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    • UnderDawg

      A Few Simple Rules   05/22/2017

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Presuming Ed

Ker Class 40

93 posts in this topic

Class40 can't use carbon for structures, right?

And aft like this without carbon...

 

185709_10151173802147064_1670421017_n.jpg

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I think the aft area is doable in glass and foam. It is an interesting use of the volumes and surface to pick up rudder loads (not sure what the one slanted lateral tube is for; autopilot?) main sheet, steering. Something is really not right where the tiller linkage exits, though.

 

Are the towers aft only for backstays and sail sheeting, or are they supposed to distort the freeboard measurement as well? (Aside, this extreme ramp reminds me of a yacht called Siemens by Mani Frers in the darkest hour of IMS.) If they are done to distort freeboard, and done in conjunction with the relatively deep chamfer on the hull deck, it is a way to push volume closer to the keel, which in turn means you can get more ballast mass without going over the max RM90 value. Of course, that mass will serve well at 15-20 degrees of heel.

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I think the aft area is doable in glass and foam. It is an interesting use of the volumes and surface to pick up rudder loads (not sure what the one slanted lateral tube is for; autopilot?) main sheet, steering. Something is really not right where the tiller linkage exits, though.

 

Are the towers aft only for backstays and sail sheeting, or are they supposed to distort the freeboard measurement as well? (Aside, this extreme ramp reminds me of a yacht called Siemens by Mani Frers in the darkest hour of IMS.) If they are done to distort freeboard, and done in conjunction with the relatively deep chamfer on the hull deck, it is a way to push volume closer to the keel, which in turn means you can get more ballast mass without going over the max RM90 value. Of course, that mass will serve well at 15-20 degrees of heel.

 

Doug,

Thinking the slanted tube in the rudder area is part of a strut system to support the bottom bearing with a kick up rudder. Similar setups in some other C-40s.

Sheerline may be functional but does look very different.

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Could do yourself some serious injury around that traveller and aft cockpit area...

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Could do yourself some serious injury around that traveller and aft cockpit area...

 

And those clutches out of spraywall are real pleasure in crash gybe/emergency situation :D

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I think the aft area is doable in glass and foam. It is an interesting use of the volumes and surface to pick up rudder loads (not sure what the one slanted lateral tube is for; autopilot?) main sheet, steering. Something is really not right where the tiller linkage exits, though.

 

Are the towers aft only for backstays and sail sheeting, or are they supposed to distort the freeboard measurement as well? (Aside, this extreme ramp reminds me of a yacht called Siemens by Mani Frers in the darkest hour of IMS.) If they are done to distort freeboard, and done in conjunction with the relatively deep chamfer on the hull deck, it is a way to push volume closer to the keel, which in turn means you can get more ballast mass without going over the max RM90 value. Of course, that mass will serve well at 15-20 degrees of heel.

 

Doug,

Thinking the slanted tube in the rudder area is part of a strut system to support the bottom bearing with a kick up rudder. Similar setups in some other C-40s.

Sheerline may be functional but does look very different.

 

You know in the back of my mind I had that Class 40 did not allow for the kick up rudder (cost savings, much like stock materials and the limit on trav position). I should know bettter, but really, steel stocks not carbon, but kicking up is allowed?! That's a bit backwards.

 

This boat is going to be expensive, I reckon.

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Mach 40 C-40's have kick up rudders. The backstay/ Code block arrangement looks very similar to the JuanK treatment on the latest crop of VO-70's. Hell, when I first saw the rendering on the FP, I would have bet on a Juanker C-40

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Mach 40 C-40's have kick up rudders. The backstay/ Code block arrangement looks very similar to the JuanK treatment on the latest crop of VO-70's. Hell, when I first saw the rendering on the FP, I would have bet on a Juanker C-40

 

Has JK done a Class 40 yet?

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Sick whip !

I love this radical and aggressive look !

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That cockpit was designed by an orthopedic surgeon with a huge mortgage and 3 ex-wives.

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I think the aft area is doable in glass and foam. It is an interesting use of the volumes and surface to pick up rudder loads (not sure what the one slanted lateral tube is for; autopilot?) main sheet, steering. Something is really not right where the tiller linkage exits, though.

 

Are the towers aft only for backstays and sail sheeting, or are they supposed to distort the freeboard measurement as well? (Aside, this extreme ramp reminds me of a yacht called Siemens by Mani Frers in the darkest hour of IMS.) If they are done to distort freeboard, and done in conjunction with the relatively deep chamfer on the hull deck, it is a way to push volume closer to the keel, which in turn means you can get more ballast mass without going over the max RM90 value. Of course, that mass will serve well at 15-20 degrees of heel.

 

From what I remember freeboard measured is the projection of surface enclosed by sheerline and waterline divided by length, so you might well be right.

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Yes. http://inside.class40.com/contenu/pdf/jauge/en/2013_Class_rules.pdf

 

205. AVERAGE FREEBOARD

The average freeboard must not be lower than 1.10m in measurement trim.

The average freeboard is obtained by dividing the vertical projected surface of the topsides (as far as the sheer line, as defined in the EN/ISO 8666) by the hull length (Lh).

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Yes. http://inside.class4...Class_rules.pdf

 

205. AVERAGE FREEBOARD

The average freeboard must not be lower than 1.10m in measurement trim.

The average freeboard is obtained by dividing the vertical projected surface of the topsides (as far as the sheer line, as defined in the EN/ISO 8666) by the hull length (Lh).

 

Yep. It is going to be an interesting reading of what vertical projected surface of the topsides is for the area behind the helm position. It looks a lot like a measurement trick as was done on IMS Siemens. At that time I think freeboard was something like forward and aft divided by 2. They had to change it to pick up 5 points along the length. Of course the freeboard in a VPP rule was used in a different way then in a box rule. But it is the RM90 max rule of the Class40 that is the culprit here. It is a really easy rule to take advantage of, IMO.

 

92.jpg

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Yep. It is going to be an interesting reading of what vertical projected surface of the topsides is for the area behind the helm position. It looks a lot like a measurement trick as was done on IMS Siemens. At that time I think freeboard was something like forward and aft divided by 2. They had to change it to pick up 5 points along the length. Of course the freeboard in a VPP rule was used in a different way then in a box rule. But it is the RM90 max rule of the Class40 that is the culprit here. It is a really easy rule to take advantage of, IMO.

 

 

You mean with the chamfer?

213 – GEOMETRY OF THE HULL

From 150mm under the sheer, any point vertically below must be closer to the centreline than the point

immediately above, no matter which section.

 

Spread over the whole length, that gives a good loss of buoyancy at 90 degrees compared to the similar shape without it. As you said, I'm curious to see how the area behind the rudder measures in terms of sheerline. Might be detailed in the ISO standard, or he asked the class their thoughts about it.

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Yep. It is going to be an interesting reading of what vertical projected surface of the topsides is for the area behind the helm position. It looks a lot like a measurement trick as was done on IMS Siemens. At that time I think freeboard was something like forward and aft divided by 2. They had to change it to pick up 5 points along the length. Of course the freeboard in a VPP rule was used in a different way then in a box rule. But it is the RM90 max rule of the Class40 that is the culprit here. It is a really easy rule to take advantage of, IMO.

 

 

You mean with the chamfer?

213 – GEOMETRY OF THE HULL

From 150mm under the sheer, any point vertically below must be closer to the centreline than the point

immediately above, no matter which section.

 

Spread over the whole length, that gives a good loss of buoyancy at 90 degrees compared to the similar shape without it. As you said, I'm curious to see how the area behind the rudder measures in terms of sheerline. Might be detailed in the ISO standard, or he asked the class their thoughts about it.

 

There are two things at work. One is the chamfer, which in the current C40 rules is pretty well handled (wasn't always that way). You have said the same. The other point I am making is that if you call those 1950's tail fins part of the "vertical projected surface of the topsides" you have a nice big area, the length is constant, and you can lower the deck in the middle of the boat (and most importantly the part that is submerged at 90 deg heel) within the rule. This amounts to moving the displacing volume down towards the keel. And it lowers the deck CG, a win win.

 

But, it begs the question, what is topsides in a section where there is no deck, and thus no shearline (which is the virtual intersection between deck and hull)? We did the same hollow scoop on our series Mini, and the freestanding hull shell was called part of the topsides area by the measurer. But we did not go UP, pushing the remainder of the deck down. We did use an S shaped shearline to put more freeboard forward, for reserve volume and deck VCG reasons. The S shaped shear seems also to be the case when you look at the Numeca models of Jason's offering. here http://www.forty1design.com/#/philosophy/4569699040

 

All told, I think this is aggressive move to get more ballast weight and more RM20 without touching RM90. Arms race indeed.

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Hard to tell from the rendering, but it also looks like this boat is going with in line spreaders, a-la the Mach 40's. That should continue to piss of the part of the C-40 class that worked like crazy to have Mare banned

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Looks like another class where a guy could come up with something decent designed on his PC has long lived...

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Looks like another class where a guy could come up with something decent designed on his PC has long lived...

 

I think no matter the age of a class a top designer is going to be able to bring more interesting insights to the drawing board than the average Joe. It's simply a matter of experience and resources.

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Plus there's nothing like experience when it comes to reading rules and looking for what's not written as well as how what is written in phrased.

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I suppose the open volume in each quarter area also reduces RM under static measuring conditions but would stay dry when moving so provides righting moment when under way? Cool trick.

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Looks like an awesome cockpit for a video game and a treacherous one for real life. Don't drop anything and definitely don't fall back there while beating. You'll be broken and wet.

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Hard to tell from the rendering, but it also looks like this boat is going with in line spreaders, a-la the Mach 40's. That should continue to piss of the part of the C-40 class that worked like crazy to have Mare banned

 

This was created by a part of the C-40 class who worked to have Mare banned....

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I suppose the open volume in each quarter area also reduces RM under static measuring conditions but would stay dry when moving so provides righting moment when under way? Cool trick.

The quarters aft of the main trav should be high and dry during 90 deg heel test.

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For those of us who haven't kept up with C-40 politics, what's the story?

 

The Mach 40 boats were the first to have inline spreaders and the ability to adjust mast rake via different strops on the headstay. A faction of the class believed this would add unnecessary cost to the class, and some even questioned the safety of the rig for shorthanded gybing. Mare was repeatedly protested last year, despite sailing with a fixed headstay length for each event. All of the protests were dismissed, but there is some bad blood in the class that persists. I'm sure Rail Meat can add some more to this after the KW Race, since he's been involved in the fray

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So now they're locked at one angle of rake, though according to Riechers tensioning their mast obviously is still possible via the checkstays.

 

I'm wondering what the reasoning behind extending the "single skin" section in front of the mainsheet traveler is. I'd hate to imagine people stepping in there at sea.

 

Also, I don't suppose these will be kick-up rudders, though I may be very wrong there.

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I suppose the open volume in each quarter area also reduces RM under static measuring conditions but would stay dry when moving so provides righting moment when under way? Cool trick.

The quarters aft of the main trav should be high and dry during 90 deg heel test.

I would think the chamfer will be well underwater at 90 degrees and that the chine at the stern would have to be a foot or two under water as well. With a single skin hull aft of the traveler I don't see how it can be high and dry unless the hull rocks dramatically bow down.

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I suppose the open volume in each quarter area also reduces RM under static measuring conditions but would stay dry when moving so provides righting moment when under way? Cool trick.

The quarters aft of the main trav should be high and dry during 90 deg heel test.

I would think the chamfer will be well underwater at 90 degrees and that the chine at the stern would have to be a foot or two under water as well. With a single skin hull aft of the traveler I don't see how it can be high and dry unless the hull rocks dramatically bow down.

So here is a picture of an overweight series mini, our design (first boat out of the mould) not a class 40, but not so very off the mark. The single skin area aft of the traveler, and everywhere else, is also the case in a series mini, by the way. Had the boat been built on weight, the "scoop" or hull extension would have been out of the water. I don't think the chamfer dimensional difference is enough to make a difference.

post-699-0-41267000-1358373178_thumb.jpg

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To add to what Doug said, here are two pics hull #2 of the Nacira mini getting its pull down test done. The hull-transom corner was just kissing the water.

 

Agree with Thomas on the cockpit floor opening forward of the traveler although it is possible this factors in the 90RM too.

 

Guessing that kick up rudders will be an option like the new Verdier (FR Nautisme) boats

post-15809-0-71413100-1358374930_thumb.jpg

post-15809-0-55320400-1358374932_thumb.jpg

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Thanks for the photos. I should know better than to argue with a designer, but it will be fun to see the RM90 photos. Seems like the 40 has less of a wedge shape so may not float so bow-down. Can't think of a better reason for the ankle breaker sole.

 

Lessons from the Vendee: Where are the solar panels and how do the hydrogens mount?

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Thanks for the photos. I should know better than to argue with a designer, but it will be fun to see the RM90 photos. Seems like the 40 has less of a wedge shape so may not float so bow-down. Can't think of a better reason for the ankle breaker sole.

 

Lessons from the Vendee: Where are the solar panels and how do the hydrogens mount?

Here is a Class 40

0BF774DC7D8C66D38025737C005CAD0A_topl_1.jpg

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For those of us who haven't kept up with C-40 politics, what's the story?

 

The Mach 40 boats were the first to have inline spreaders and the ability to adjust mast rake via different strops on the headstay. A faction of the class believed this would add unnecessary cost to the class, and some even questioned the safety of the rig for shorthanded gybing. Mare was repeatedly protested last year, despite sailing with a fixed headstay length for each event. All of the protests were dismissed, but there is some bad blood in the class that persists. I'm sure Rail Meat can add some more to this after the KW Race, since he's been involved in the fray

 

And I am back....

 

Yes, the Mach 40's were the first (and still only) design for in-line spreaders. And yes, there is a faction of the Class that is not fond of the mast design. The reasons Ryano gave are the ones voiced by this faction, although I think the comments about the safety were mentioned about as frequently as the comments about their contribution to an arms race. I think it would also be fair to say that more people disliked the Mach 40 mast than those that supported it. It was, however, considered legal under the rules that were in place at the time the first boat in this design (104) was splashed.

 

The entire dialogue around the Mach 40 was heated, and had a great deal of involvement by members of the class. The individuals that were the leaders on either side of the debate were passionate and forceful in their position. i think it fair to say that some people probably are not on very friendly terms following the shouting.

 

The rule changes voted in last February (effective now) are that head stay lengths are fixed. It addresses part of the issues voiced around the Mach 40 rig, although does not address the issue of in-line spreaders.

 

 

The rule changes that were voted on last year don't go into effect for one year because of the way the Class Constitution is written. The one year window applies to all changes and was an effort to ensrue that members would have time to react to changes, but it had the unintended consequence in this instance of allowing an unpopular design feature to remain in play for 2012. This was attempted to be addressed by a decree from the Class President that dictated fixed head stay's during each event, although this decree was also a bit problematic since the Constitution is not entirely clear if this path was open to fixing the problem.

 

On a side note, one of the issues of protest last year were around the fact that Mare did not actually fix their head stay for the duration of an event, and instead chose to modify their headstay length prior to the 3rd leg of the Atlantic Cup. Suffice it to say, it was not a welcome move amongst the majority of the competitors.

 

 

As for the Ker - I agree about the comments regarding the comfort (or lack thereof) of the cockpit. And the intent of the unorthodox freeboard sure would seem to be a play on RM 20. But.... the Class 40 is a Box Rule, and it would be foolish to expect that designers, builders and owners are not going to search for ways to push the rule. The trick is in trying to have a rule loose enought to allow for cost reasonable innovation and yet also tight enough to avoid an arms race that would make earlier boats obsolete and turn people off from the class. Up to now, I think we have done a reasonably good job at this balance. The results from numerous races show that any given design can be at the front of the pack or back of the pack depending on the race. Different conditions favor different designs, and in all the races the skipper skill trumps design. No matter what any one feels about Reichers personally, even when Mare was sweeping up prizes, it is pretty undeniable that Jorg is a very good sailor and puts other very good sailors on his boat when it is crewed.

 

For the Ker....I have not thought enough about it yet, or talked with enough people to figure out what my position would be on the innovations that are showing up in these renderings.

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Since there are some interested parties reading this thread, I should probably also use as an opportunity to give a little update about the Annual Meeting, and the process for Rule changes.

 

The Class attempts to bring stability to the Rule by having a process that proposes and votes on changes to the Rule every 4 years, with a one year lag in implementation. The exceptions to this are two: one involves any changes that are considered required based on safety. The introduction of a requirement for a stern hatch was one such off-cycle exception. The second exception is if there is a call for an "extraordinary" AGM. For such a meeting, there is a super majority requirement to get things passed, but it is a vehicle to take care of issues that otherwise can't be voted on until either another AGM or (in the case of Rule changes) until the end of the 4 year cycle. We have resorted to this process once, when the results of the AGM were so contentious that we felt it necessary to have an EGM.

 

The directors of the Class (and the majority of members who have shared their thoughts with the directors) continue to be very focused on controlling costs and avoiding an arms race that makes older boats obsolete. There is a sub-set of the directors who are currently working on various proposals on how to adjust the rule to continue to control costs, some of which will be dicussed at this coming weekend's AGM in Caen. Since this is not an EGM, there will not be a vote on any changes at this meeting but instead just a discussion to gather thoughts from the class members in attendance. There is a possiblity that an EGM might be scheduled for later this year, should there be enough concensus around any particular proposals. Things being discussed include sails (material limits as well as limits on new sails per season) and the topic of lifting rudders.

 

One of the other subjects that has been a topic of conversation from the members is the inconsistent approach towards scruitineering. Some races are quite strict, others have non-existent scruitineering and then there are varying lists of equipment from race to race. There is a general desire to see stricter scruitineering at each race, a desire that is challenged by the fact that the Class administration is actually very small and there is no staff to travel from event to event just to perform the scruitineering. The directorship is working on ways to try to improve and harmonize the process.

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Curious on your thoughts regarding lifting rudders. If I was looking to do an event like the GOR i a Class 40, I'd conducer the lifting rudder to be a necessary element in UFO risk management, not just overall drag reduction. Has anyone done a VPP study to rate the drag benefit of a lifting rudder over the course of an event like the St. Malo Race?

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My thoughts (for what limited value they might be worth) on lifting rudders is that they add a considerable amount of engineering and cost to a build. Costs that make the question of stainless versus carbon rudder stocks look trivial. I am not certain if the people first involved in drafting the Class Rule really realized exactly how much of a cost impact they would have on a build, but that cost has become more evident in the last couple of years when transom mounted rudder engineering issues actually bedeviled several build projects.

 

In a world where the majority of the Class is concerned about cost control (and arms race), I think it merits a full discussion amongst the owners to see if people want to continue to allow them. And that discussion is slated to occur, as part of the cost containment effort a group of the Directors has been focused on. In fact, it is on the AGM agenda for this coming weekend.

 

I get the issue of UFO risk management, but I can think of only one instance in the past 10 years of Vendee where an under hung rudder had a UFO collision that resulted in damage (Bubi, this time around). Far more performance issues have occured with boats that had transom hung rudders, a data point that is true on an absolute basis but I think would be true even if you adjusted it to be relative to the number of under hung versus transom hung boats.

 

In terms of drag reduction, no one in the Class has done a study but I do know from extensive discussions with Merf Owen that OCD has done both tank and VPP studies and they actually prefer the underhung rudders. There are questions and trade offs between drag, end plate effect, the propensity for failure and weight amongst other things. But I also know that the French sure seem to prefer transom hung, kick up rudders and to some degree this is a "monkey see, monkey do" phenomena.

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Wow. real, factual discussion on SA. Hell has frozen over! Any plans for a Dragon 2 in the near future?

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For better or worse, no plans for a Dragon 2 at the moment. Simply too much money when there is a 150 year-old house that needs interior renovations.

 

But I am not really convinced that I need a new boat. In terms of ergonomics and equipment reliability I think we finally have got the boat well sorted after making a number of changes. The only thing I would want that I can't have without a new boat would be control lines lead through the cabin to a central and forward bitch winch,

 

From a performance perspective, we had a chance to race against a large fleet in 2012 that included brandh new designs and vintage designs, and we did so in a wide range of conditions. in some conditions we were slower and in others we were faster so I am not convinced a new boat is going to buy me a huge increase in performance. If I had a performance wish list, it would involve improving deep running performance, squeezing some speed out of the deep reaching, and helping improve the agility and speed coming out of tacks and gybes.

 

So instead I am looking at a refit to whittle a little weight out of the boat to get it to class minimums, widen the sweet spot and ultimately improve performance on the margin. Some of the changes being contemplated include a nose job to switch to an articulating sprit, and potentially a new rig. Between those two changes, I bet we could get 3% improvement in performance for a fraction of the cost of a new boat.

 

The bigger opportunity for speed improvements involve me become a better sailor.

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For better or worse, no plans for a Dragon 2 at the moment. Simply too much money when there is a 150 year-old house that needs interior renovations.

 

But I am not really convinced that I need a new boat. In terms of ergonomics and equipment reliability I think we finally have got the boat well sorted after making a number of changes. The only thing I would want that I can't have without a new boat would be control lines lead through the cabin to a central and forward bitch winch,

 

From a performance perspective, we had a chance to race against a large fleet in 2012 that included brandh new designs and vintage designs, and we did so in a wide range of conditions. in some conditions we were slower and in others we were faster so I am not convinced a new boat is going to buy me a huge increase in performance. If I had a performance wish list, it would involve improving deep running performance, squeezing some speed out of the deep reaching, and helping improve the agility and speed coming out of tacks and gybes.

 

So instead I am looking at a refit to whittle a little weight out of the boat to get it to class minimums, widen the sweet spot and ultimately improve performance on the margin. Some of the changes being contemplated include a nose job to switch to an articulating sprit, and potentially a new rig. Between those two changes, I bet we could get 3% improvement in performance for a fraction of the cost of a new boat.

 

The bigger opportunity for speed improvements involve me become a better sailor.

 

Where are your ballast tanks?

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If the ring frames are equiditance and the first is under the traveler then the first tank is between the second and third frames and the second tank is between the third and fourth frames. The front face of the forward tank is lined up with the companion way.

 

As a general matter, they are a bit further aft than some of the other boats, but you have to think about it in the context of the bow design, the rocker of the boat and the mast / keel placement. My bow is a bit more fine than some of the more recent designs and as a result having the ability to get water further aft helps me with the down wind run and surfing in a way the more recent designs probably don't need.

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I think RM and Ryano, if you are also reading the VG thread, and I know for a double dog gone fact that you are, that OCD stands out as not using "transom hung" or "kick up" rudders. I think the answer you would get on the topic of "how much is it worth" comes down to who you ask. We did them for Kuka Light, and I am so sure it was the right choice. I don't think, with huge homage to the OCD team, that it is up for grabs and monkey see monkey do.

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Wow. real, factual discussion on SA. Hell has frozen over! Any plans for a Dragon 2 in the near future?

Ah, but it is a hijack, Mr. Ryano!

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I think RM and Ryano, if you are also reading the VG thread, and I know for a double dog gone fact that you are, that OCD stands out as not using "transom hung" or "kick up" rudders. I think the answer you would get on the topic of "how much is it worth" comes down to who you ask. We did them for Kuka Light, and I am so sure it was the right choice. I don't think, with huge homage to the OCD team, that it is up for grabs and monkey see monkey do.

 

I am the least authoritative person in this discussion and have learned through long experience to defer to experts.... It would be interesting to hear you and Merf debate the relative merits of the two approachs.

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I think it's also important that the class doesn't allow designs that look like the batmobile. It's an unfair advantage and supports the wealthy.

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Since the first Ker 40 being launched in the UK in May 2012, designed by Ker Design the McConaghy built Ker 40s have delivered on their promise and exceeded expectations of being an exceptional offshore IRC racing yacht.

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I think it's also important that the class doesn't allow designs that look like the batmobile. It's an unfair advantage and supports the wealthy.

 

Yo - I am in NOLA tonight (Friday the 25th). Call my mobile - love to buy you guys dinner. Would have PM'd you but your inbox is full.

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Great article in this month's Seahorse about this project:

http://www.seahorsem...of-the-ultimate

 

And an article about the latest generation VPLP Class 40 in the same magazine. Good reading.

 

Guessing you meant Guillaume Verdier not VPLP?

 

Fair point.

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So what is the advantage of a chamfer anyways? I don't get it.

 

 

 

 


You mean with the chamfer?
213 – GEOMETRY OF THE HULL
From 150mm under the sheer, any point vertically below must be closer to the centreline than the point
immediately above, no matter which section.

Spread over the whole length, that gives a good loss of buoyancy at 90 degrees compared to the similar shape without it. As you said, I'm curious to see how the area behind the rudder measures in terms of sheerline. Might be detailed in the ISO standard, or he asked the class their thoughts about it.

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The RM90 of the boat is limited. Imagine the waterplane of the boat when it is knocked down (see photos). Everything that pushes that center of volume closer to the bulb, including the chamfer, lowers the value of RM90. But at 20-30 deg heel this chamfer or deck treatment means nothing. You can keep sailing RM without adding RM90 when you have a big BIG chamfer. Years ago, I suggested that you could make the chamfer like 40 cm or more, right up to the point that the deck goes under in normal sailing conditions. Because at that time it was totally unregulated, I saw a big gaping hole in the rule. An RM90 rule depends on a freeboard rule and a chamfer rule.

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Looks very different than the rest of the class, be interested to hear what RM thinks about it.

 

Looks like it could be a very wet boat.

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I normally find ker designs to be attractive and sexy from an aesthetic and functional point of view... this boat is just functionally sexy.

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It's really ugly, but not in the endeering way that the scow mini is. For everyone's sake, I hope it's fast.

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I have no opinion on the aesthetics. For those that love Dorade's aestgetics, any Class 40 probably hurts their eyes. Beauty is in the eye of the beholder.

 

As for function, they are clearly aiming for on specific area of perceived gain under the rule, in addition to other less impactful design benefits. It will be interesting to see how it works.

 

Each of the 4th gen boats seem to acheive a benefit in one small set of conditions but the reality is that the fleet as a whole remains tightly packed in virtually every race and almost any design and generation can win with perhaps only 1 or 2 exceptions. The fast sailor wins.

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An extreme boat, probably fast and surely well built by McConaghy.
Is it a Class40? Not from my point of view...
Extremely low freeboard in the aft cockpit sections, in order to lower the CoG and to exploit the inherent deficiencies of the 90 degrees righting moment test to the extremeand without regard to the idea of the rule.
Only by adding the VO70 style batwings to the stern it is in theory possible to calculate an average freeboard which satisfies the requirements of the Class40 rule.
But: can there exist a freeboard where there is no deck. There is no hull/deck intersection in the batwing area, thus these surfaces cannot be calculated in the freeboard measurement.
Why was there an average freeboard rule in the beginning? To create safe offshore going boats.
I stronghly doubt the Ker40 is such a boat.

The other point is that the boat is promoted as a one-design within the Class40, thus helping to splitt the unity of the Class and complicate matters.
It is difficlt enough to have all the various generations of boats racing against each other, and Class40 surely do not need another group.
The interesting point is that the boat was commisioned by a team, whose money-packed principal in 2012 initiated a crusade against the new, very competetive Mach40 which was absolutely legal with the rules at this moment.
The designer of this boat had used a loophole in the rules, which was opened up by, among others Team Concise.
By the way, Concise's protest was voiced after the first Mach40 won the 2011 "Mondial" in Benodet, where ..as usual.. Team Concise showed up with a purpose-designed 3DL inshore sailwardrobe,
when nearly all other teams used (or by lack of budget had to use) their normal offshore sails

Fair enough, but compared to the wild freeboard interpretation of the Ker40, the Mach40 canting mast was an amiable joke.

The easiest solution would be to let develop Team Concise their one design baot and create their own Class...but not within and on the shoulders of Class40.

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Picture stolen from the "Concise" Facebook page.

 

It actually looks pretty conservative in some aspects while taking some winning formulas from other areas and bringing into the Class 40.

 

I think some of you just got scared over the Black renderings..

post-55590-0-28468700-1379076522_thumb.jpg

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Yeah, I saw that too. It is still a boat that floats with front sails and back sails.. Not too different...

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Yeah, I saw that too. It is still a boat that floats with front sails and back sails.. Not too different...

I was at the Southampton Boat Show last weekend and the new Ker Class 40 was parked in front of the Caterham sponsored class 40. It was hard to believe they were built to the same rule. Looked very much lower to the water. an impressive piece of kit. Wasn't aware that the sprits on class 40's could be pivoted to windward. Cool idea.

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I sure hope the class defines the freeboard rule as having the deck attached to the gunnel. I like pushing rules to the limit, but it should be the intent of the limit, rather than the literal interpretation of the rule. Change the rule and this thing is dead. Live by the rule, die by the rule.

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Reports are that the boat sails like a dream, very light helm, lots of directional stability at any angle of heel. I never would have guessed that!

 

Squall says: "Why was there an average freeboard rule in the beginning? To create safe offshore going boats.

I stronghly doubt the Ker40 is such a boat."

 

If I was still standing in the 70's, I would say none of these VO70, Open 60, Minis, or Open 40s could be considered safe offshore going boats. But in fact, these full forms -- perhaps objectionable to the traditional eye -- have clearly proven to be very capable offshore boats.

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Big difference for crewed boat ie the 70's, You have a whole watch on deck so 5 or 6 good guys around you all the time to run the boat and keep an eye on each other. This boat looks insanely unsafe but I wouldn't be saying no if I was asked to sail.

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1403490_10151664310412064_1629472023_o.j1399190_10151664308352064_909549860_o.jp

She's looking good and sails well apparently. Love to see how she stacks up against the other 40s in the TJV.

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1403490_10151664310412064_1629472023_o.j1399190_10151664308352064_909549860_o.jp

She's looking good and sails well apparently. Love to see how she stacks up against the other 40s in the TJV.

Zipper reef kite :o

A bearhead sail change then. A nice idea, I suppose!

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1403490_10151664310412064_1629472023_o.j1399190_10151664308352064_909549860_o.jp

She's looking good and sails well apparently. Love to see how she stacks up against the other 40s in the TJV.

Nope still FUGLY.

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Sam and Ned made it to Le Havre this morning, for the start of the TJV.

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Zipper reef kite :o

Class sail limits of 8, including storm sails.

You beat me to it, quite popular in quite a few of the French dominated fleets with similar restrictions as well I think.

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Zipper reef kite :o

 

Class sail limits of 8, including storm sails.

So in theory would that be :

Main

Trysail

Storm Jib

Mo

Fro

J1-J3 reefable

A2-A4 reefable

A5/A6 ? Just assuming heavier weather kites.

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http://www.class40.com/modules/kameleon/upload/jauge2013.pdf

 

 

103.01- dispositions générales
Le nombre total de voiles embarquées est limité à 8. Parmi ces 8 voiles maximum, les bateaux doivent embarquer obligatoirement les voiles suivantes :
1 Grand Voile, 1 Solent, 1 foc de gros temps, 1 tourmentin et 1 voile de cape si la Grand Voile n’a pas son guindant réduit de + de 70% au bas ris.
Seules les voiles déclarées au départ peuvent servir durant une course. Tous les matériaux autres que le Nylon sont interdits dans la fabrication des spinnakers (est considéré comme spinnaker toute voile d’avant dont le SMG est supérieur à 0.75 x Bordure). Tous les matériaux autres que le polyester tissé ou laminé (module inférieur à 300g/denier) sont interdits dans la fabrication des autres voiles, à l’exception de 2 voiles dont le matériau est libre. La grand-voile doit arborer le sigle de la Class40 à se procurer exclusivement auprès de la Class40. Les lattes et boîtiers de latte en carbone sont interdits.
103.02- Définitions des voiles
103.02.01 Grand voile Voile fixée sur l’arrière du mât
103.02.02 Solent Voile triangulaire établie sur l’étai avant fixe. Le solent ne peut pas être construit avec un guindant structurel.
103.02.03 Foc de gros temps Voile d’avant triangulaire dont la surface est limitée à 32 m² (surface = guindant*LP/2). Une prise de ris est possible dans cette voile. Cette voile, conçue pour faire du près dans du mauvais temps doit être réalisée avec un grammage minimum de 8oz.
103.02.04 Tourmentin Voile d’avant selon les spécifications les RSO 4.26.4.e
103.02.06 Voile de cape Voile de brise selon les spécifications des RSO. La voile de cape doit être dans un tissu d’un grammage minimum de 9oz.

 

So: required sails:

Mainsail, Solent jib, Heavy Weather jib (may have a reef. Max area 32 sq m), Storm jib, trysail (if the mainsail doesn't have a last reef of 70% of luff length).

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http://www.class40.com/modules/kameleon/upload/jauge2013.pdf

 

 

103.01- dispositions générales
Le nombre total de voiles embarquées est limité à 8. Parmi ces 8 voiles maximum, les bateaux doivent embarquer obligatoirement les voiles suivantes :
1 Grand Voile, 1 Solent, 1 foc de gros temps, 1 tourmentin et 1 voile de cape si la Grand Voile n’a pas son guindant réduit de + de 70% au bas ris.
Seules les voiles déclarées au départ peuvent servir durant une course. Tous les matériaux autres que le Nylon sont interdits dans la fabrication des spinnakers (est considéré comme spinnaker toute voile d’avant dont le SMG est supérieur à 0.75 x Bordure). Tous les matériaux autres que le polyester tissé ou laminé (module inférieur à 300g/denier) sont interdits dans la fabrication des autres voiles, à l’exception de 2 voiles dont le matériau est libre. La grand-voile doit arborer le sigle de la Class40 à se procurer exclusivement auprès de la Class40. Les lattes et boîtiers de latte en carbone sont interdits.
103.02- Définitions des voiles
103.02.01 Grand voile Voile fixée sur l’arrière du mât
103.02.02 Solent Voile triangulaire établie sur l’étai avant fixe. Le solent ne peut pas être construit avec un guindant structurel.
103.02.03 Foc de gros temps Voile d’avant triangulaire dont la surface est limitée à 32 m² (surface = guindant*LP/2). Une prise de ris est possible dans cette voile. Cette voile, conçue pour faire du près dans du mauvais temps doit être réalisée avec un grammage minimum de 8oz.
103.02.04 Tourmentin Voile d’avant selon les spécifications les RSO 4.26.4.e
103.02.06 Voile de cape Voile de brise selon les spécifications des RSO. La voile de cape doit être dans un tissu d’un grammage minimum de 9oz.

 

So: required sails:

Mainsail, Solent jib, Heavy Weather jib (may have a reef. Max area 32 sq m), Storm jib, trysail (if the mainsail doesn't have a last reef of 70% of luff length).

Oh right.

So that leaves a fair amount of other sails to play with.

Still cool

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Keel system? It's not canting so not sure what you mean.

 

Boat looks alot more minimal inside than alot of the other class 40s I've seen- wonder what the guage is there for?

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With technology borrowed from the America’s Cup, Concise was constructed using a keel tower and V-Straps. Instead of being bolted to the bottom of the boat, the keel structure comes up inside the boat through a tower to the deck. V-Straps built into the hull run from the keel to the chainplates.'

 

Said keel system. Very interesting!

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Keel system? It's not canting so not sure what you mean.

 

Boat looks alot more minimal inside than alot of the other class 40s I've seen- wonder what the guage is there for?

Tacho for the motor which is underneath it

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I don't see the benefit - more material in the boat, more weight? I can't see any bolts on deck - how do they hold the keel in place? The two fat straps running from the bottom of the keel box to the chainplates are just for reinforcement of the whole structure?

 

 

With technology borrowed from the America’s Cup, Concise was constructed using a keel tower and V-Straps. Instead of being bolted to the bottom of the boat, the keel structure comes up inside the boat through a tower to the deck. V-Straps built into the hull run from the keel to the chainplates.'

 

Said keel system. Very interesting!

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Disclaimer: I know exactly nothing about this type of design.

 

It would make sense to me if those straps were put in place to stiffen the structure, putting the forces from the rig directly into the keel and bulb, therefore having a more efficient righting moment, as there is no flex lost through the hull and chainplate structures?

 

Might also be able to make the boat lighter; taking some of the material out of the keel box area along with parts of the hull, because the load is directly transferred to the rig?

 

Be pretty cool to get an informed walk-through of the boat.

 

I also love how you can see the sheets of foam right through the epoxy on the inside :lol:

 

HW

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So they retired from the TJV? What happened?

 

EDIT: OK, so I should have read the yachtworld article:

 

"‘Concise 8′ with Ned Collier Wakefield and Sam Goodchild on board, was one of 26 Class 40s racing 5,400 miles across the Atlantic in the Transat Jaques Vabre. However, with the boat speeding along at 17 knots, the active rudder kicked up and the boat broached. The team led a spirited recovery in the confused seas but a big breaking wave hit the yacht causing further damage to the steering system, forcing ‘Concise 8′ to retire."

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