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Interesting Sailboats: HULL SHAPE, B/D AND BOAT’S PERFORMANCE


As usual, let’s take a look at how different types of boats and hulls performed on this race to contribute to a better understanding of what makes a sailboat fast on an offshore race. This one has very little upwind sailing, it is almost all sailed downwind and beam reaching. I believe that it would be more interesting if the design of the route in between the Islands gave a more balanced sailing in what regards wind directions, but that’s what it is, and here is well taken into consideration that gentlemen don’t sail to windward. LOL

Skorpios, Swan 125

This year the conditions were perfect, mostly  between 11 and 15kn, conditions that lead to a new race record in multihull and a close call in monohull. As usual, the Mod 70 trimarans were much faster than any monohull and two of them finished almost together, the Argos beating Maserati by 2 minutes….but with Maserati winning in handicap. Odd, when the Mod 70 are supposed to be a One class.

https://yb.tl/C6002022#

This time the big Russian Swan 125 Skorpios beat the Australian Comanche, gaining points as the fastest monohull, a title that for many years belonged to Comanche. The third was Leopard, but far away from these two, which have very similar performance, even if the Swan is considerably bigger. 


PAC 52 Warrior Won

In handicap, the Comanche beat Skorpios and finished  2nd, behind a PAC52, “Warrior won”, that in elapsed time took more 17 hours than Comanche, while Comanche took more 12 hours than the faster trimaran.

If we take into consideration the difference in size and the good TP52 performance in wind balanced races, like the Middle sea Race or the World ORC championship, it is easy to understand that this box rule gave origin to what is probably the fastest all-around type of hull, the one that you should take as a reference when trying to know how fast a performance cruiser is in real-time , or a cruiser-racer is. 

 “Warrior Won” is just a slightly modified TP52, with a bit more draft and a slightly bigger mast, and a 100kg lighter engine. In California, they tried to make a new class, the PAC 52, based on TP 52 hulls, but more turned to offshore racing. It seems that the class ended a short time after beginning and the links for the new class, and for the class’ rules are no more online.

PAC52 Warrior Won

https://www.seahorsemagazine.com/110-content/july-2017/505-out-the-same-mould

https://www.sail-world.com/Europe/New-Pacific-52-class-makes-its-debut-in-San-Francisco/-152490?source=google

I believe the PAC52 class was not a good idea. Why a new class using the same hull, just for having boats that have very similar performances to TP52, that are also used in offshore races? It would make more sense to modify TP52 rule to allow for boats more suited, or comfortable, for offshore work, without diminishing the size or potential of one of the most successful one-class series, the TP52.

While the PAC52 as a one-class was a miss fire, the TP52 series continues successfully now with 23 yachts competing in this year’s Super Series and many TP52 racing successfully in major IRC races or on the world ORC championship. Anyway, in what regards type and shape of the hull and ballast the differences are almost inexistent.

In this race, the PAC52 winner in IRC was not much slower than the VOR 65 and VOR 70 and that says how fast a TP 52 can be, taking into consideration the difference in size, and the fact they have not a canting keel, nor water ballasts, like the VOR65 or VOR 70.

TS5/ORC50 Guyader Saveol

It is also interesting to point out that 3 of these based TP52 were faster than the fastest catamaran, beating the two 50ft cats that were racing, the TS5 and the ORC50, even if not by much.

Typically a TP52 has the maximum allowed beam, or close to it, and the max ballast (or close) and that means for a 15.85m boat, a 4.42m beam and a lead torpedo of 3800kg for a total displacement not lower than 6975kg. If all the others are close to the limit normally the average displacement is a bit bigger, around 7.5T, due to the difficulty of building a boat with the minimum displacement and the maximum ballast.

Mylius 60 Lady First III, teak deck and all

This means a boat with a B/D of a bit over 50% and an L/B (length/beam) of 3.56. The ones that believe that very beamy boats with a low B/D, like the new Hanse 460 can be fast, believe in miracles. The Hanse notwithstanding being much smaller (13.87) is already much beamier (4.79) and with a much lower B/D (26.7% to +50%).

The ballast is needed to give a goop performance upwind and also beam reaching, without having a hull too beamy (more drag), one that would have a bad performance upwind. Even on the IMOCA, which are maximized for downwind racing and therefore beamier, to save weight in ballast at the cost of upwind performance, the B/D is around 38% but you have to take into account that the draft is much bigger than the one of a TP 52 (4.50m to 3.20m) and that the IMOCA have big liquid ballasts.

Above, Mylius 60, below, Hanse 460

So, when someone tries to “sell” you a performance boat with a relatively low draft and a relatively low B/D, “don’t buy it”, and understand that if that boat is fast, it can only be in handicap, not over the water, even if in light winds less ballast can be in some cases an advantage, especially when we are talking of a heavy sailboat.

I am not comparing a TP52 with a Hanse 460, just explaining what makes a sailboat fast and what makes a sailboat slow. Ok, you would say that it is evident, but I am insisting on this because when I said, on the post about the new fat 460 Hanse, that, with less B/D, with much more beam (2.90 L/B) and heavier, the new model would be slower than the previous one, many did not believe and the post comments showed that, based on the polar speeds of both boats published by the brand.

https://interestingsailboats.blogspot.com/2021/10/new-460-hanse-that-doesnt-look-like.html

Mylius 60 CK

Besides, the previous Hanse was designed by Judel/Vrolich, the designer of the boat that won this race, and the designer of many great TP52, while the 460 is designed by a NA without racing pedigree and known for designing boats with a small B/D (Amel 50, Waukiez 42PS).

Back to the race, the first cruiser-racers to arrive were the two mentioned cats, that were closely followed by the first monohull cruiser-racer, a Myliys 60, that contrary to the cats has a luxurious interior, beating the JP54, a more radical cruiser-racer with a canting keel and a beamier hull, more maximized for downwind sailing ( a kind of smaller MOCA adapted for cruising). 

Mylius 60 CK interior

The Mylius 60 has the same L/B (length to beam) as the PAC52 (3.56) and even if made of carbon, due to the cruising interior,it is much heavier than the PAC 52 (D/L) and it has a smaller B/D, that at 38.5% is still a big one for a performance cruiser if we consider the 3.0m draft and a torpedo keel.

This Mylius 60 that was racing is not the fastest version, they have a new more powerful version with a canting keel (60 CK) and if this one is already a very fast sailboat we can only imagine the performance of the new one, that is already on the water and still with a luxurious interior, even if this time a lighter one. You can see it on the post cover.

The first 40class racer, a Cape 40

Here, a post about the smaller but no less beautiful Mylius 50:

https://interestingsailboats.blogspot.com/2021/07/mylius-50-carbon-rocket-cruiser-racer.html

Racing with very suitable conditions and wind direction, the Class 40 were very fast, especially the two first, also fast was the ICE 52, a performance cruiser that arrived close after the 3rd and 4th Class40. A post about the ICE 52 here:

https://interestingsailboats.blogspot.com/2016/12/the-ice-52-had-bad-luck-last-year-it.html

Super fast, were the two JPK 11.80, racing in conditions that would not suit them (compared to the 40class racers), the two first yachts with less than 40ft to arrive. They battled all the race long, winning Sunrise (the winner of Fastnet and the one that should have won the Middle Sea Race) by very little over Dawn Threader.

ICE 52, above and below

A Class 40 typically has a 12.19m length, about a 4.45m beam and displaces only 4500kg. That makes it a very beamy boat with a 2.74 L/B, but contrary to the Hanse, also a very beamy boat, the Class40, has a  favorable drag-to-power relationship and allows it to be very fast, especially downwind and beam reaching. Not so fast upwind, especially with waves, that increase wave drag.

The sail power (RM) is huge on a 40class racer due to a big hull form stability, big ballast tanks (750L per side), more or less 44%B/D on a 3.00m torpedo keel. The Hanse has a 26.7%B/D on a 2.25m bulbed iron keel and no water tanks. Looking at a beamy boat and thinking it will be fast because IMOCA and Class 40 are fast makes no sense, without looking and comparing the way those boats overcome the extra drag a beamy hull brings, to have a favorable Drag/Ratio relationship.

Ice 52 interior

The JPK 11.80, smaller than the 40class racer and with a cruising interior, that was here not as fast as the fastest 40class (but faster than several) and faster than the two Pogo 12.50, is a very different sail boat, a cruiser-racer with a not so good downwind and beam reaching performance, but with an upwind better one. 

It has an 11.80m HL, 3.95m beam (3.0 L/B), it is considerably heavier than the 40class (5950kg), having more ballast, but on a less efficient keel (2.34m draft), with a 44.4%B/D. The JPK 11.80 is probably today the best all-around IRC cruiser-racer of this size. An impressive performance here and even better on the Fastnet and on the Middle Sea Race (a winner in IRC on those).

JPK 11.80

A post about the JPK 11.80 and the JPK 39:

https://interestingsailboats.blogspot.com/2021/11/jpk-39-fast-cruiser-versus-jpk-1180.html

At this point many would want to know why the best 40Class racers are faster than the JPK 11.80, while the fastest Pogo 12.50 is much slower, even on a race that suits it (and not the JPK), and why is it possible to a J122e to have almost the same performance as a Pogo 12.50 when Pogo has a 40class hull (literally).

The Pogo 12.50 hull is from one of the previous Pogo 40class racers, but the main difference is the lack of  750L water ballast, 1000kg more displacement, and even if with about the same ballast (2000kg), a much less effective one, due to a big difference in draft,  2.2m to 3.0m (with similar type keels). The extra displacement gives it a smaller 36.4%B/D (about 44% on a class 40), but that difference would be much bigger if the two boats had the same draft.

JPK 11.80 interior

I should point out that obviously there is also a bigger mast, bigger sail area, a backstay, but all that is only possible because the Class 40 has a much bigger RM, and therefore is able to carry much more sail. I am choosing not to look at the sail areas on this post but to the relation between RM and drag that, in fact, is much more important than looking at sail areas because sail areas would be the ones possible with a given RM.

What makes it possible for a Class 40 to be a ton lighter than a Pogo 12.50 has to do with the boat typology: Class 40 is a racer, with racing accommodations, the Pogo 12.50 is a cruiser-racer with a cruising interior and in this similar to the JPK 11.80 and the J122e, even if regarding those cruising accommodations there are differences in quality and cruising suitability, being the ones from the Pogo and JPK comparable (even if very distinct) and those of the J122e of better quality and probably heavier.

Pogo 12.50 Hermes

Everything in a 40class racer has to do with performance, including the big volume occupied by ballast water tanks, while even if performance is the main drive on the JPK 11.80 design, it is not the only one and the type of sail performance that is desired is different. 

While a Class 40 is designed to have the best performance on trade winds, the JPK 10.80 is designed to have a more balanced wind performance, with a good performance on the trade winds, but a better performance in races with a similar balance between upwind, beam reaching and downwind sailing and also designed to perform well in IRC or ORC racing.

Pogo 12.50 interior

To explain the superb performance of the J122e is more difficult and this boat never ceases to impress me. Two of them were racing here in wind conditions that were far from ideal for this type of hull and even so finished very close to the first Pogo 12.50 leaving the other behind (as well as some Class40) and racing at about the same speed as two J121, that are designed much more as racers, than the J122e, that is a cruiser-racer with a great and comfortable cruising interior.

So, how is this possible?: The J122e, a heavier sailboat, with a not very different B/D, with a lot less form stability, in a race with very little upwind sailing, to have almost the same performance as a Pogo 12.50, and worse than the one of a JPK 11.80? Well, it could happen that the Pogos were badly sailed, but if some excuse can be found for the 2nd one (2hand sailed), the first one was Hermes, a sailboat that is extensively raced (has a racing backstay) and has a good crew.

Juno, the fastest J122e in a coastal race

The J122e has the same length as the Class 40, much heavier (even heavier than the JPK 11.80) displacing 6740kg, it has less ballast than the JPK and less draft, even if it has a bulbed keel (versus a fin one), but it has a sleeker hull, with a 3.63 beam, an L/B of only 3.34 and a 37.8%B/D. Let me explain that bigger yachts tend to have a bigger L/B (that means less beam) and that the J122e is quite a narrow sailboat by today’s parameters and the reason it sails so well, and it is fast, has to do with the relation between sail power and drag (less sail power but also less drag).

Many would say that the J122e has an old-designed hull, and if we look at it in fact it looks like a hull designed 15 years ago (and in fact, it was designed in 2007), but how to explain the boat to be so fast on the water and faster than several J121, that are more recent (2018), from the racing line, and apparently have a more modern hull? 

I would love to see the J122e slightly modified, with a 2.50m draft and a torpedo keel, with the same ballast, a slightly more modern bow to increase LWL and a slightly modified stern that maintained the present hull characteristics but increase substantially hull form stability with stronger winds and at a heel angle just over 20º, or so.

Even so, looking at the market, the J122e is among the boats I prefer among 40ft performance cruisers and it is a pity sales, and desirability by many sailors, are not in correspondence with the way this boat sails. I hope Jboats will do something about it soon, presenting a strongly based new model that can change this situation, because if a boat deserves to be more popular among the ones that like performance cruising mixed with some racing, thisir the one. A nice post about Juno, the fastest J122e on this race, and its family crew:

J122e interior

https://jboats.com/2019-blog/a-family-affair-j122e-juno-2019

However, I don’t want to give the idea that narrowboats, like the J122e are the best solution for overall fast boats. The JPK 11.80 and the TP52 are much beamier. I have talked about the importance of the Drag/Power relation, but it does not tell the whole story and that is why the old America’s Cup monohull, very narrow with a huge ballast and draft was not the fastest of the monohulls with that size.

Hull design, besides drag, has importance in what regards the easiness a boat can plan downwind and the wind speed that is needed for that to happen, and narrowboats go too deep in the water to make that happen easily. So the ability to plan (or foil) is another factor, but one that many times have been overvalued, but that it is a real one. Many have also the wrong idea that boats like Pogo are planing boats and that boats like the JPK 10.10/10.30 or the J122e are not and that is not true even if the wind needed is slightly less on the Pogo type of sailboats.

 

Look for instance at the Ocean Race Europe, where the old VOR65 beat clearly all the newer IMOCA in a race with mixed wings. I believe it will not be the case in the Circumnavigation race where more strong and downwind winds will be met. In the video below you can look at how different types of hulls plan, including the J122 that won that race overall (IRC).


Jangada, JPK 10.10

Also very impressive the Small JPK 10.10 Jangada that arrived not far from the other Pogo 12.50 (both 2handed) that arrived slightly ahead of a Neal 47 trimaran and ahead of all First 40 (40 and 40.7 with a full crew). Note that what impresses me is not the IRC classification, where for instance the first Pogo 12.50 (that sailed very fast) was only 40th, the fastest J122, 26th, the JPK10.10, 25th and the faster JPK 11.80, 18th, but their performance regarding the type of boat and size.

A word for the 2 handed race, that here, contrary to Europe, does not have many adepts. There were only two boats racing, the JPK 10.10 and the 2nd Pogo 12.50. Both finished (congratulations), the Pogo without surprise was faster on the water, and the smaller JPK 10.10, was faster in handicap.

JPK 10.30

About the best and fastest boats for 2handed racing, some posts:

https://interestingsailboats.blogspot.com/2020/02/on-rise-duo-and-solo-offshore-amateur.html

https://interestingsailboats.blogspot.com/2019/09/dehler-30-od-and-jpk-1030-first-movies.html

https://interestingsailboats.blogspot.com/2019/01/j99-versus-jpk1030.html

https://interestingsailboats.blogspot.com/2019/10/sun-fast-3300-beautiful-and-fast.html

Jangada, Richard Palmer JPK 10.10, with already some years (the current model is the JPK 10.30) sailed always in duo, has already a big racing pedigree having not only won many times the 2handed class,  but overall the 2019 RORC Transatlantic Race. Below, on this year’s race where it won the 2handed class.

 

And a final request: this type of posts are less popular on the media but give me much more work and time. Many asked me about a way to contribute to support my work, but I have opted for not to do it. However, if you like the post I ask you to click on the ads because only when somebody clicks them do I receive some cents. On this one and in other posts you like. I would appreciate that and you would contribute to the continuity of this blog.




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