 400sq ft , so long and low aspect ratio...."

That drags me back more than 50 years, to the GH31 used by Terry Erskine as a demo boat out of Alec Blagdon's yard ( before Mayflower Marina ). She was called 'Trigger', as I recall, and was commissioned/owned by Lt. Col. George Cross (!), a Plymouth man who hijacked me as 'nav/crew' on several trips to St. Malo with the RWYC and to Jersey as Captain of the Devon Rifle Team, where he and his mates had to compete in an annual shooting competition.

AIR, we had side-trips to Les Ecrehous and into the Minquiers, 'chaperoned' by one or other of his Jersey opponents.

 

[Wansworth]

The original rig for the GH 31 had a stumpy 33' mast and under 400sq ft , so long and low aspect ratio. In fact the mast height was the same as my Eventide that was also built by Hartwells. Some had a 36' mast and a bowsprit but that had an adverse effect on stability. The last few had a 39' mast and the option of a cutter rig on a bowsprit but the ballast was increased to meet the stability requirements for CatA of the RCD. Obviously over the years owners have changed rigs - or at least sails but it is difficult to make radical changes. You are right about the effect of good sails. My boat came with a large genoa in Vectran, not made for the boat and it is really too big for an everyday sail so usually sail with 3 rolls in. The main was knackered so Kemps made a new one, but we decided against full length battens because of the low aspect ratio of the sail plus the cost. Instead spent the extra money on a Tides Marine mast track.

What is noticeable with good modern sails is the increase in performance, particularly off the wind. 6 knots is normally a good speed for a GH, but I have found high 6s quite normal - you can tell the difference because thee bilge plates start to vibrate at around 6.3 knots through to 6.6. Owners of original boats rarely mention achieving these sorts of speeds, nor vibrations from the plates! I am in the process of moving the inner forestay and furler 30cm down the mast to take a working jib and then having the Vectran genoa on the outer stay on a furler for off wind work in lighter airs.

Unfortunately I shall never really get much use out of the GH. I bought it as a project but it has all taken too long and I am running out of active years. I did get one reasonable season and learned a lot which has informed the current works but TBH I somewhat regret selling my Eventide as it was a well sorted boat but when I got it all back together after a long period of layup and my dalliance with modern Bavarias I found it all too cramped for my aging bones. While the GH is effectively just a bigger version of the same design with more space to me it does not feel the same. Maybe it is rose coloured spectacles, but I sailed the Eventide all over the channel for over 30 years and it always seemed so perfect for me - like a comfortable pair of shoes

My father bought the plans and we set up the mounds but circumstances meant it was abandoned but I always thought the Eventide a great little boat after watching one put to sea out of Littlehampton ,under full sail in a good breeze it went like a rocket and stiff as a church

 

[Blueboatman]

The original rig for the GH 31 had a stumpy 33' mast and under 400sq ft , so long and low aspect ratio. In fact the mast height was the same as my Eventide that was also built by Hartwells. Some had a 36' mast and a bowsprit but that had an adverse effect on stability. The last few had a 39' mast and the option of a cutter rig on a bowsprit but the ballast was increased to meet the stability requirements for CatA of the RCD. Obviously over the years owners have changed rigs - or at least sails but it is difficult to make radical changes. You are right about the effect of good sails. My boat came with a large genoa in Vectran, not made for the boat and it is really too big for an everyday sail so usually sail with 3 rolls in. The main was knackered so Kemps made a new one, but we decided against full length battens because of the low aspect ratio of the sail plus the cost. Instead spent the extra money on a Tides Marine mast track.

What is noticeable with good modern sails is the increase in performance, particularly off the wind. 6 knots is normally a good speed for a GH, but I have found high 6s quite normal - you can tell the difference because thee bilge plates start to vibrate at around 6.3 knots through to 6.6. Owners of original boats rarely mention achieving these sorts of speeds, nor vibrations from the plates! I am in the process of moving the inner forestay and furler 30cm down the mast to take a working jib and then having the Vectran genoa on the outer stay on a furler for off wind work in lighter airs.

Unfortunately I shall never really get much use out of the GH. I bought it as a project but it has all taken too long and I am running out of active years. I did get one reasonable season and learned a lot which has informed the current works but TBH I somewhat regret selling my Eventide as it was a well sorted boat but when I got it all back together after a long period of layup and my dalliance with modern Bavarias I found it all too cramped for my aging bones. While the GH is effectively just a bigger version of the same design with more space to me it does not feel the same. Maybe it is rose coloured spectacles, but I sailed the Eventide all over the channel for over 30 years and it always seemed so perfect for me - like a comfortable pair of shoes

(Short response )
Well that all sounds most interesting.

“Never go back” , they do quip?

I’ve known people who have bought their old boat back but hmm, ambivalent perhaps?
I think that 7 ages or more of mankind is a real thing whether we like it or no.
We don’t bend nor accommodate the bruises, cold exposure and pokey berths of youth? But we gain too.

To me on the sidelines it sounds like one final push on the sails front and you will have a sorted, solid reliable easily managed boat there. One that works across our typical uk wind speeds and conditions without fuss And that has got to be smart futureproofing?
One that demonstrably will get you out of trouble and have that big boat heft to offer sailing and comfort across a longer sailing season perhaps. So, man maths at best !

I’ve always liked them, I’ve sailed only one, I hope you pop up photos of the revised foretriangle etc .
I too shifted the slutter rug around in my last boat,having revisited the drawings and in the wake of others experiences and for the better I felt.

 

[Laser310]

In addition to IOR and other racing rules.., there is also the issue of the technology available at the time.

To get equivalent sail area with a higher aspect sail plan - a non-overlapping jib.., requires a taller mast.

a taller mast probably means the center of effort of the sail plan is higher

a higher center of effort means the boat has to be stiffer, so the center of mass of the keel needs to be lower

a stiffer boat develops higher loads on standing and running rigging, sails, deck hardware etc.

and so on...

this all required new technology that evolved along with the boat designs- different mast sections, even carbon masts.., fin keels and bulb keels.., high tech sail cloth, low stretch ropes, blocks with high tech plastic bearings...

Now, I am not saying they couldn't build a boat with a non-overlapping jib ages ago - I owned two keel boats (about 33ft) that were designed in the 1930's that had small fractional non overlapping jibs. The main sails were enormous - mostly because the booms extremely long by modern standards. the boats were very tender - again, by modern standards, and the CE had to be kept low.

 

[Roberto]

I have one (IOR style rig with 130% genoa) with ortogonal spreaders and would not swap it for anything else, should I buy another boat it would be top of priorities (like not having teak decks, no saildrive, etc etc). Main reason: during long runs when wind speed oscillates say 15-25+kt, in particular if reaching/downwind, I leave one or two reefs on the mainsail and then adjust the power by furling/unfurling the genoa, having a tiny jib then reef/unreef all the time surely not for me. Additional reason, with a largish genoa and non-swept back spreaders I can reef/unreef without ever going to windward, there are other methods of doing that on boats with different rigs but what I do works very well for me. 130% because if the wind speed is so low as to need a 150% (which I had) I usually start the engine
This thread is in the ''Yacht racing'' forum section so probably all this is OT.

 

[Birdseye]

Went to see a yacht built in the 1980s it had a small main and a massive 130% Genoa that as the owner remarked over powered the boat.How was it thought a massive Genoa could work as a light weather sail and a strong wind sail and what happened to the bigger mainsails and smaller jibs?

I always thought that this was a fashion thing, possibly linked to the then racing handicap system. Similar in a way to boats like the old Sadler (32?) having a stern almost as pointed as the bow.
Fashions change - when did you last sail a ketch? Or a gaff rig? Most modern boats are now fractional which is a return after years of masthead rigs.

 

[Wansworth]

I always thought that this was a fashion thing, possibly linked to the then racing handicap system. Similar in a way to boats like the old Sadler (32?) having a stern almost as pointed as the bow.
Fashions change - when did you last sail a ketch? Or a gaff rig? Most modern boats are now fractional which is a return after years of masthead rigs.

Yes,bring back the ketch’s and yawls….as you mention itsallaboutratings and technical stuff although in my collection ofYachtingWorld annuals ketches and yawls were quite common in the 1960s ….on racing boats

 

[Tranona]

Yes,bring back the ketch’s and yawls….as you mention itsallaboutratings and technical stuff although in my collection ofYachtingWorld annuals ketches and yawls were quite common in the 1960s ….on racing boats

Yawls in the US were indeed fashionable in the 1950- early 70s again owing to rating under the then CCA rules. not only was the mizzen sail area unrated but it allowed the flying of a mizzen staysail. It did result in some elegant boats from designers like S&S and Alden.

 

[Buck Turgidson]

Yawls in the US were indeed fashionable in the 1950- early 70s again owing to rating under the then CCA rules. not only was the mizzen sail area unrated but it allowed the flying of a mizzen staysail. It did result in some elegant boats from designers like S&S and Alden.

https://images.sandemanyachtcompany.co.uk/uploads/boats/0x0_714_166238387164e5e7a974297.jpg

Oh yes!
Concordia Yawl is in my top 3.

 

[Egret]

Twin forestays on IOR influenced boats with masthead rig and big genoas for quick sail change - big genoa on one, smaller iib on the other - hoist new before dropping old - strings to help pull down - elastics on guard rails to tie jib on the deck - always using an efficient fore sail - would have No 1, No 2 and No 3 jib at least. Big genoa on reach - No 1 to windward - or smaller if windy. Rarely used the biggest one.

 

[Laminar Flow]

To be sure, in the days of small main sails, boats were generally fitted with a 150% genny and a No 1 jib. Least all the early boats I sailed on. Living in a light wind area, at least for the summer months, the 150 got the most use.

Currently, and with the general proliferation of furlers, hardly anyone uses a 150 anymore, as there is no hope of partially furling a 150 and still being able to call it a sail. 130% is about the largest size one can furl and even that is touch and go. 110% is better. However, either model can leave some of the older designs a bit under-rigged.

Currently, overlapping headsails are a bit out of fashion, not withstanding the new 150% replacements called a code 0. With the shrouds taken out to the deck edge on ever beamier designs, overlapping headsails for windward work are now quite impossible.
This is reflected in how SA/D is now calculated using the fore triangle only, whereas formerly, it was done using the entire SA that could be carried to windward. This is the only instance I am given to actually suspect a conspiracy.

Not all older hulls can stand more sail or taller rigs. The moment you start adding more ballast to keep the old girl on her feet, you are loosing a big part of the benefit you're trying to achieve. The Golden Hind is a point in case. This is a relatively narrow design, least by contemporary standards and as such there are definite limits to what is possible. Stability increases to the forth power, so even a small increase in beam has a considerable effect. Much more so than adding more ballast.

 

[flaming]

To be sure, in the days of small main sails, boats were generally fitted with a 150% genny and a No 1 jib. Least all the early boats I sailed on. Living in a light wind area, at least for the summer months, the 150 got the most use.

Currently, and with the general proliferation of furlers, hardly anyone uses a 150 anymore, as there is no hope of partially furling a 150 and still being able to call it a sail. 130% is about the largest size one can furl and even that is touch and go. 110% is better. However, either model can leave some of the older designs a bit under-rigged.

Currently, overlapping headsails are a bit out of fashion, not withstanding the new 150% replacements called a code 0. With the shrouds taken out to the deck edge on ever beamier designs, overlapping headsails for windward work are now quite impossible.
This is reflected in how SA/D is now calculated using the fore triangle only, whereas formerly, it was done using the entire SA that could be carried to windward. This is the only instance I am given to actually suspect a conspiracy.

Not all older hulls can stand more sail or taller rigs. The moment you start adding more ballast to keep the old girl on her feet, you are loosing a big part of the benefit you're trying to achieve. The Golden Hind is a point in case. This is a relatively narrow design, least by contemporary standards and as such there are definite limits to what is possible. Stability increases to the forth power, so even a small increase in beam has a considerable effect. Much more so than adding more ballast.

Who’s now calculating SA/D using foretriangle area not full SA? Certainly not on my IRC certificate…

 

[Chiara’s slave]

Our Code 0 isn’t a 150% substitute, I doubt if any more conventional boats would think of it that way.

 

[Laminar Flow]

Who’s now calculating SA/D using foretriangle area not full SA? Certainly not on my IRC certificate…

Dave Gerr, in The Nature of Boats, Eliasson?Larsson, "Elements of Yacht Design", for example, there are many more. Following, a quote from the first online calculator I opened:

Compare Like for Like (esp. Foretriangle Area)​

It is important to try and compare “apples with apples” with this ratio.

The sail area is normally calculated as the sum of the foretriangle area and the mainsail area.

A good approximation is to use the main plus jib or solent (upwind sail area) but bear in mind that a genoa will overstate the SA/D and a self-tacking solent will likely understate it.

One trick is to apply a manual adjustment to the foresails as follows:

Self tacking jib 90% of foretriangle. So add 11% to the solent area for the calculation.
Jib 110-120%. Use 91% of the overlapping jib area (100/110)
Genoa: 130-150%. Use 77% of the genoa area (100/130).

 

[Chiara’s slave]

That’s certainly a simple answer to the question.
Q. Why do some yachts have 130% (and more) overlapping jibs?
A Because some idiot decided to measure sail area just using the foretriangle.

 

[flaming]

Dave Gerr, in The Nature of Boats, Eliasson?Larsson, "Elements of Yacht Design", for example, there are many more. Following, a quote from the first online calculator I opened:

Compare Like for Like (esp. Foretriangle Area)​

It is important to try and compare “apples with apples” with this ratio.

The sail area is normally calculated as the sum of the foretriangle area and the mainsail area.

A good approximation is to use the main plus jib or solent (upwind sail area) but bear in mind that a genoa will overstate the SA/D and a self-tacking solent will likely understate it.

One trick is to apply a manual adjustment to the foresails as follows:

Self tacking jib 90% of foretriangle. So add 11% to the solent area for the calculation.
Jib 110-120%. Use 91% of the overlapping jib area (100/110)
Genoa: 130-150%. Use 77% of the genoa area (100/130).

So not the people actually doing anything with the data - like the rating authorities - then?

 

[Laminar Flow]

Well, the people doing things with this data are designing boats and thereby determining whether the poor thing has enough SA relative to it's displacement to come up with a decent performance. I'm not sure that qualifies as nothing.

In this sense, I used this ratio to determine how much I wanted to increase SA on our tub, after calculating her stability and to ensure she could carry it as well.
In keeping with the older methodology, I used the entire SA that the boat could carry to weather.

As you might suspect, I'm not terribly concerned how the racing authorities come up with their numbers.

A Because some idiot decided to measure sail area just using the foretriangle.

That pretty much sums it up. Because the racing authorities "forgot" to measure any overlap, though they did eventually cotton on to it, a few years later.

 

[flaming]

Well, the people doing things with this data are designing boats and thereby determining whether the poor thing has enough SA relative to it's displacement to come up with a decent performance. I'm not sure that qualifies as nothing.

In this sense, I used this ratio to determine how much I wanted to increase SA on our tub, after calculating her stability and to ensure she could carry it as well.
In keeping with the older methodology, I used the entire SA that the boat could carry to weather.

As you might suspect, I'm not terribly concerned how the racing authorities come up with their numbers.


That pretty much sums it up. Because the racing authorities "forgot" to measure any overlap, though they did eventually cotton on to it, a few years later.

So to be clear, you think that people who are designing boats are using a DLR ratio that uses only the 100% foretriangle, then giving their newly designed boats a 130% genoa.

You are aware that doing that would result in them having significantly MORE sail area than the designer had allowed for? Being overpowered is not a feature of the genoa driven AWB cruising boats I've ever sailed....

Some online "sailboat data" type websites are using foretriange, and indeed a triangle of boom and mast for main area in order to simplify their data capture process. But you cannot seriously believe that people who are actually designing cruising boats are not taking into account the full sail area they are specifying, surely?

As said - the massive genoa and tiny main in racing circles was initially a reaction to IOR doing exactly this, and only rating the foretriangle area. Funnily enough, when they closed that loophole even later IOR boats reigned that right in. And there hasn't been a racing boat drawn with a genoa now since the very early 2000s.

 

[Laminar Flow]

Indeed and to be clear: It used to be the case that the entire (max) SA which could be carried to weather would enter into the SA/D calculation. This included large, 150% gennies.
Over time, this has changed. Now, SA is calculated using foretriangle only and in many instances the main without roach, notwithstanding the fact that some mains have considerable area in their roach and full batten sails increase driving force by 15% on courses up to 60 degr.
When older types have their SA/D recalculated by the current methodology they can end up with very low SA/D ratios.

Newly designed boats rarely carry overlapping sails, least not to windward. This is particularly the case when the shrouds have been taken to the deck edge on ever beamier designs, to reduce compression loads and allow for skinnier, lighter masts and, consequently lower ballast ratios.

Older designs, where the shrouds tend to be further inboard, precisely to allow overlap, and which now have furlers, may carry 130% headsails instead of the old 150% hank-on, for the simple reason that you cannot (effectively) reef the latter. I have no doubt that the proliferation of headsail furling is as much responsible for the reduction in headsail sizes, at least ones that can be carried to weather, as the changes in the racing rules. Losing 20% of your SA for the benefit of furling obviously does not lead to a boat being overpowered. You may have gotten that part a little backwards.

As to why headsail overlap no longer enters into the calculation, I'm not sure, since the old methodology clearly stipulated that it only concerned sails that could be carried to windward, excluding spinnakers, mizzen staysails, etc.
When a rig is designed so hat substantial overlap is impossible in the first place and a calculation methodology is applied excluding all other, perhaps older, variants, I begin to wonder about the reasoning. Marketing perhaps, when the apples with apples excuse is clearly BS?