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

[flaming]

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?

I still don't understand the point you are making, as it seems completely counter intuitive.

If you're right that designers - and I'm talking about designers here, not websites etc - are now using the "new" method of calculating DLR, then you would assume that a designer specifying a 130% overlapping sail but calculating his DLR based on just the foretriangle, would end up with an overpowered boat since the sail set would then be much higher than he designed for. Since we don't see that, quite the reverse I would argue with most cruising boats with 130+ overlappers being very underpowered, then I don't see what this has to do with anything?

Your general points on the trend in rigs are correct - though I note that you've taken care to frame them negatively "consequently lower ballast ratios" rather than highlight the benefits. (And I'll compare my ballast ratio any day of the week).
What I feel you miss in the advantages to the cruising sailor in modern rig development are the opportunities for better shaped sails as the wind rises, but also the opportunity for better, larger, sails in light winds.
For example, the latest rigs really operate in a kind of hybrid masthead/factional non-overlapping/overlapping way.

When going upwind they set high aspect ratio, fractional, non overlapping headsails with tight sheeting angles. This makes them more efficient upwind. And the ability to carry that full sail into the low 20s of TWS when coupled with a reef in the main means they are well ahead of the equivalent masthead boat that's started furling their genoa.
When reaching in light winds they set masthead "code" type sails that would be the equivalent of a 150% or greater genoa. But coupled with the larger main found on a fractional rig, and being set further forward on a short bowsprit, they're setting a lot more sail. And that sail is also a lighter cloth, as it does not need to be specified as a "1 size fits all roller furler sail". And is cut for reaching, not upwind.

And btw, I'm talking about cruising boats here, not racing boats.

 

[doris]

I still don't understand the point you are making, as it seems completely counter intuitive.

If you're right that designers - and I'm talking about designers here, not websites etc - are now using the "new" method of calculating DLR, then you would assume that a designer specifying a 130% overlapping sail but calculating his DLR based on just the foretriangle, would end up with an overpowered boat since the sail set would then be much higher than he designed for. Since we don't see that, quite the reverse I would argue with most cruising boats with 130+ overlappers being very underpowered, then I don't see what this has to do with anything?

Your general points on the trend in rigs are correct - though I note that you've taken care to frame them negatively "consequently lower ballast ratios" rather than highlight the benefits. (And I'll compare my ballast ratio any day of the week).
What I feel you miss in the advantages to the cruising sailor in modern rig development are the opportunities for better shaped sails as the wind rises, but also the opportunity for better, larger, sails in light winds.
For example, the latest rigs really operate in a kind of hybrid masthead/factional non-overlapping/overlapping way.

When going upwind they set high aspect ratio, fractional, non overlapping headsails with tight sheeting angles. This makes them more efficient upwind. And the ability to carry that full sail into the low 20s of TWS when coupled with a reef in the main means they are well ahead of the equivalent masthead boat that's started furling their genoa.
When reaching in light winds they set masthead "code" type sails that would be the equivalent of a 150% or greater genoa. But coupled with the larger main found on a fractional rig, and being set further forward on a short bowsprit, they're setting a lot more sail. And that sail is also a lighter cloth, as it does not need to be specified as a "1 size fits all roller furler sail". And is cut for reaching, not upwind.

And btw, I'm talking about cruising boats here, not racing boats.

The contrast between the rigs on JPK’s race boats, which are reasonably successful, and their FC range, Fast Cruisers that is, rather demonstrates Flaming’s point.
A genoa plus a solent. Uphill the genoa goes to bed at 15kts tws max, the solent, staysail if you prefer, is quicker and more comfortable.

 

[flaming]

The contrast between the rigs on JPK’s race boats, which are reasonably successful, and their FC range, Fast Cruisers that is, rather demonstrates Flaming’s point.
A genoa plus a solent. Uphill the genoa goes to bed at 15kts tws max, the solent, staysail if you prefer, is quicker and more comfortable.

Well quite.

 

[Roberto]

Dave Gerr, in The Nature of Boats, Eliasson?Larsson, "Elements of Yacht Design", for example, there are many more.

I did the course in yacht design with the then Westlawn school of yacht design and they used the same method. Not only for comparison ratios but also for lead CE/CLR, heeling moment, etc etc. IIRC the same was also used in Skene's.

 

[Chiara’s slave]

I did the course in yacht design with the then Westlawn school of yacht design and they used the same method. Not only for comparison ratios but also for lead CE/CLR, heeling moment, etc etc. IIRC the same was also used in Skene's.

Not surprising some boats end up as a right dogs breakfast then. You’re working with the wrong data.

 

[The Q]

The class I sail in the winter originally had a 140-150% Genoa, (1960s design) almost every one changed that to a 110-120% Genoa as you lost too much time tacking that repeatedly and was hard work on the crew. Now some are trying 100% jibs, it will allow more rapid tacking and even less strain on the crew.

 

[Wansworth]

As a more scientific method is applied the secrets of the relationship between CLR and Centre of the sail plan will e discovered

28 foot AngusPrimrose Commando class had improved balance after adding a three foot bowsprit one amongstmany owner alterations mainly adding a bowsprit and the discovery that vast overlapping genoas are notagreat idea !