NACRA 20 with Lifting Foils!

[Doug Lord]

First production "beachcat" with "foil assist" using curved daggerboards(banana boards)-very interesting. Stealth 16 (I think) was first or second in using rudder t-foils.

http://www.nacra.ca/images/stories/i...finalsmall.jpg

Press Release - 16-10-2009 – for immediate release

Nacra is proud to announce the upcoming launch of its new flagship, the NACRA F20 Carbon. This latest addition to the Nacra range is a new high performance 20 ft catamaran.

Peter Vink, head of the development team: “ The whole development team is very proud to share the first information about the new Nacra F20 Carbon. We have been working with the best-of-the best in the maritime industry to ensure that this is truly a “king of the beach” boat. It will be bigger, wider and faster than anything in-or outside its class”. Although nicknamed “Babyzilla” by the team, it will still be a boat that can be sailed by the local club racer and be able to win at it’s first outing at the club race.

Peter Vink:”We took all the best features and characteristics of our current F18 Infusion, which has won the last two F18 Worlds, and applied it to the new boat, as an example: the rudder system, mast extrusion, beams and some other small bits and pieces, this way we have proven technology on the new F20 Carbon”.

The development was done by world renowned designers, Morrelli & Melvin for hulls, Nils Bunkenburg, A cat guru for the foils, Performance Sails for the rig & sails combined with the in-house knowledge at Nacra.

Development and testing has been underway for over 18 months, 2 boats were fitted with both straight daggers and with foils to allow the team to compare; a third boat, a Nacra 20 was fitted with the wide beams and the new rig. The 3 test platforms allowed the development team to test in the real world without revealing to much about this new boat, so they could adjust and fine-tune the design.

A variety in masts, mast hardware positioning and different sail cloth and shapes has been tested. The new hull shape which has been created, starting with a wave piercing bow forming a diamond shape hull stretching backwards into a “square-ish” transom, is of mayor importance due to the combination with the curved daggerboard. Although the basic shape was chosen, several adjustments were made driven by new technology [computer fluid dynamics] and knowledge which was gathered by Melvin & Morrelli while working on the Americas Cup project for BMW ORACLE.

Pete Melvin:”It is not a coincidence that the hull shape of the new F20 Carbon shows resemblance with the floats of the AC boat, we were able to take the knowledge we gained at the AC project and scale it down to the F20 Carbon. The most noticeable and distinctive feature is the chine that runs from the bow backwards on the hull allowing the water to flow away from the hull. Combining the chine and wave piercing bow with the upper deck shape reduces drag piercing through the waves both upwards and downwards”.

Regular production will start any moment and the first boats will be ready to be delivered to the customers in the first months of 2010.
Please see attached document for technical data

[TTS]

Doug,

The Marstrom M20 has been built on a production basis for over a year with c-foils.

[Doug Lord]

Thanks, Tom. I just checked the Marstrom site and (unless I missed it somehow) none of the M20 pictures show curved boards nor is there anything written about it. Do you have a link?

http://www.marstrom.com/index.php?op...m-20&Itemid=67


Just found this: http://www.johncaseyworldwide.com/?p=975

[TTS]

I will look for the link. Some of the original M20's have been retrofitted and I think the c-boards might still be an option when being built. Marstrom makes them for the A-Cat as well. You also have Scheuerer out of Switzerland placing them on the G5. I think that they are also available for the 20 Beaver. ASG is offering them on the latest generation MKII Flyer.

[Doug Lord]

Thanks,Tom...

[Doug Lord]

Here is a rendering from Morelli and Melvin showing the curved foils:

[Sly]

What are the handling characteristics and benefits with curved foils on these boats?

[Doug Lord]

Your best bet is to ask Nacra. There could be a slight reduction in wetted surface and a slight increase in pitch resistance. There could also be a slight reduction in RM since the center of lift of the foil is inboard of the CB of the hull when the windward hull is flying and the windward board retracted.
Curved foils on 60' ORMA tris lift as much as 60% of the total weight -or more- significantly reducing wetted surface of the lee hull(ama) when the other two are flying. These foils, however, do not appear to have the capability of lifting anywhere near as much of the total weight.

[Doug Lord]

Good pix:

(click on image then again)

[DiasDePlaya]

I just found this pic in an Argentinean forum, he is Edoardo Bianchi, an Italian cat champiom, but no mention about the boat.

[Doug Lord]

Apparently he is sailing a boat designed and developed at the University of Genova(Genoa?)-sort of a mini-hydroptere with the same foil configuration:

[SteveMellet]

How much slower do you think it is on foils than it would be if it were sailing ?

[onedream]

The boat in the picture is White Dragons (english translation of the surnames of the two designers Bianchi and Dragoni). They are in fact graduating in nautical engineering in La Spezia University. Bianchi has been an italian olympic crew on Tornado. The cited Professor Edward Canepa which supervise the project, is himself a great catamaran sailor, crew in many campaigns with Stephan Griesmayer (of European and World Hobie Cat fame)and Marcolini. The boat is based on two Bimare V1 A class hulls. Sails and mast come from a Tornado. Transoms, rudders and foils are custom and were built by Riba a carbon fiber italian specialist (Ferrari F1 supplier, by the way). Overall the project, in spite of a very small budget, is proving successfull. First test demonstrate a very good flyng ability with very low wind speed. Actually this is the first promising italian sailing foiler coming from Italy after 30 years oblivion.

[Doug Lord]

Thanks to DiasDePlaya and onedream for the very interesting info on the mini hydroptere-appreciate it!

[Submarine Tom]

Doug,

I concur, outstanding contribution to your thread.

SteveMellet,

Your question is very confusing. Do you mean: How fast on foils compared to on pontoons? I would guess four or five times faster, maybe more!

-Tom