ask an aussie

Started by David Chapman, March 19, 2012, 02:30:01 AM

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Justin Scott

Quote from: David Chapman on March 25, 2012, 08:21:34 PM

our North sails were bought in the UK, our sails have no blue strands/yarns in them
like the North american ones... I have no idea why and it makes no difference.

The blue strands are Cysteema (a Roche/Genetech product). The advantage of cysteema is that in addition to extremely low stretch characteristics it does not shrink at all, so it prevents the Mylar shrinking in prolific sunlight. The downside is that it is excruciatingly expensive.  
Viper - Mambo Kings
Right Coast Refreshments Committee

Craig Wilusz

Justin, this might very well be an issue of language.  Were the spreders cut, were the spreader tips adjusted, etc.  If spreaders were cut, that is the question, if spreader tips were adjusted, then no big deal.

C
Craig and Deborah
#100 Myasasaur

Dave Nickerson

Drew, who was on the boat, said that the spreader tips were simply adjusted using the builder supplied clevis pins at the spreader tips that are supplied with multiple holes for adjustment.  Nothing was cut other than some electrical tape.  Garth's details show the resultant spreader sweep at 330 mm.  Our class min in the rules is 280 mm.
Viper #208 - Noank, CT

Jay Harrell

Quote from: Dave Nickerson on March 26, 2012, 08:08:28 AM
Drew, who was on the boat, said that the spreader tips were simply adjusted using the builder supplied clevis pins at the spreader tips that are supplied with multiple holes for adjustment.  Nothing was cut other than some electrical tape.  Garth's details show the resultant spreader sweep at 330 mm.  Our class min in the rules is 280 mm.

Thanks Dave!  Sorry my original mis-read of the article.

I still would like to know more about the "new factory spreader angle".  How is it different from before?

Dave Nickerson

Researching North's spreader angle statements with Rondar.  Will reply when I have some facts.
Viper #208 - Noank, CT

Craig Wilusz

Thanks Dave.  All this with  American English, boy, imagine if the Brits, Aussies, and Islanders got into this.

C
Craig and Deborah
#100 Myasasaur

Justin Scott

Quote from: Craig Wilusz on March 26, 2012, 07:05:52 AM
Justin, this might very well be an issue of language.  Were the spreders cut, were the spreader tips adjusted, etc.  If spreaders were cut, that is the question, if spreader tips were adjusted, then no big deal.

C


Yup. the language in the article was "shortened" rather than "cut". A better choice of word would have been "adjusted", but before we rag on Garth too much, I think we should celebrate and appreciate detailed sharing of information like that.

Garth pulled out the cotter pin and went to minimum length from the max length.  As one of the "East Coast" guys who has been playing around with tune I dont agree 100% with how Garth sets up his boat but I applaud 110% the sharing of information by the top sailors .

Eg, Garth remarks on softer rig tension. Garth has a heritage of 5-0-5 and performance dinghy sailing. I have been going faster and faster in big breeze by really whaling on my uppers more than previously. I now have a bigger variance between my light, medium and big breeze on my uppers and less of a variance on my lowers than I used to have.....and it seems to be working. In big breeze my headstay stays taunt upwind and the mast in column downwind. If it gos light, I am quite aggresive about easing the uppers to develop sag in the headstay and power up the jib.

For all participants at Charleston Race Week I am preparing a laminated sheet which will include bullet points from all the top sailors of tune and go fast tips for the Viper.

If you want one then come to CRW.......or the NAs in Marblehead.
Viper - Mambo Kings
Right Coast Refreshments Committee

Paul Young

Just to clarify, for the paranoid amongst you, there is no new sweep position on the spreaders. Garth pulled the spreaders inwards, from two holes showing to no holes showing, and no spreaders were physically cut or harmed during this incident.

Just for the record, the precise sweep of the spreaders and their length is not that important on a Viper, what matters is the relationship between spreader sweep, length and rig tension. For example, if you shortened your spreaders (as Garth did), you will have less prebend for the same rig tension. You would acheive identical prebend by either keeping the same spreader length and rig tension, but sweeping them forwards a little, or by keeping the same length and sweep but reducing rig tension. There are three ways of getting the same setting, and which way to go is an owner choice.

What is pretty evident is that when you look at the results is despite the open sailmaker policy and the slight differences in boats over the years, is how close and open the racing is. In last years EFG series 19 boats were in the top three over the races, all of different vintages, with different makes of sails and crew weights, and in Miami the sane applied, with a two year old boat winning from a 13 year old boat in second with race wins by brand new boats and one year old boats. That is about as One Design as you can get!

Paul.

Drew Harper

#23
Garth is an engineer and a damn good one. We went through an 8 hour tuning session (if I have to pull that Loos Gauge ONE more time...lol).

Chris Snow, Garth and I went through an entire range of settings working throughout the anticipated performance curves.

We ended up with the mast slightly straighter (still with the minimum of 3.5" prebend) and firmly blocked (though a varying number of blocks). Garth wanted to change the spreader sweep to some dimensions that Ched had given him. Ched has spent the majority of his time on Justins boat which has carbon rig number one and, I believe, slightly different brackets. I vetoed that saying that we (Rondar) need North to not change the rig from stock angles/drilling as it will then void the warranty. All it took to get the rig where we wanted it was to move the spreader tips in to base (no holes showing). We softened up the rig during the light, built in some mid-mast sag and added in some headstay sag to power the boat up.  The boat was very fast with our final tune setup in 8 TWS. We then had a chance to bone the rig in preparation for sailing in puffs to 30. We managed to get the boat depowered quite nicely and it was just a matter of some jib lead changes for wave conditions to allow for some groove nuances. Justin mentions 'whaling on the uppers' and we truly did that. We were damn near two blocked and I spotted the rig with the kite up in huge puffs and she was nicely prebent and completely in column. This allowed us to just concentrate on going fast without worrying one bit about the rig. Kinda huge in big breeze.  All of the various tune setups will be published in the new Rondar/North Viper640 tuning guide which is underway. Additionally we are photo-documenting the sails with specific tune setups so that everyone has a visual reference of the intended 'shape.'

I'm very grateful to Garth and Chris for all their help. Good guys and hella fun to sail with.

http://www.onedesign.com/One%20Design%20NA/tabid/23032/Default.aspx?news_id=3156


Quote from: Jeff Jones on March 25, 2012, 01:26:54 PM
http://www.onedesign.com/One%20Design%20NA/tabid/23032/Default.aspx?news_id=3156

Great report from the west coast north guys who sailed the Rondar factory boat at last weeks San Diego nood.

Some really great tips in here about trimming spreaders down to make up for the wide variance mast geometry.


The only variance in mast geometry that I am aware of is between tin and carbon rigs. I have rigged 30+ masts since I started selling Vipers. I have seen very little difference in rigs. We did have some spreaders come undrilled which was just a production issue. We also doubled the thickness on the spreader bracket two years ago but there was no change in geometry. We also had 5 masts that the caps were installed in the wrong position (2.5") high. Rondar replaced all of those and they are now imbedded as 'emergency' masts throughout the West and Texas. (we ended up with them all).
#189 UK Built Mark IV Viper "DILLIGAF"

Jeff Jones

I could have used a better choice of words in that post.  I throught the write-up by Garth was really great.  I wish i would have spent some time picking his brain when we were in San Diego.

I find that i cant rake my spreaders back on my older masts (both 31 and 58's) as far as all of the new masts i've measured.   Might be able to drill another hole but thats an uncomforable option and it would be very close to the front of the spreader edge.  I wonder if that is consistant with all the pre-2009 spars?  Justin, what is your furthest aft setting?

Mine measured 11.25" (285 MM) from the back of the track.   We seem to go pretty well but carry a lot more cap tension to bend the mast.  To get into the 4" range we really have to crank them on.  That would seem to benifit a flat mainsail or very heavy crew?

The North tuning guide gives a spreader depth of 29cm (5mm more than mine) which was where Garth appeared to be heading.  








Matt Sole

Ched did a measuring session in Miami when we had out tuning weekend. We were using the measurement from the back of the mast to the string tied between the spreaders. We found massive difference in the 5 or 6 rigs we checked.

My spreaders were at 271, so I have to set the tips max out and I am still 4mm short of class legal. 155 was way over at around 320mm. 178 was around 310mm I believe.

Considering the fittings look to be all drilled out in the same locations, I can only assume the holes on the spreaders are not drilled very accurately.
Booze it or lose it

Hijack GBR 78

Drew Harper

The spreaders are all drilled on a jig so therefore pretty damn close to consistent (for handmade/drilled goods). I have received two boxes of boats wherein spreaders were not drilled and we tried to stay very close to the stock spreader drilling.

Here's a shot of the spreader brackets. Pretty consistent. I do think the math is problematic. Just a little bit off, say 1mm, adds up to a bunch of degrees. I suck at math so there's folks here that can make sense of this.
#189 UK Built Mark IV Viper "DILLIGAF"

Matt Sole

more like 1 degree adds up to a bunch of millimeters.
Booze it or lose it

Hijack GBR 78

Justin Scott

Jeff,

I will measure my sweep again at CRW. Perhaps dave N could take a sample.
I agree with you that we will make our sailmakers lives and our own lives a lot easier if we all sailed with a consistent spreader sweep. 

My mast spreaders (one of the very first carbon masts) came with 3 adjustments for spreader angle and 3 adjustments for spreader length. I sail with angle in the aftmost position and spreader length in the mid position.

My recollection is that with the angle in the aftmost position, all three speader lengths comply with the class required sweep measurement. In the forward position I had to have the spreader at max length to comply with class rules.

You can achieve the same sweep (measuring from a line between the two ends of the spreaders to the back of the mast) in two ways. (1) Spreader angle forward and spreader length max long or (2) Spreader angle aft and spreader length shorter.

I love to experiment so I tried both. The amount of rig tension to get the same amount of prebend  was not noticeably different so I set up based on the same rig tensions for a couple of weeks in each configuration. Then I went sailing. To my very untutored and amateur eye:
Option 1 - The rig seemed slighty stiffer, side to side, laterally.
Option 2 - The rig seemed slightly stiffer, fore and aft. My headstay seemed a touch tighter in similar wind conditions.

So I went with option #2. There is so much that was not scientific about my experiment (wind, waves etc will vary), and any difference was pretty small, but hey we feel good about it. Just feeling good makes us faster!

I'm sure JB could model this on a computer.
Viper - Mambo Kings
Right Coast Refreshments Committee

Jeff Jones

Having consistant mast geometry through the fleet would certainly benifit sailmakers but more-so the 90% of us who dont have the skill-set or know how to mess with the rig and make things work given the cut of their sails we're using.  (without drilling new holes in their spreaders to match someone else's settings)

This would seem as simple as drilling the spreaders when they are on the mast, jig in place so they ensure that the spreader tips are in the same place relative to the mast tube.    I agree with Drew (assuming i understand him correctly) in that being just a fraction off on the drilling could make a big difference in sweep.   

Next time you speak to Ben P or Zimm, ask them to put "check spreader geometry" on their QC list before the boat get's delivered.  After spending some time with them down in New Orleans my confidence is high.   So to that question...  when guys?   (or is that for another thread wait, let's ask an aussie).         



Quote from: Justin Scott on March 28, 2012, 11:41:19 AM
Jeff,

I will measure my sweep again at CRW. Perhaps dave N could take a sample.
I agree with you that we will make our sailmakers lives and our own lives a lot easier if we all sailed with a consistent spreader sweep. 

My mast spreaders (one of the very first carbon masts) came with 3 adjustments for spreader angle and 3 adjustments for spreader length. I sail with angle in the aftmost position and spreader length in the mid position.

My recollection is that with the angle in the aftmost position, all three speader lengths comply with the class required sweep measurement. In the forward position I had to have the spreader at max length to comply with class rules.

You can achieve the same sweep (measuring from a line between the two ends of the spreaders to the back of the mast) in two ways. (1) Spreader angle forward and spreader length max long or (2) Spreader angle aft and spreader length shorter.

I love to experiment so I tried both. The amount of rig tension to get the same amount of prebend  was not noticeably different so I set up based on the same rig tensions for a couple of weeks in each configuration. Then I went sailing. To my very untutored and amateur eye:
Option 1 - The rig seemed slighty stiffer, side to side, laterally.
Option 2 - The rig seemed slightly stiffer, fore and aft. My headstay seemed a touch tighter in similar wind conditions.

So I went with option #2. There is so much that was not scientific about my experiment (wind, waves etc will vary), and any difference was pretty small, but hey we feel good about it. Just feeling good makes us faster!

I'm sure JB could model this on a computer.