What I want to know now that we have some saying it is fast as well as looking fast is how RG made it so? Is one thing to call it a wave piercer, but what have they done to make it so clearly efficient? how are we to understand what the improvement is if we can't say what has made the differences? Between everyone here, there should be some who can give us some insight into whats been achieved here and how, no ? Doesn't do us much good if we can't understand it all other than to say it's fast
Q

Who is to say that the performance improvement (if achieved at all) was the result of the hulls ?

I see more then a few things on this design that have been changed. Extremely narrow daggerboards and rudders is one example.

Basically, what we have now are striking claims of improvements but hardly any info/proof to do a thorough investigation of the situation.

Personally I think an improvement of 2 knots on the upwind VMG to be suspiciously large. That is a 20% improvement and I find that very hard to attribute that to the hulls, knowing that wave-making drag is only some 10% of the overall drag. Additionally, considering the state of performance of modern A-cats I think any sudden 20% improvement claim to beyond believe.

I think it took the combined effort of all the A-cat designers and 30 years to make the modern A-cat less then 20% faster then the uni-corn (predecessor of A-cats) and that included making the sail area larger and the boat lighter.

Sorry guys, what you guys doing is very interesting but I need much more convincing.

Wouter

Wouter, while Im only a merchant banker with a strong interest in sailing, I do however spend most of my time financing offshore oil related projects, and quite often see cutting edge R&D that shows 20-40% gains that are fluid based gains, hence the questions. As a lay observer and not a designer, I have yet to see another cat that has what the LR2 has appeared to achieve and has people other than the designer willing to back it, from my perspective, its a rather bankable assumption (forgive the pun)
In my line of work, I question all the time in order to understand and reduce the risk, so Wouter, backing it by precedent is just making noise with no real attempt to justify any real knowledge, you either know or guess at the gain or you absolutely dispprove it with fact, so far I have seen neither argument here.
Q

also forgot to mention the best polar showed approx 9 knot vmg, +2 =11, that to me is interesting territory
Q

Let me put the problem in financial terms for you.

How can you achieve a cost reduction of say 20 euro's when the total initial costs were only 10 euro's to begin with ?

With respect to my supplied data :

The 10 % wave-making drag quote comes of the C-class miss Nylex research article. This component will be lower for our soft sail boats as Miss Nylex had a much more efficient solid wing sail. Sail induced drag is actually the largest single drag component in the overall picture. By having less of it you lower the total drag and thus relatively increase the importance of the smaller components.

With respect to offshore oil experience. We are designing sailboats here not pipelines.
In the latter fluid behaviour is nearly 100% of the whole proces. With sailboats (hulls) it is only 5-15% of the whole picture.

Wouter

(I'm a combined Mechanical/Maritime engineer, in Holland these two programs are combined at the university level)

Well now one of the points of this build was to reduce the overall cost of a competitive A-Class boat. In US dollars a new A is @ $30,000 Marstrom, $26,500 Geltek Flyer, $24,500 M&M A3, 25,000 Bimare XJ, $23,500 The Tool, $26,000 Scheurer G5 and the LR2 20,000-21,000 depending up the rig. This does not state that the final cost of the boat will not end up more than that, it just was one of the initial goals. As to final pricing that would come from John and Ian Lindahl. Now that they have 2 boats completed and the third on the way, I think they have worked out the labor and material costs so as to be able to know what the price point needs to be to remain viable.

As to performance, the boat has so far sailed well. The learning curve has been steep, but I think the next regatta at Lake Hoptacong on 9-28/9-29 will allow the boat to sail against around 40 other A's. This should be an event where the boat can begin to show what it has and can do. I believe that a strong contingent from the Bristol fleet will be there as well.

Why don't I add this to the thread as well!

Peter Cogan designed a new A cat. It is a very nice looking evolution of the current theme, IE flyer/XJ/A2



Ben has one of the first two built, to my knowledge. Vectorworks built the hulls and molds for Peter.



I am not privy to the plans for this boat but would expect it to be offered for sale by someone.



Ben has also built a wing sail. Doesn’t seem real practical, we’ll have to see where it goes. I don’t think anyone else is interested in building one. I can’t see Ben letting it kill the class he has supported for so long.

Yes. but Wouter has a keen eye as well as you....and he sees what other do not and says it will be a dog in anyting but flat water.
I can make no conclusions as Wouter has also pointed out my mental retardation which stops me from making a rational judgement.
Do tell us more about why it will be such a dog in the rough Wout, I am hanging on every word....or is it just that the small rudder and daggers make a boat fast in chop?
Small words for me please Wouter as I am trying to keep up.

All my comments made at the time of writing are based on the understanding of the LR2 that I have at that time. As we all know, information is dripping out continiously and as such my understanding of it develops with it. However up till now not much info has been forth coming; so my understanding may well be strenious.

But to answer your questions Warbird.



At that time of commenting I didn't see anything, mostly I missed bow height. What I've learned from sailing other catamaran designs is that a low bow height makes sailing in rough watersurface conditions challenging. With rough I mean waves combined with a chop on top. Even with the very rounded decks on the F16's we found that it is best to not have water hit the decks. When it does a few things start happening that will hold you back. Rounded decks are indeed much better then the square decks of older designs like the Prindle 19 and Hobie Tiger but the improvements only go so far.

If this lowering of the decks coincided with a reduction in bow bouyancy then the result can be worse still, think of the Bim 18HT in rough conditions. Nobody likes the design there.

The A's are increasingly cutting away their bows. All other high performance (development) boats that sail often in rough conditions like the F18 and F16's are going exactly the opposite direction. They are increasing the bow height (although not really adding volume there). I find it very interesting that the two designs go directly opposing routes. On the other hand it has become a rare sight to see A-cats along the coastline were I sail.

So what goes wrong with low bow on other designs ?

Running starts running up the decks at speed and hits the beams. When the beams are not well faired into the hulls then this will send a thud through the whole craft and may even initiate a dive upwind. I see the LR2 has the beams actually sticking out the sides of the hulls. The modern bows resist pitching well as long as part of the bow is above the waterline. It feel feel firm in gusts and when riding down waves. But as soon as the waterline moves past the deck the feel of firmness deteriorates. It is still much better then the older squared deck hulls but there is a change of feel nevertheless. When they are in it becomes noticeably easier to push them in further. I put this down to the creation of a downforce on the bows because the water it hitting the decks from above and because of the total lifting (displacement) forces can not increase beyond their max value; something that was happening when the decks were still above water. Pretty much at first you experience a hull that shows high resistance to INCREASING the pitch angle followed by a bow that suddenly shows less resistance to INCREASING the pitch angle further. Many crews, among which myself, don't consider this a nice behaviour. Especially in rough conditions it may be difficult to predict/know exactly where this transition point is. The solution is as discribed earlier, increase bow height so this transition happens at much larger pitch angles, hopefully to a level hardly ever encountered. The above experience is reflected in comparing my own Taipan F16 to the Blade F16. The Blade can be pushed harder and sail faster, but my Taipan gives better early warning of approaching the limit. Read back on the Capricorn and Blade reports to see the above behaviour worded in other terms.

I fear that the LR2 will noticeably suffer from this. Mostly because waves initiated this behaviour and up till now the design didn't see any waves in my opinion. Just flat water with some small wind chop on top. Chop is not the same as waves ! Ask Matt McDonald and his experience at the F16 Global Challenge !

Small rudders and daggerboards, What can I say ! We have all been down this road before. These are very nice in stable and relatively flat watersurface conditions. Now try them in rough conditions with significant gusts and waves or even try to hold your position on the start line with them. Pretty much they work in laboratory like conditions but not outside of those.

Maybe the designers of the LR2 have found a different solution to these issues but I'm sceptical. I'll give them full credit when I'm proven wrong, before that time is is just unfounded claims.

Wouter,

There will be a full report of the boat's performance after the Lake Hoptacong regatta on the 28-29 of this month. One of the aspects that has been left out of this convesation is that both Ian and fred are in a learning/discovery stage with the new boat. So while there has been some interesting data to date, detailed in greater amount on the boatdesign forum, than here, it is still early on in the understanding process. I would say to make any conclusions at this point is a bit premature. The early reports are that the boat is handling in a manner that was expected from the boat by the designer. Ian has stated that his learning curve has been quite steep and he tends to load the hulls up sometimes by sheeting too tight among other issues. So far they are driver issues. So why dont we give the critiques a rest as we await more definative information to come out of the upcoming regatta. It also looks like there could be as many as three LR2's at the A-Class Worlds to be held in Islamorado, FL in November. That will be a great showcase for the boat, the helmsman and the class itself. There will be more than one new design and thought process making a debut there. I would estimate that there will be the latest generation of sails from Glaser, Ullman, Ashby, Landenberger, Goodall, Oxo, RacerX and others. there will be at least 4-6 relatively new boats and designs including the LR2, the new Peter Cogan/Ben Hall design, A new Marstrom (wave-piercing), 2-3 new Australian boats, the refined A3 and possibly a couple of one-off designs along with the rest of the existing competitive designs out there. I sail a Boyer MKIV and if my sailing abilities were that of the top 20 I would be able to finish on this boat somewhere in the top 25%. What hampers me more is my own abilities than that of the boat itself. Would my boat win, probably not, but the speed difference between the top boats is incremental.


Tom
just a few pics to show the difference between Ian's boat (red) and a Flyer (green)...pic's are a comparison at full load (i.e sailing on one hull)
RG
Attached Thumbnails


http://www.boatdesign.net/forums/showthread.php?t=18037&goto=newpost

Cool ! Looking forward to it.

Wouter

Bla bla bla Wouter. Your disclaimer does nothing to hide the fact that you think you are a cut above the thought processes of others Wout and the facts show it is no more than unfounded arrogance.
I will stop pulling your wings off now as I am tired of you but the next time you decide to suggest I am a retard, put your brain in gear and turn your computer off.

On triangular courses I'm glad I had those high bows for those wild reaches.
I liked to gauge how hard I am pushing the boat by how many inches the deck was above the surface as a safety factor.
I wonder with Upwind/Downwind courses is reserve buoyancy really needed?

Just perusing USACA, the first LR2 is for sale after Lake Hapatcong, they must be very confident if the sale is only after the results and also begs the question of what changes have been made to boat #3, after all you only build a new one if you have something better in mind, no?
Q

I think that the point is to move the first boat and create cash flow and build more boats. There probably are some small adjustments made to boat # three which you would expect. Find out what you can and need to change and change it. In the A-Class you see quite a few changes in newer boats. The A2 is now on version A3 with Pete and Jeremy having made changes that they feel make the boat better. The Geltek Flyer is also on version MKII or MKIII.

Lake Hoptacong NOR

I know none of you have every done this before... ever right...

Well I guess I got the dates a little messed up in my earlier message. The Race Days are actually September 29th and September 30th. We will be having Lars Gluck do his coaching on Friday September 28th.

Sorry for the confusion.

On another note:

DEBUT of NEW BOAT DESIGNS
So it looks like the group has assembled pretty well for this regatta again. An added bonus this year comes too. We have travelers, Lindahl's, coming from Michigan with a very radical new boat design and it will be doing its first debut of racing on the east coast here in NJ that weekend. We also have travelers coming in from Canada's A-Cat fleet and one of which has one of those new boats also. many of us have heard about this new concept in hulls and now we get to see it up close and on the starting line

I know some of you have also seen Peter Cogans new designed hulls and boat, taking the good parts of the Bimare and Pete Melvin's designs and putting it together in a new hull shape. Should be fun to see the performances of each of these new designs before heading down to the worlds later this fall.

HOUSING ...Going Fast
We are starting to make assignments for the housing for the regatta. Lots of good houses left but with the response we got last week they will fill up fast. So if you are at all interested in coming for the Party/Racing, please let me know ASAP so I can keep a count on the guests and start farming them out to the fleet members. Almost all of us live on the lake front and have accommodations ranging from big private homes to historic boat houses with apartments above them.

FAMILIES WELCOMED
Also consider bringing the wives and kids. We have three families attending so far and we will try and get them close enough, if not in the same home, that there is some self entertainment benefits. Last year a bunch of the "Significant Others" took off on a shopping spry and some went off to New York City while the sailors wee having a great day. The yacht club itself is very friendly with children and has good swimming and food all day as well.

Well hope we can see ya up here at the lake in a couple weeks.

This last post was from the usaca.info emailing that I copied and reposted here. Just want to give the credit to the sender who was not me. I belive it was M. Skeels. Also it should read Lars Guck of GuckInc. (current A-Class North American champion) is giving theon the on/off the water seminar.

Copied from usaca.info website!

9/13/2007 2007 Roake and Lindahl First platform built and has been sailed for 2 months. Has been weighed in and is underweight. Exceptionally stiff platform that can be sold with or without a Hall Spar and Glasier sail or sails. Spare boards and rudders are available also. Could be available 1st of October following the Hopatcong regatta. Contact for pricing.
John Lindahl - jlindahl_lcd@yahoo.com
Ian Lindahl - ian_lindahl@yahoo.com
New A-Class from Roake and Lindahl
There is a new A boat sailing. This probably comes as no surprise to many of you as we haven’t kept it a secret and photos are on the web. The idea of building another boat was generated about a year ago when my son, Ian, thought “we” should build a new boat. The last A I built was 18 years ago and sailed it in the 1988 Worlds. Ian always liked that platform and thought that todays, more powerful rigs could drive it to potential. I had to contact the designer of that boat, Richard Roake, to see if he had any ideas to improve that design. Little did I know he would put all his energy and hours of computer time into a brand new boat. The question was “If I design it will you build it?” My answer was “yes” and we were off and running. The combination of Roakes computer and my epoxy and sandpaper had worked twenty years ago and has worked well again. Ian knew what was good and what was bad from his sailing experience in A boats, 18 squares and a variety of other boats. Dad listened and since we had a brand new design we came up with a very unique build method for the boat. We strip planked a hull shape with 3/8” thick foam. The shape was achieved by using female building frames CNC cut from Roakes design. The shape was carboned with WEST System epoxy and we came out with an exceptionally stiff platform. New boards and rudders were designed and built as well. We used an existing rig of Hall Spars and Glasier sail so we could evaluate the new platform independent of a rig change. So far the performance has exceeded expectations. This boat just feels different underfoot. There is almost no pitch, great stability downwind, and excellent windward VMG. We believe the design premise of a more responsive hull has been achieved. We have built two boats (one has gone to Fred Smith, who gambled with us, right from the beginning) and will have a third built in time for the Worlds.



Contact:
John Lindahl (jlindahl_lcd@yahoo.com)
Ian Lindahl (ian_lindahl@yahoo.com)

LR2 Update

As stated in another thread, the LR2 will be at Lake Hopatcong this weekend. A question was asked earlier in this thread as to what changes would be made in the next boat. It seems that the current LR2 is going to be the full sized hull working well with heavier sailors, the 190# and up range. So the next version/mk will have much less volume and be targeted at the 165# weight range. RG can speak up here for any additional information that he would like to include. It will be great to see the LR2 against the new Hall/Cogan design this weekend. I believe that the LR2 is on the right tract, but lets see what the racing states. I for one want to see how the boat does against all of the other designs that will be present at the regatta. On a different note, great winds on Lake Winnepasaukie, NH today on board a Boyer MKIV 2up. 89 degrees, winds 12-18 and a great sail on the only A-Class on the lake. What "A" Blast. Fair Winds.

Tom,
The current boat has been sailed at up to 285# and it definitely goes faster at that weight and you still can't bury the bow, this is both uphill and down hill and in winds as low as 7 knots so far, below that I don't have data for yet. The rough gain in VMG is about 0.2 knots over sailing at what I had designed as the correct crew weight.
The 3rd boat that Ian will sail at the worlds has a mid range modification to reduce both bouyancy and lift and will be but one of several changes I have in mind and hence is not really a definative Mk2 version, just an evolution from what we have learnt so far.
In rough terms the LR2 has about 8.7% less surface area than a conventional design, boat 3 will be about 9.4% less and the iteration after that as it now stands will be approx 11.5% less, wetted surface area in the same progression is -1.4%, -1.85% and -2.8% and waterplane area is -3.2%, -4.9% and -8.8%. Right now I'd guess that boat 4 will be pretty close to a final configuration assuming that the next one does what we expect it to do.
As for race pace, sometimes the boat sails really well and other times not, I'd say its not yet an easy boat to master, but we are working on that, other than that the races will tell how well we have done.
Other than that I'm quite pleased with what John, Ian and I have achieved so far, considering how far off the beaten track we have strayed :-)
RG