Southern's Foiling Moth rig explained

Nice article copied from Sail-world.com


Southern's Foiling Moth rig explained

''Mr Foiling Moth' Rohan Veal flying with a Southern Spars rig at the 2009 Int Moth Worlds'    Sean Trew (Pacific Fog) ©

During the recent CST Moth Worlds held in Oregon, Southern Spars new rig design was put to the test. Results are in, and 10 of the top 20 competitors were using Southern Spars kit.

So what makes up the Southern Moth rig?

The key objective was to produce a rig that would fit the range of sailor weights now common in the Moth class. After a collaborative R&D effort between Southern Spars and North Sails that included analysing mast stiffness characteristics and current sail designs in the class to the nth degree, it was decided that two spar options would be produced.

Southern Spars developed its two masts: the standard P1 mast suited to all sailors, as well as the aptly named Phatboy mast for the heavier sailor. The rationale for developing two different masts is that larger sailors apply more force through greater righting moment and consequently force masts to bend more than a smaller sailor. Therefore, it made sense to design two masts with different levels of stiffness that would bend equally regardless of the size of the sailor. This evens out the playing field for a larger sailor by allowing them to make better use of a standard sail design.

Both spars are two-piece masts made from high modulus carbon - laminated to give the most consistent bend possible; they are joined with a spigot. The mast plugs are made of lightweight Acetyl plastic, while the spreader attachment is carbon and the stay attachment is a small lightweight alloy fitting – presenting less windage than the previous mast.

The new high modulus oval boom is approximately 25% stiffer than its predecessor making vang changes more decisive; it also offers less windage and weight. The mast package has absolute minimal weight at approximately 2kg fully rigged.

Southern’s Composite Rigging have also developed EC6 carbon stays for the Moth. The new stays are 1.9mm in diameter and weigh just 29g apiece. This is considerably lighter than both PBO and wire rigging, which weigh in at 44g and 128g per stay respectively.


by Brenna Pringle   5:59 AM Thu 15 Oct 2009

Worlds Lessons

So the Moth Worlds are over, I finally have had a chance to take a well deserved rest from Mothing and have started reflecting on what can be done better in my own personal sailing as well as what North Sails can do better for the 2010 worlds.

For me it is simple, more time in the boat is the only way I will be able to compete with the level the class is heading. Clearly speed is not all that is needed to win these days, good starting, good tactics, good boat handling and reliability are all essential. These are the items I will focus on in the next six months in that order. Nothing new to sailing, but defiantly more important in moth sailing than ever before. Maybe I should listen to Dave Lister and stop blogging?

Now onto the sails. Always room for improvement in sails as well. I think overall we have to be very pleased with the way the North Sails performed. Our goal was to have 5 boats in the top ten which was realized. Obviously Nathan won the US Championships and we also had 5 boats in the top ten for the US Champs too.

Below is a list of the gear table I made after the event of the top 30 sailors (Obviously some sailors used multiple gear, but I think this is the best representation of what everyone used):

As with all sailing, the best sailors placed well and I am sure Bora would have been able to win in any boat, mast or sail combo. Unfortunately we did not have our sails on many Mach2's (Only Nige who used our sail from time to time with good effect). Interesting is that the first 9 of 10 Bladeriders used North Sails.

Top 11 Bladeriders

Back to the subject here, what did we learn about making the sails better? It was clear that the stiffer carbon battens are critical, esp as the wind increases. Some sailors used the carbon battens in the top three battens and others used them in the lower battens. I personally used the carbon battens in all of the battens and felt that my sail looked pretty good and matched the Southern Rig well. We will test some new sail shapes, which are a slight modification on the current theme, but taking lessons from the V6 which really seemed to be the best all around performer. North will also spend time looking at how to make the sails more robust without adding weight, esp in the luff sleeve which like all moth sails tends to get hammered rigging up and carrying out to the launch site.

Kevin Hall had a test V10 design which was closer to the V6's molded shape with a reduced luff curve to fit on a super stiff Southern mast, this shape maybe adapted for the stiffer masts anticipated for the worlds in Dubai.

My feeling is that mast development will be where we see the most development going into the next world championships with Southern and CST working on the fine line between light weight, stiff and robust spars. Stiffer masts will be key and of course nobody is going to want to carry heavier rigs or risk failure which will make getting the right amount of off axis carbon dialed perfectly.

Rohan, Bora and Nathan in the US Champs

Kevin Hall leading race 1 of the US Champs

Typical race start at the worlds, short line only the top ten boats had a clear lane, after the start if you did not nail it you had to wait for the top ten boats to clear out before you could put the bow down and send it.

Yours truely yet again overstanding the top mark.

Rohan, Rob, Chris W, Adam and Chris G

Rohan and Nathan leading in the US Champs

Nige proving he still has it, nothing goes better to weather than Nige in 20+ knots!

 Fleet of North Equipped Moths following Bora around the top mark at pace

Of course the most important lesson of all was how cool all the moth sailors are and what a great group of sailors who I can now consider my friends, nice to meet everyone!

Photos from Sean Trew at http://www.pacificfog.net/mothworlds2009/ ubercool guy and I am sure everyone in the moth class appreciates Sean taking time out of his life to document our crazy addiction to share with the world.

Also, thanks to our sponsors, esp CST, Zhik and West Coast sailing. Last but not least to the Columbia Gorge Racing Assosiation and all their volunteers who made for the best ten days of sailing I have had in many years- Thanks!

Stay tuned to see what is going to be the next developments from North Sails and Southern Spars to improve your boats performance.

Sailor Guide

While the gear guides are cool and of course Moth Sailors are "Gear Heads" when you really get down to it, I think the lineup for this years World Championships is what the class should be talking about. While maybe small in numbers the list is pretty impressive in quality, quick Google search came up with the following:

Scott	Babbage	2006 29er World Champ, 2nd Moth Worlds
Dalton	Bergan	2006 49er NA Champ	2005 49er NA Championship 2nd
Anthony	Boscolo	2008 29er US Champ	1996 US Double Handed Champion, Bemis Trophy
Sean	Couvreux	2001 Rolex Olympic Classes 49er 2nd
Rob	Gough	2009 Victorian State Champs, 2nd
Bora	Gulari	2008 NA Champion	2008 PCC Champion
Kevin	Hall	2005 Finn US Champion, Olympian
Hans	Henken	2008 29er Euros Bronze
Morgan	Larson	2007 49er NA Champion, 3x 3rd Worlds
Andrew	McDougall	2008 World Championships 2nd
Charlie	McKee	2001 49er World Champion, Bronze Olympics
Jonathan	McKee	2001 49er World Champion, Gold Olympics
Nigel	Oswald	2000 UK National Champion
Nathan	Outteridge	2008 49er World Champion, 2009 too
Simon	Payne	2006 World Champion, 5x Euro Champ
George	Peet	2005/2006 Volvo Ocean Race
Arnaud	Psarofaghis	2008 European Champion, 2009 too
Chris	Steele	2007 Optimist World Champion
Rohan	Veal	2005 World Champion, 2007 too
Tim	Wadlow	49er Olympian, 2nd 2007 49er NA's

Surely there are people with great sailing achievements I forgot or whom I have not met yet.

See everyone at the regatta.

Pimp your ride

The following sails are available:

• Production V6- Best for CST 351, 352 and 353 or Standard Bladerider mast. Used ONCE for 10 minutes- make offer.
  
• Production V8- Best for CST 352 or 353 or Southern Spar. Used 10 times, cloth in great shape, luff sleeve a little tattered, but I can fix- make offer.
  
• Production V10- Best for CST 354+ or Southern Phat Boy. Brand New
  
• Development Sail v7AP. Slightly deeper sail, suitable for larger sailor and best on softer mast- used twice, make offer.
  

Also available in time for the Worlds are:

• North Sails Narrow Mast Cams (Compatible with North, KA or Bladerider sails)
• North Padded Spectra Hiking Straps (For that "Locked in" feeling with your machine)
• North Carbon Batten Sets at 400g
• Carbon Shrouds- gucci!

Please inquire with me at: chris at design dot northsails dot com

Another Championship

TNZ sailor Kevin Hall winning the Oregon State Champs in the gorge- photo credit to Pacific Fog

Been too busy to blog over the last couple weeks with North Sails Design services finishing some Virtual Wind Tunnel and VPP studies for the 100' Alfa Romero, VPP/CFD development for a canting keel 80'er in build at McConaghy Boats and load annalyisis for a 90' Cat. Hopefully my lack of blogging does not get me kicked out of the Moth Class!

The US Fleet just finished a tune up regatta in the Gorge. The West Coast fleet has been getting pretty impressive where half the racers were former olympic sailing team memebers. Kevin Hall used his North Sail with Southern Mast in the 1st half of the regatta to devistating effect. Adam Lowry also used the V10 mainsail to great effect and posted a 5th (Did I mention Adam is 6'6" and 89kg).

Nice Video, also from Pacific Fog of the racing- check out Kevin motor by everyone off the line.

Southern Spars Kit

Big week this week, got my new Southern Spars mast and boom. These are some seriously nice pieces of equipment. The mast sets up perfectly with the V10 mainsail and should be good with the V8 too. The main difference between the Southern Rig and the CST rigs is a slightly smoother taper which makes for a stiffer tip. This allows for the mainsail to blade off very smoothly in the head rather than the traditional head dumping open which we have all become accustomed too.

Below are some pictures:

V10 Mainsail with moderate downhaul on Southern Rig and Boom

V10 mainsail with high downhaul and vang on Southern Mast and Boom

Oval boom is 25% stiffer making vang changes more effective

Vang cleanly ends internally for less windage

Normally I hate metal fittings on race boats, but the hounds attachment on the Southern Rig is very sexy, a well engineered stainless fitting for minimum windage, maximum reliablity and comparable weight to a carbon end

Spreader attachment fitting- very small, very strong, very light

Mast joint with recessed set screw

Sweet package!

If you would like more info on the Southern Spars, please feel free to drop me a note at:

chris at design dot northsails dot com .

Pricing for the rigging is as follows:

Mast 1550 NZD 871 USD 662 Euro 594 GBP
Boom 920 NZD 517 USD 393 Euro 352 GBP
EC6 shrouds 756 NZD 425 USD 323 Euro 290 GBP

(Headstay, Shrouds, Backstay) Shrouds and loops are 28g vs 120g for standard wire rigging. Carbon rigging is 2mm diameter vs about 3mm for wire.

If you are interested in a sail, please visit:

http://www.bladerider.com.au/

http://www.northsailsod.com/

Silver Bullet?

Moth front and center at North's Headquarters

Great start for the North Sail's International Moth program. Our V7 and V8 designs have been used in only three championships to date. In each of these three events only one sailor has used the North Sail for the entire event. However, in each of these events the lone sailor with a North Sail convincingly won the regatta:

2009 Australian Championships- 1st Place Nathan Outteridge (North Sails V7 MH)

2009 US Midwinter Championships- 1st Place Chris Williams (North Sails V7 MH)

2009 Victorian State Championships- 1st Place Rohan Veal (North Sails V8)

This past weekend at the Vic States Rohan raced with the new V8 design. Rob Gough from Tasmania also used a North V8 in the first two races, taking a 1st and a 2nd with the sail before heading back to Tasmania. Both Rohan and Rob were using new Bladerider VRX's which have been immaculately constructed. Rohan was using Bladerider spars and Rob was racing with a CST 353 mast.

These two new V8 sails were having a slight problem keeping the cams rotated, we are looking at a couple different details to solve this problem (Changing battens stiffness, stronger luff sleeve material and revised orientation, batten angles, etc). I am sure both Rob and Rohan would have been even faster with sails that had better cam rotation. Once the sails are 100% we will be starting our first production run of about 50 units.

The first batch of Southern Spars masts and booms have been shipped out. A few of these rigs will be tested in Hawaii as well as the first North Sails V10 design.

Winning equation for everyone to think about: Bladerider + North Sail = Silver Bullet

What's on YOUR mast?

Southern Spars

MemBrain Model of Southern Moth Rig

I always enjoy working with Sparmakers, it was one of my favorite parts of the AC design and luckily a very large part of North Sails Design Services work.

One of the things I find fascinating with mast analysis is that simulations can be checked with hand calculations pretty easily. This is something which is not possible with sail design, maybe this is one of the reasons that sail design still is very much a mix of art and science where mastmaking, while still a very creative process, is a pure engineering exercise.

Working with Southern Spars is always great, they have more engineers in-house than most of the other mastmakers combined (I don't think that is an exaggeration)! So there are always new tricks to learn. As everyone will soon know (Or should have figured out by reading the sail selection chart) the new Southern Rigs are a little stiffer than most other moth rigs.

Right now we are developing the V6 and V10 designs. North Sails Cape Town has built a lot of test sails so far for the Moth, so it was important to try to model the Southern Rig carefully to get the luff curve perfect in order to keep our prices affordable. Therefore a lot of homework was done to hopefully get the V6 and V10 designs perfect on the 1st couple prototypes.

The above graph is the measured deflection and predicted deflection of the CST 351 tubes. This test was required to calculate the EI's (Stiffness and Stiffness distribution) of the most common skinny mast.

Two Southern Spars tubes are being offered, the Standard P1 tube and the Phat Boy tube for sailors above 85kg or so. The theory is that larger sailors apply more force through greater Righting Moment and therefore force masts to bend more than a smaller sailor.

Therefore it is possible to design two different stiffness masts which will bend the same if a more powerful sailor is using the stiffer mast. This is critical for North Sails because by understanding this relationship we can make a mainsail design which should work for both rigs as long as sailors choose a rig which is appropriate for their size and fitness. This also gives larger sailors a more level playing field as they will not loose as much power through added mastbend than the average mothie.

The chart above shows the total mast deflection of a CST 351, Southern Spars P1 and Southern Spars Phat Boy rigs. Also shown is the Southern Phat boy rig with an additional 10% more downhaul which is a good measure of the added mastbend the stronger sailors can exert on the mast (Mostly through side bend) than the average mothie.

Side Bend of spars modeled in MemBrain

Fore/Aft predicted bends

Please feel free to contact me if you are interested in a Southern Spar for your Moth and I will put you in contact with your closest Southern dealer. Prices and info on the Southern Spars Element C6 micro carbon rigging to follow...

Moth Midwinters

Just back this week from the Moth Midwinters (20 hour drive down and 30 hour ride back home through a snow storm). We had a small fleet (Only 3 Boats) but had a great three days practice before the regatta where we all were able to try some new things. Most importantly for myself, I was able to try the V7MH design which is the same sail that Nathan won the Australian Nationals with. The sail setup great on my CST 352 rig, but I am looking forward to giving it a try on the Southern Spar as soon as it arrives.

In other news, the 1st batch of V8 sails left for AUS, although they just missed delivery for the Adelaide International Regatta. Hopefully we will have news to report on the new designs next week. We will then go straight into production of the V6 and V10 designs.

Also note that there are two V7 AP designs left for sale. Please drop me a note if you are interested. One sail is unused and the other only used three times. These would be good sails for larger or stronger sailors with a standard bladerider rig, Fastacraft Mast, C-Tech or a CST 351 mast.

Details will be announced for the Volvo Ocean Race Moth Expedition regatta in Boston next week. Posibility of a dozen boats making it the biggest event on the East Coast to date.

Enjoy the pictures from testing before the midwinters. As always, hospitality in New Orleans was once again amazing. Next years regatta will be Feb 17-20th.

Sail Model Guide

Overlay of the V6, V8 & V10 mainsail designs, note similar mold shape

In the latest Mothcast Bruce McLeod and Luka Damic raised the point that the new North Sails V-Series of models is a bit confusing (Thanks for pointing this out!). Obviously our intention was not to confuse the market, so I have tried to clarify things for potential customers. (By the way, if anyone ever has questions, please feel free to send me an email: chris at design dot northsails dot com.)

Concept- As stated before our concept and North Sail's philosophy is always to offer only the highest quality and fastest sails possible. After months of research and testing, we concluded that due to the range in rig stiffness and sailor sizes that a single sail design will never be able to compete against sails which are more optimized for a specific mast. Furthermore we we did not want to force our clients to buy a mast to match our sail design (Similar to what is done with windsurf sails).

Therefore we identified a range of luff curves for the various moth masts and then modified the sail designs to suite these masts. The V6 design therefore has 10mm more luff curve than the V8 and the V8 has 10mm more luff curve than the V10 design.

By tailoring a design to a specific range of mast stiffness we can then adjust the head width and sail shape. For example, a stiffer mast can support more girth in the top easier- which is easy to accomplish with the area saved by taking out a little luff curve.

See the image below to understand the effect of luff curve on the head width:

Similarly a sail design optimized for a softer mast needs to be slightly finer in the molded shape in the front to prevent the sail from being too draft forward in lighter conditions. This effect can be seen in the image below:

Further optimization- In a perfect world our lighter clients will sail with slightly softer masts than our heavier clients. Therefore lighter sailors would end up using the V6 design and heavier sailors using the V10 design. However, as one can see in the images, the sails are not radically different from each other. A rider who wants to have a more customized quiver of designs may end up with a V10 design for lighter conditions and a V8 sail or stronger winds. This would allow the V10 sail to setup with less downhaul in light winds for a given sail depth. We will continue testing these concepts as time goes by and can help our clients decide what is the best designs for their needs.

Over the next couple weeks we will be testing different mast/sail combos and we will give our suggested setup once we have more data.