Wave-Piercing, Pitching damping or marketing?

[Retired Geek]

here's a couple of video's of the boat out practicing today

http://www.youtube.com/watch?v=MRdBQY8YHj0
RG

[patrik111]

Nice to see modelling followed through!

Originally Posted by Retired Geek

Yes, its an A-Class, core is corecell with carbon inner and outer skins, weighs about 34 kg as shown before paint, boards are very high AR (just 140mm chord and draw about 1.15m), rudders are just shorter versions of the boards.

Some specific questions regarding your building method
Is this weight achieved with hand layup and vacuum? Or is it infused?

Heatformed in a female mold? If so, how did you make shure to avoid leaks from the heatforming? (screws from outside but not through?). Have you managed to scarf join the corecell sheets? or did you manage to find Very long sheets?

Very impressive project!

All the best

Patrik

[Retired Geek]

Originally Posted by patrik111

Nice to see modelling followed through!




Some specific questions regarding your building method
Is this weight achieved with hand layup and vacuum? Or is it infused?

Heatformed in a female mold? If so, how did you make shure to avoid leaks from the heatforming? (screws from outside but not through?). Have you managed to scarf join the corecell sheets? or did you manage to find Very long sheets?

Very impressive project!

All the best

Patrik

Hi Patrik,
boat was strip planked and hand layed with a vacuum, attached pic shows the strips used....other than that all credit goes to Ian & John for doing a brilliant job
RG

[TTS]

The second LR2 on it's first sail with Fred smiling on the helm.Way to go Fred! Great scenery too. Tom

[DSmith]

Originally Posted by Retired Geek

Hi Daniel,
your right about the lump on the end of the trapeze, and their may be some sort of advantage to clothing similar to what downhill skiers use, but I doubt that it will change your uphill VMG that much.
RG

I would have throught that it would have made a bit of a difference to windward where you have the highest apparent wind speed and your VMG depends on the overall lift to drag ratio. It always surprises me to see the amount of aero drag from the crew and hulls that comes out of the VPP.

[TTS]

Just a reminder to everyone! The new Roake/Lindahl LR2 will be racing at the lake Hoptacong A-Class fall regatta on Sept. 28-30. There will also be an on/off the water seminar put on by current NA champion Lars Guck. This should be a great clinic and an interesting and fun regatta. There will be two new designs at the regatta. Ian Lindahl and Fred Smith's new LR2 as well as the new Ben Hall/Peter Cogan designed A-class featuring a rigid wing sail. John Lindahl is the primary builder of the LR2 with assistance from his son Ian. John has been a builder for over 25 years and has built a few A's in his time. He has extensive building experience from Melges Boatworks to his own designs and many more. the molds for the new Hall/Cogan design were built at Vectorworks marine in Florida, but I am not sure who built the boats themselves. I will try to get this information. There currently are two of these boats on the water. Ban Hall of Hall Spars is the driving force behind this new project and is one of the stalwarts of the A-Class. So to round it up, there should be 2 LR2's and 2 Hall/Cogans at the regatta. If you are anywhere near the area, it should prove to be an exciting and informative weekend.

Tom Siders

[TTS]

Some Lake Hopatcong Pictues from LesBurn on catsailor.com.
http://mysite.verizon.net/vze28w8n/

[Retired Geek]

As predicted, it was very shifty at Lake Hopatcong so I doubt you can read much into any individual boats performance.
Finals places were 1st, Lars Gluck, 2nd, Ian Lindahl tied with Michael Gruber
RG

[TTS]

Since RG has not yet updated this thread here is his news. There will be three LR2s at the 2007 ronstan A-cat Worlds. Ian Lindahl will sail hull number three, Fred Smith on hull number two and for the real news here, Randy Smyth will be on hull number one. Randy will also be bringing newly designed and "radical" sails to the event. This should add some spice to what is already turning out to be an exciting event and a great place to debut a new platform on the world wide stage.

[Retired Geek]

Originally Posted by TTS

Randy will also be bringing newly designed and "radical" sails to the event.

I'm not sure radical is the right description, but it is different from the current crop of competitive sails that are available.

Attached pic is boat #3 in primer, will post some sailing pics tomorrow.
RG

[TTS]

The beams are imbeded on this one without the little stub ends hanging out. boat looks great RG.

[Retired Geek]

Tom....you missed the fact that the whole of the hull fwd of the front beam has been changed slightly, less volume and waterplane area. Had to get rid of a little excess lift we had (see below).

ygyssdsy...for a conventional wave piercer you'd be correct, but what if you could have a variable radius of gyration ? and the damping effects were dynamic and not static ?

Attached a couple of pics of Ian (approx 1 sec apart) out practising a few weeks back, where he came up a bit too high looking for speed, the gust hit, bows go down and then our design comes into its own and spits the bow out....all in around 1 sec....note....no significant waves to help or hinder the process
RG

[PI Design]

Can anyone describe the Smythe sail?

[Retired Geek]

Here's a couple of pics from Boat #3's first sail
RG

[bobdarbygso]

RG, TTS, Steve Hall

Having had time to digest the lessons of the A-Cat worlds, can you comment on the performance of the various new designs (LR-2, DK-17, Ben Hall's new hull, etc.) versus more "traditional" hulls, trying to factor out differences in rigs and crews?

Thx,
Bob