NACRA 17 Olympic

 

Here in sunny Singapore

We are extremely excited that the N17 has won the Olympic multihull berth. But we aren't the only ones excited as we have strong interest in 3 boats so far for Singapore. Unfortunately these orders can not be delivered until January 2013 as the first 100 production N17's have to be sold to National Sailing Bodies in sailing nations around the world. The N17 will be a successful boat in the local sailing environment where traditionally the F16 has been the biggest class. The N17 with its curved foils and light weight will add a new dimension to cat sailing. 

 

Platforms like the N17 that are light and highly powered provide an exhilarating ride in our conditions where we suffer predominantly light winds year round! You control the speed of the boat by adjusting how much lift you generate. You control the lift by trimming your crew weight fore and aft! More aft trim gives the foils a positive angle of attack. More positive means more lift... When you start to go fast it might require small adjustments to weight forward to get the foils level so that drag can be reduced and speed can increase - interesting enough!

 

Nacra submitted two multihulls to the Olympic Trials, the Nacra F16 and the Nacra 17. Although the F16 met most of the ISAF criteria, the Nacra F17 was specially developed from a clean sheet to specifically meet the ISAF criteria. This meant that the new Class would not intrude on any established class in the world - clean design in every sense!

For the design the Nacra team followed a familiar path to the design studio of Morrelli & Melvin from Huntington Beach, California. 

 

Morrelli & Melvin are known for their America’s Cup development and many other successful multihulls projects such as: PlayStation, Gunboats and of course Pete Melvin won an A-Class World Title onboard one of his own designs that was for a period, manufactured as the Nacra A Cat.

 

Early on it was decided that the new Olympic contender should have curved foils. This stemmed from the fact that Nacra had already amassed production experience in beach cats with curved foils. It would also have to be wave piercing, light weight, robust and fast!

 

Wave piercing designs tend to 'drill' through waves with a far reduced pitching motion. This allows the sail generated power to be deployed more consistently for greater performance. 

 

The Nacra 17 and the Nacra F16 are the stiffest production platforms available in their respective classes. THis resulted from the experience of the super wide Nacra 20 Carbon and buy using advanced beam design as well as wide beam landing sections to distribute the racking loads better. A direct result of this work is that  maximum energy is transferred into forward motion.

 

The necessity of curved foils came from the N20C program that showed that curved foils offer, much better control over  the boat in windy conditions while being less crew weight critical and allows for mixed crew combinations.

 

'Clinical tests' show that curved foils,

 

  • Lift the leeward hull out of the water thereby reducing drag significantly and increasing speed

  • Generates lifting power to fly the hull earlier and gets people on the trapeze wire in lower wind ranges

  • Nacra's Carbon platforms like the N16, N17 N20C are strongly built in epoxy/glass and Carbon that results in a durable and robust structure that is also agile to sail.

 

A modern rig is essential and the N17 utilizes a two-piece carbon mast to gain performance while increasing the portability of the design and reducing the tip weight for easier uprighting. The wing section is supple and is easily controlled during moments of de-powering.

 

The Nacra 17 won the Olympic selection trials for a number of reason that included "thrilling to sail". The trials saw the new Nacra F16 and the Nacra 17 competing for the same arena. In the end the result is a good one as the N17 is a "clean sheet" and her inclusion into the Olympics will not detract from any established class. The mixed crew format is going to make this arena a very interesting one!

 

 

 

 

SPECIFICATION
Hull Length 5.25 m
Beam 2.59 m
Mast Length 9.00 m
Total upwind sail area 20.10 m2
Spi Area 19.00 m2
Average crew weight ±135 kg
Overall weight excl. sails 138 kg

 

Foil borne cats like the N17 and N20 represent the new wave of sailing and are amongst a few cats where you trim weight forward to go fast! Remember when you couldn't get far enough back!! In the photo above you can see that even in flat water the amount of lift being generated by the foils lifts the bow clean out of the water.

 

The foils are asymmetric and as such, you need to lift the windward board to obtain as much windward ability as possible. Leaving both down well, the leeward lateral component from the windward board will tend to cancel the windward lateral component of the leeward foil.

 

Downwind this is not such a big deal... But definitely upwind one has to be raised. The other rule with boards/foils... As the downhaul comes on the boards come up!

 

Now, go practice...

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