Kuka Light - Less is More

[STYacht.com]

Hi all,

Decided to start a thread to share some info and find out what kind of response the boat is finding in the Forums. One of the is that we are going to be presenting the boat in a few venues in the off season. First off is a short presentation at METS 2012 where Mitch Booth, multihull champion and helmsman of the boat, will discuss the cross overs between his multi experiences and Kuka Light.

http://www.kuka-light.com

http://www.marstrom.com/index.php?option=com_content&view=article&id=297:kuka-light-review-on-blurse&catid=84:news-spars-monohull&Itemid=72

In preparing data for the presentations, the similarity to the lightest of the IMOCA fleet (PRB) became pretty apparent. If you are able to join us in Amsterdam, we are going to be probing a bit deeper into the project.

The results of the boat in the two main regattas this season (both of which were exceedingly light air) don't do it justice. Really looking forward to pushing the concept even further.

 

[STYacht.com]

I forgot, please use FB to sign up for the free presentation: https://www.facebook.com/events/198460326956458/

 

[STYacht.com]

Getting of few of the simplified graphic comparisons together for this presentation. I thought it might be noteworthy to show how Kuka Light stacks up against some other boats. How light is light, how wide is wide, etc? For the following charts, a few bookends were normalized to the same LWL as Kuka. The notation is therefore: VOR42 for a 42' version of the VOR70, VO42OD for a 42' version of the new VO65OD, AC42 for a 42' version of the AC45, etc. For the IMOCA data, three current boats were averaged (one VPLP/Verdier, one OCDG, one JuanK). I make no claims about the accuracy of the data of the IMOCA's.







At the presentation there will be more such comparisons available, this is a sample.

 

[pogen]

This is such a cool boat. Can you say what the cost comparison might be if it were in production? Way out of my league, but nice to think about.

I have seen some nice pieces about it on BLUR I think.

 

[Blur]

I have seen some nice pieces about it on BLUR I think.

http://www.blur.se/2...eet-kuka-light/

Definitely sweet. But tough work to get the full potential out

of for a "normal" crew. Kudos for doing it.

 

[STYacht.com]

This is such a cool boat. Can you say what the cost comparison might be if it were in production? Way out of my league, but nice to think about.

I have seen some nice pieces about it on BLUR I think.

Thanks Pogen,

The thing about Kuka Light is there were very few discussions about the costs. Crazy, right? The owner was definitely focused on what he wanted, and we prioritized the weight over most everything. We used fibre that you normally would not, Kevlar Nomex which you might, but not if you were concerned about getting the bottom line under control. We built a carbon fin for the keel. Everything done in the autoclave, which has its price as well.

That is not to say we favored weight to strength without a thought. Aside, I chatted with Mitch yesterday, who just delivered the boat back from Malta to northern Italy. He quoted 40+ knots and 6m seas. Crazy! But he seemed pretty nonchalant hosing the boat down and putting her to bed. That said, she has yet to race in that wind. The structural arrangement has adequate frames from the standpoint of number and size. She's tough. Now that the mast is sorted, it is tough too.

The upside is that we have really solid female moulds for everything on board. That is the way you must work in the autoclave. I think that if we were to build the boat again, in the moulds, with conventional nomex, standard high strength carbon prepregs and a steel fin, we could probably produce the boat for 550k-600k Euro. It is a guess, and pretty much the cost of the competition in HPR. There would be a weight change, but it is manageable.

 

[bladerunnerSWE]

to what extent are you trimming the mast under way? are you only rotating it or are you tilting it up to wind aswell? what does the running rigging look like?

best regards

Dag

 

[STYacht.com]

to what extent are you trimming the mast under way? are you only rotating it or are you tilting it up to wind aswell? what does the running rigging look like?

best regards

Dag

Hi Dag,

so, I have to assume you mean mast cant and not rake. We have all lashed standing rigging (top and bottom) and we do not move the rake or cant while underway. Not yet anyway. We have done some studies with the effectiveness of cant, combined in fact with higher angle keel cants (like ... wait for it ... Speeddream) but opted against this, not because the gains were not there, but because of complexity. It can still be revisited. Rotation of the mast is achieved through three sets of small tackle. It is both limited as with any cat rig (pulled toward CL), but also induced, due to the relatively low boom compression compared to mast compression.

The running rigging is pretty straightforward. Perhaps more than I would like, personally. The owner was very set against running anything below decks in tubes. He simply wants to see everything that is going on. For the solent we have a floating ring type lead (common on Class 40). All headsail sheets are cross sheeted always. Halyards all locked except Solent, due to reef. Tack lines all jammed on deck. Lots of lashed rings and few blocks. The main is trimmed like an X40 cat - full beam trav to winch and a hydraulic sheet, no vang. If you sail cats, no need to explain. If you sail most monos, think of the sheet on this boat like a vang - in charge of leach tension. Think of the trav like a sheet - in charge of angle of boom. We have a set of runners (now at topmast) and are experimenting with deflectors in the off season.

 

[left hook]

Just want to chime in and commend you in making the coolest, sexiest, fastest looking oats out there. It's truly so complex and awesome that I am in awe of the skills required to sail it to it's full potential, which, when realized, should be a force to be reckoned with.

 

[STYacht.com]

Just want to chime in and commend you in making the coolest, sexiest, fastest looking oats out there. It's truly so complex and awesome that I am in awe of the skills required to sail it to it's full potential, which, when realized, should be a force to be reckoned with.

Your endorsement noted, but I want to qualify your statement just a bit. The boat is not that complicated, it is easy to make go fast. How could it not be? Helming is not a big effort, not that I have helmed for hours and days. The loads are not great, because the boat is so light, and not that big overall. It is powerful, but remember there are guys going alone around the world on 60' that are probably more powerful (in raw area terms) and nearly as light for their (2.5x larger) size.

Kuka sails with 6 crew - half that of boats her length. Yes, to get the maximum performance, it is very good to have experienced IMOCA, F20, X40, and/or VOR sailors on board, but I don't think that is due to complexity. They don't have to learn apparent wind sailing, and know immediately how to move weight and change sails. Most of the variables are set when the boat leaves the dock. If the keel system goes out, oh my, that is a problem, but otherwise, it is sailing.

Hard not to smile when you are chewing up the miles.

 

[bladerunnerSWE]

Thanks for the reply! It's hard to workout all the details from the few pictures that are available. It's interesting because I haven't seen a wingmast on a monohull in the class (30-40'). We currently own and run a hydrofoil,wingmast tri ( http://sphotos-e.ak.fbcdn.net/hphotos-ak-prn1/39023_475531943867_3439862_n.jpg ) and are looking to implement as much as possible of what we've learnt into a monohull project in a couple of years (around 10m).

While we're on the topic of hightec stuff, what's your thoughts on different variations of DSS and intercept systems? Owen &clarke claim 10-20% less hull drag from their work on the open60 f.x

It wasn't my intention to hijack the thread to this degree, if you want to we can carry this over to pm's and I'll remove this post instead.

Best regards

Dag

 

[STYacht.com]

Hi Dag,

leave your post, because the link is worth it alone. Obviously with all that is going on in Auckland and San Francisco, it is awfully interesting to know what lurks beneath in that photo.

As for DSS, we spoke within the team early on whether this patented system was of interest for Kuka Light. The net outcome was no, it did not fit this project. We have raced against the Infiinti 30 in P2MC race, and the boat certainly seemed quick for her size. I understand the concept fully, but have not tried to crack into the details (after all, it is patented). Seems like an idea that continues to improve.

And as for the interceptor, or trim tabs in general, we did really see the point. We did some CFD work in a seaway early in the hull design, to settle the rocker question. We were not prepared to invest the amount of time it would take to get the gains that more variation in after section effects might provide. I don't know if I buy 10-20% less hull drag, at first glance. Maybe I have not paid precise enough attention, but have interceptors become standard in the latest IMOCA generation?

 

[bladerunnerSWE]

It's indeed interesting times for foil tech. On the subject of infiniti's dss, we have a few ideas and from a glance I -think- we can make a better foil.

To be honest I haven't paid interceptors any attention until I heard about it in

the other day. According to Mike Golding he's the only one still using it. With the extraordinary claims and real boat testing it should get more attention.
You've designed a beautiful boat and I'm looking forward to the presentation, assuming that it'll be streamed/youtubed ofc.

 

[Blur]

The word is that they had a hard time upwind in Middle Sea race, even compared to some of the Class 40. I guess it's not an easy boat upwind in a blow and choppy sea.

 

[STYacht.com]

It's indeed interesting times for foil tech. On the subject of infiniti's dss, we have a few ideas and from a glance I -think- we can make a better foil.

To be honest I haven't paid interceptors any attention until I heard about it in

It is not planned to be streamed. I can ask the organizers or Mr. Clean if he can do anything to change that.

I am also hoping to present something similar in Sweden for the WYRF and the YRDTS. That will depend on the organization if we can be added to the program.

Cheers,

Doug

 

[STYacht.com]

The word is that they had a hard time upwind in Middle Sea race, even compared to some of the Class 40. I guess it's not an easy boat upwind in a blow and choppy sea.

Upwind is not the ideal angle for Kuka Light. In the light light upwind, we cannot sail our "rating" which is faster than a boat twice as long. They do not have any trouble with a Class 40 if there are in anything like the same wind. We have the same sail area, same waterline more or less, a lot less weight, less wetted surface and far more efficient foils. If in the MSR they saw a Class 40 catch up to them, it was due to lack of wind and current. Maybe just sailing to the wrong side of the course. Stopped is stopped, whether 40' or 100'. In the MSR there was definitely no "blow" and only leftover chop very early on.

 

[hughw]

And as for the interceptor, or trim tabs in general, we did really see the point. We did some CFD work in a seaway early in the hull design, to settle the rocker question. We were not prepared to invest the amount of time it would take to get the gains that more variation in after section effects might provide. I don't know if I buy 10-20% less hull drag, at first glance. Maybe I have not paid precise enough attention, but have interceptors become standard in the latest IMOCA generation?

----------------

Can add a bit to this - I put trim tabs onto the Bols 93' back in 2002 having run the idea in the tank, and in practice then there were certainly times we saw 10% speed gain - and that was extremely quantifiable as we were in dead flat water on the lee side of Sjaelland, boat speed 20-24 knots steady, and the tabs would put on a full couple of knots as we flattened out the running angle.

I would guess the 10-20% figure of total hull drag though is a bit optimistic! Interceptors do work well but have a min speed before they become effective in the total drag tradeoffs, tabs are a bit more flexible in that respect.

 

[Blur]

The word is that they had a hard time upwind in Middle Sea race, even compared to some of the Class 40. I guess it's not an easy boat upwind in a blow and choppy sea.

Upwind is not the ideal angle for Kuka Light. In the light light upwind, we cannot sail our "rating" which is faster than a boat twice as long. They do not have any trouble with a Class 40 if there are in anything like the same wind. We have the same sail area, same waterline more or less, a lot less weight, less wetted surface and far more efficient foils. If in the MSR they saw a Class 40 catch up to them, it was due to lack of wind and current. Maybe just sailing to the wrong side of the course. Stopped is stopped, whether 40' or 100'. In the MSR there was definitely no "blow" and only leftover chop very early on.

Some shots from another competitor. Both Akilaria 40 och Pogo 40 were "notably faster" in those conditions. Same wind + track.

Naturally this is not what the boat is buit for, but it affects the time around the course. On elapsed time Kuka Light was equal with Marten 49, Welbourne 46 and Ker 51 - boats that should be beaten by a fair margin. I put this down to crew experience, but naturally every design have som s´weak spots that need to be managed and minimized.

 

[Team_EvoLv]

The word is that they had a hard time upwind in Middle Sea race, even compared to some of the Class 40. I guess it's not an easy boat upwind in a blow and choppy sea.

Upwind is not the ideal angle for Kuka Light. In the light light upwind, we cannot sail our "rating" which is faster than a boat twice as long. They do not have any trouble with a Class 40 if there are in anything like the same wind. We have the same sail area, same waterline more or less, a lot less weight, less wetted surface and far more efficient foils. If in the MSR they saw a Class 40 catch up to them, it was due to lack of wind and current. Maybe just sailing to the wrong side of the course. Stopped is stopped, whether 40' or 100'. In the MSR there was definitely no "blow" and only leftover chop very early on.

Some shots from another competitor. Both Akilaria 40 och Pogo 40 were "notably faster" in those conditions. Same wind + track.

Naturally this is not what the boat is buit for, but it affects the time around the course. On elapsed time Kuka Light was equal with Marten 49, Welbourne 46 and Ker 51 - boats that should be beaten by a fair margin. I put this down to crew experience, but naturally every design have som s´weak spots that need to be managed and minimized.

Good to see the arm chair admiralty has arrived! Children should never see things half done. Move along Blur, you're out of your depth