HM rigging

[Gary]

Ok...I've got the bug. My first question. Is Dynex Dux and Amsteel blue the same thing? Seems the Amsteel is quit a bit less expensive. Going to be re-rigging a Bristol Channel Cutter.

oh cool...I'll be the first on my block!

Gary

[benz]

Hi Gary,

Amsteel blue (or any color) is not the same as Dynex Dux. Amsteel is given to 'Molecular creep' which just means it will get longer as time goes by if it is under tension, as it will be in shrouds and stays. So you would be forever tuning your rig, and occasionally re-splicing the Amsteel. Not practical.
But there is no shortage of threads in this forum (look in the archives), discussing various HM lines suitable for rigging.
Incidentally, I'm building a CG 31, very similar to a BCC, and will be rigging it with Vectran.
Good luck,
Ben

[Gary]

Thanks Ben,
I was under the impression that the Amsteel "blue" was a newer heat treated version of the original Amsteel. (not actually refer to the color)

Why did you choose the Vectran?

Saw my first CG31 just last week. Sailed in here to St. Thomas. What a great looking boat. It was owner built with the cabin stopping at the mast. Man you will love her when your done! Good luck.
Gary

[Bob Pingel]

I believe that Amsteel Blue (the material, which I think only comes in blue) in SK75 (the actual fiber) and Amsteel is SK60.

Dux is SK75 that is prestretched and heat treated to reduce creep and elasticity.

I have heard rumor that Marlow is creating a heat treated Spectra/Dyneema.

Bob Pingel

[Gary]

Here is the reason for my question.
Defender carries the Amsteel Blue (they have a silver/gray custom color they carry). "AmSteel-Blue is an upgrade design from Original AmSteel and it offers superior strength in the smaller sizes" and yes it is made out of Dyneema® SK-75 fiber. On Samsons site they rate the elastic elongation at 0.7% at 20% load.
Over at Colligo they are asking $4.84/ft for the 9mm Dynex Dux. While at Defender they are asking $1.99/ft for the 5/16 (closer to 8mm) Thats a HUGE savings!

My rig is 5/16 316 with wire splicing (Lyle's specs call for 9/32 and 1/4). This will take out over 65lbs aloft....how sweet it is!

Gary (and my trusty calculator)

[Jack]

Originally Posted by Gary

Here is the reason for my question.
Defender carries the Amsteel Blue (they have a silver/gray custom color they carry). "AmSteel-Blue is an upgrade design from Original AmSteel and it offers superior strength in the smaller sizes" and yes it is made out of Dyneema® SK-75 fiber. On Samsons site they rate the elastic elongation at 0.7% at 20% load.
Over at Colligo they are asking $4.84/ft for the 9mm Dynex Dux. While at Defender they are asking $1.99/ft for the 5/16 (closer to 8mm) Thats a HUGE savings!

My rig is 5/16 316 with wire splicing (Lyle's specs call for 9/32 and 1/4). This will take out over 65lbs aloft....how sweet it is!

Gary (and my trusty calculator)

Gary, what Amsteel is referring to is they upgraded from SK-60 Dyneema to SK-75 Dyneema. It also sold as Spectra and a few other brand names. It is all SK-60 or SK-75. I know the Blue is SK-75 and the SK-60 is Grey from Samson.

One way to compare is to take the strength charts and compare. Off the top of my head I think 7mm SK-75 is 10k breaking strength. Looking at Samsons chart I see they are using #8600 breaking strength on 1/4". If you move up to 5/16" you get 13,700 breaking strength. The 7mm Dux is #15,000 Breaking strength. Does not look like the same stuff.
I have seen some heated and stretched stuff from Marlow. It looks like the angle of the fibers are stretched out longer than the Dux. I am not an engineer but I believe if you lengthen the fibers to be more parallel you get more strength.

5/16" is very close to the 9mm Dux that will get you #26,500 breaking strengths. You can see it is not the same stuff. But Colligo will tell you you do not size for strength as much as you size for creep. Keep the static loads down to 10 or 20% of the working load and your creep is less than SS wire. As long as you are in the design phase drop John a note, he is very attentive to his customers.

Good luck with your project, sounds cool. I love BCC's.....:-)

http://www.samsonrope.com/index.cfm?...ope=192&inst=1

[Gary]

Thanks Jack, good point.
I was wondering about the "blue" as I saw no reference to the heat treating. I'm going to call Samson and Colligo and talk to them both. Then I need to actually calculate my static load and go from there. I'm wondering if there are any deferences in their testing and parameters for the figures they give. But If Samson is not doing the heat treating, then that would explain the difference in the ratings.

I like these kinds of problems and design puzzles....this is going to be fun! And in the end may boat will be so fast it will pass wind

Gary

[Jack]

I was curious and looked up the Vectran sheet.

http://www.neropes.com/product.aspx?...6C&lid=1&pid=5

And compared it to the Dynex Dux sheet

http://www.hampidjan.is/media/pdf/00...taflaagu02.pdf

One comparison I got (apples to apples) was for 11mm rope size. The other sizes are

1mm diferent.

So....11mm shows

Vectran......#21,000

Dynex Dux....#37,000

There are many other comparisons, and other factors. But the way to think of synthetic rigging is not just how strong do I need to hold the rig up, but how strong do I need to stop creep? By keeping the static load below 20% of breaking strength you will end up with next to no creep. The charts for this are at:

http://www.colligomarine.com/Colligo.../Dynex-Dux.htm

You can see the potential to have less creep than SS wire!

I used mostly 7mm for my 34' Searunner Trimaran. Cutter rig double spreader. The original specs were for 7/32" and 1/4" wires. We can really put a load on the rig with the stability we carry.

So far so GREAT!

As a little aside, I was talking to Hampidjan guys a while back about all this, he told me they are more interested in big boat stuff. They were producing 3" Dynex Dux with a double overbraid for an oil rig!.....It is "off the charts" I see 2" or 51mm has a breaking strength of 242 TONS!

Kee-rumba!....:-)

[Gary]

Great Jack, I'm getting the creep thing. Saw the chart from Colligo. The specs for my rig are 1/4 and 9/32. So I figured going 7 and 9mm. Using initial settings for wire my percentage will be around 3-4%. So that should solve the creep.

As far as the claim that it is cheaper than wire or at least comparable, I don't particularly agree. Yes, the line is slightly less expensive, but if you up size for creep it is actually more expensive. I did an initial estimate with 7 and 9mm Dynex with the ends and deadeyes. It would cost about $3200 to re-rig my 28' cutter. That will not deter me though. The thought of shedding about 70 lbs aloft is just to good!

Gary

[Gary]

As of now, notice how I qualify this, This is my plan.

I will use the Dynex Dux for my standing rigging. 7mm on the shrouds, whiskers and lowers. 9mm on head, fore, boomkin and back stays. I will stay with wire in Bobstay because of anchor line/chain chafe.

I will be using terminators and deadeyes from Precourt (in black). The medium series. Download there catalog here.
[www.precourt.ca]

Then I will use this black line for the lashings (New England V-100). That way the whole setup will be black. Hey, if you can't sail good you should at least look good! It's vectran with a braided sheath. This way it should hold the lashings well and not slip. Dynex is very slipery!
[www.westmarine.com]

Then to finish off I will rig a bowsprit traveler from Classic Marine.
[www.classicmarine.co.uk]

Then I will have may sails fitted with luff ropes made of Dynex. Rig a 2 part halyard led to a winch to host the sails with a Facnor Code 0 furler. This will be attached to the traveler.
[www.facnor.com]

So far I am estimating with furler, the cost of around 4000.

Gary
http://garyfelton.com