Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 15-09-2009, 17:05   #16
Registered User

Join Date: Nov 2005
Location: Ohio
Posts: 2,311
For us creep would also be a problem. We use -40 rod and preset the caps to 30k. It is a very tall rig.

If we blow a runner well, that's a pain but the rig should stay up. If we blow a cap we are out $500k for a new spar.

Just curious Nick, why not rod?

Quote:
Originally Posted by s/v Jedi View Post
The UV damage is something I can live with. I have runners from that Samson Amsteel blue for four years now and I don't believe the degradation continues further into the core. Even the outside is still smooth like new, but bleached.

The problems I have with it are creep, working load and the missing data on shockloading. The problem with creep is that my capshrouds would grow more than 3 inches a year and I would need to tune monthly. Working load is only 20% of breaking load and above that 20% all bets on stretch and creep are off. I will already have 15% pre-tension! And the missing performance data of shockloading will prevent me from buying it. But, I don't need it yet as everything was replaced only 4 years ago. So I can wait and see how it works out with Dynex Dux and may be something else comes around.

ciao!
Nick.
__________________

__________________
Joli is offline   Reply With Quote
Old 15-09-2009, 21:45   #17
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
Quote:
Originally Posted by Joli View Post
Just curious Nick, why not rod?
Well, let's see. First, our rig was designed for 316 1x19 wire. It is continuous rigging without backstays, so intermediates terminate at the same chainplates as the capshrouds. For rod, this would mean those "spreader-bends" and they scare the hell out of me (fatigue!). So, imo spreader cups and discontinuous rigging are the way to go with rod which means a re-design of our rig.

Diameter. We could go from 12mm dyform to 11.2mm (-30) rod: not much difference. Weight: 0.513 vs 0.542 lb/ft : not much difference.

Durability: for a cruiser, I don't really like the close tolerances needed for the cold heads and the seats in the fittings.

What I do like is a stiff rig where you feel a gust not being absorbed by it, but immediately converted in acceleration of the boat. I noticed a significant improvement when we changed lowers and capshrouds to Dyform and know rod would be even better. I also know Dynex Dux would be a step back.

So, in the end, we are a cruiser and I am happy with what we have. I would love to save weight up there, not just a bit like changing to rod, but a big leap like with synthetic, yes. But for now, the synthetics seem either too expensive for us or they don't perform good enough.

Next time we replace the rigging, I will probably go for either Dyform or a synthetic. May be everything changes (I hear rumours about Dyform not being available anymore) and I select regular 1x19 or rod, who knows?! ;-)

cheers,
Nick.
__________________

__________________
s/v Jedi is offline   Reply With Quote
Old 15-09-2009, 22:15   #18
Registered User
 
Jmolan's Avatar

Join Date: Dec 2007
Location: Mexico/Alaska/Oregon
Boat: 34' Searunner Tri
Posts: 712
see if this will post

Seems I have to add a line in here to get this to post...OK so I add a line...:-)

Quote:
Originally Posted by s/v Jedi View Post
The UV damage is something I can live with. I have runners from that Samson Amsteel blue for four years now and I don't believe the degradation continues further into the core. Even the outside is still smooth like new, but bleached.
Quote:
Originally Posted by s/v Jedi View Post



What you are seeing is the dye coming out. SK-75 is white when it is untreated


The problems I have with it are creep, working load and the missing data on shockloading. The problem with creep is that my capshrouds would grow more than 3 inches a year and I would need to tune monthly.



If I may ask, where did you get those figures?


Working load is only 20% of breaking load and above that 20% all bets on stretch and creep are off. I will already have 15% pre-tension!



That is the figure you work from.....the 20% of breaking strength that creep will start at is over a long period of time. Not in normal sailing cycles. The other loads are dynamic and won't contribute to creep. Pretension is the only load that contributes to creep if it is high enough, over a long enough time period.

You can view this data and the difference of the 1x19 wire, rod, and Dux

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


If you up it one size to 15 mm you get Breaking strength of 61,400. At 15% you have 9,210Lbs. available before anything even close to creep comes in



And the missing performance data of shockloading will prevent me from buying it. But, I don't need it yet as everything was replaced only 4 years ago. So I can wait and see how it works out with Dynex Dux and may be something else comes around.
Stay tuned for more data as time goes on UV, stretch, fatigue and damping.......

For some reason this will not post.....




ciao!

Nick.
__________________
Jmolan is offline   Reply With Quote
Old 15-09-2009, 23:24   #19
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
JMolan,

Now that you mention it, the creep is much more than 3" per year actually. The 2nd graph on the link you provide shows the creep per year for a 50' section. A 13mm pre-tensioned at 7000 lbs gives 5" creep per year. But my capshrouds are longer, let's say 65' so I'll end up with 6.5" per year.

You seem to think that there is no creep under 15% pre-tension. But even when going low to 10% you get 1,5" of creep on a 50' length.

The 1st graph (stretch) is not the result of tests but are based on assumptions. It also assumes no constructional stretch. What we need is actual measurements, not calculations of theory.

Load: the safe working load is only 20% of breaking load. This means that the max load in your rigging while underway should not go over 20% of breaking load (max = SWL). I quote:

Quote:
We recommend sizing line for creep at static (constant) loads, using the creep chart provided. While making sure the maximum loads are not more than 20% of breaking strength.
So, my current 12mm Dyform has more SWL than 12mm Dynex Dux. Therefor, the 3rd graph comparing breaking strength is meaningless for rigging. It is the SWL that we need to know for sizing the rigging. For my cap shrouds, I need a SWL that's the equivalent of the SWL of 1/2" 1x19 in 316 stainless.
When you go over the SWL, the properties change. I quote again:
Quote:
For low loads (as a percentage of breaking strength) Dynex Dux has almost no constructional stretch.
I hope you understand my reservations. What is needed now is precise test results for stretch and creep and SWL that make sense for rigging. Plus tests for shock loading must be performed.

I believe DD is a wonderful line and indeed for fishing a perfect replacement for wire. But having a length paid out and winched in many times is a very different use than for rigging. "They" just don't know the specs because "they" didn't perform the tests for rigging application.

cheers,
Nick.
__________________
s/v Jedi is offline   Reply With Quote
Old 16-09-2009, 04:12   #20
Registered User

Join Date: Nov 2005
Location: Ohio
Posts: 2,311
Ah, the pin size, that would be the biggie.

We have continous rod with all terminating at the deck but the rod is fitted with spreader bends. Lewmar . I'm more comfortable with this then discontinous rod just because of the shear number of bits.

Cheers,

Joli

Quote:
Originally Posted by s/v Jedi View Post
Well, let's see. First, our rig was designed for 316 1x19 wire. It is continuous rigging without backstays, so intermediates terminate at the same chainplates as the capshrouds. For rod, this would mean those "spreader-bends" and they scare the hell out of me (fatigue!). So, imo spreader cups and discontinuous rigging are the way to go with rod which means a re-design of our rig.

Diameter. We could go from 12mm dyform to 11.2mm (-30) rod: not much difference. Weight: 0.513 vs 0.542 lb/ft : not much difference.

Durability: for a cruiser, I don't really like the close tolerances needed for the cold heads and the seats in the fittings.

What I do like is a stiff rig where you feel a gust not being absorbed by it, but immediately converted in acceleration of the boat. I noticed a significant improvement when we changed lowers and capshrouds to Dyform and know rod would be even better. I also know Dynex Dux would be a step back.

So, in the end, we are a cruiser and I am happy with what we have. I would love to save weight up there, not just a bit like changing to rod, but a big leap like with synthetic, yes. But for now, the synthetics seem either too expensive for us or they don't perform good enough.

Next time we replace the rigging, I will probably go for either Dyform or a synthetic. May be everything changes (I hear rumours about Dyform not being available anymore) and I select regular 1x19 or rod, who knows?! ;-)

cheers,
Nick.
__________________
Joli is offline   Reply With Quote
Old 16-09-2009, 07:36   #21
S&S
Registered User
 
S&S's Avatar

Join Date: Jul 2009
Boat: 48' 1963 S&S yawl
Posts: 851
Images: 6
Quote:
Originally Posted by Joli View Post
Ah, the pin size, that would be the biggie.

We have continous rod with all terminating at the deck but the rod is fitted with spreader bends. Lewmar . I'm more comfortable with this then discontinous rod just because of the shear number of bits.

Cheers,

Joli
Ours is discontinuous rod. I don't mind the bits because they're all longitudinally loaded. Lateral loads and flexing at the bend would give me more worries (only one spreader so it'd take a significant bend).

Joli- How often do you replace the rods or have them magnafluxed?
__________________
S&S is offline   Reply With Quote
Old 16-09-2009, 08:02   #22
Registered User

Join Date: Nov 2005
Location: Ohio
Posts: 2,311
We had the entire rig refurbished recently which included removing all the rod. The rod was sent to the spar maker who builds all the spars for Swan as well as many custom projects over 100 foot. They built our spar.

The rod was given a clean bill of health, no re-heading was required and it is back in service. We have a triple spreader rig so the bends are not severe.

Trust us, if the spar needs anything, it get's it. A gravity storm is not something we want.

Oh, here is the white paper from Navtec regarding rigging life.
http://www.navtec.net/support/rodrigging.cfm

Quote:
Originally Posted by S&S View Post
Joli- How often do you replace the rods or have them magnafluxed?
__________________
Joli is offline   Reply With Quote
Old 16-09-2009, 08:03   #23
Marine Service Provider

Join Date: Jan 2008
Posts: 30
Quote:
Originally Posted by s/v Jedi View Post
Jmolan,

I think you are absolutely right. When the time comes for replacing our rigging I will go this way if at all possible. Our capshrouds and lowers were 1/2" 1x19 but we replaced this with Dyform 12mm 4 years ago. The capshrouds are pre-tensioned to 20% of breaking strength on aft-swept spreaders; we have no back stays. Is there a Dynex Dux replacement for that? The rest is 10mm, 8mm and some 7mm.

About the tensioning: After using a halyard + winch, the Dynex should be pinched on the lower end to prevent it from slipping back while tying the knot. There's a special version vice-grip for that!

cheers,
Nick.
Nick, you need to size Dux for Stretch and Creep. You maintain a tremendous amount of pretension on your capshrouds. You would need 16 mm or even 17 mm dux to get you into manageable creep. 17 mm would give you less than 1/2 inch per year of creep-still high in my opinion. Dynex Dux Might not be the way to go for your boat.
__________________
jfranta is offline   Reply With Quote
Old 16-09-2009, 08:21   #24
Marine Service Provider

Join Date: Jan 2008
Posts: 30
Quote:
Originally Posted by s/v Jedi View Post
JMolan,

Now that you mention it, the creep is much more than 3" per year actually. The 2nd graph on the link you provide shows the creep per year for a 50' section. A 13mm pre-tensioned at 7000 lbs gives 5" creep per year. But my capshrouds are longer, let's say 65' so I'll end up with 6.5" per year.

You seem to think that there is no creep under 15% pre-tension. But even when going low to 10% you get 1,5" of creep on a 50' length.

The 1st graph (stretch) is not the result of tests but are based on assumptions. It also assumes no constructional stretch. What we need is actual measurements, not calculations of theory.

Load: the safe working load is only 20% of breaking load. This means that the max load in your rigging while underway should not go over 20% of breaking load (max = SWL). I quote:

So, my current 12mm Dyform has more SWL than 12mm Dynex Dux. Therefor, the 3rd graph comparing breaking strength is meaningless for rigging. It is the SWL that we need to know for sizing the rigging. For my cap shrouds, I need a SWL that's the equivalent of the SWL of 1/2" 1x19 in 316 stainless.
When you go over the SWL, the properties change. I quote again:
I hope you understand my reservations. What is needed now is precise test results for stretch and creep and SWL that make sense for rigging. Plus tests for shock loading must be performed.

I believe DD is a wonderful line and indeed for fishing a perfect replacement for wire. But having a length paid out and winched in many times is a very different use than for rigging. "They" just don't know the specs because "they" didn't perform the tests for rigging application.

cheers,
Nick.
Nick, Ultra High Molecular weight Polyethylene (Dynex Dux) is a different material than steel (rod or wire), it needs to be treated differently. You do not size Dynex Dux on Braking strength or SWL (based on breaking strength) like steel, you size it for its limiting parameters, Stretch and Creep. Since your boat has extremely high static loads, your limiting parameter will be Creep.
The data on our website has subsequently been substantiated with independent lab tests on the actual line, so believe it or not it is true and is a great product for standing rigging. Just keep watching as people around the world are grabbing onto this value leader synthetic rigging product. BTW, there will soon be an SK-78 heat stretched product from Hampidjan that could get the creep numbers down enough to work on your boat too.
I have alot more data on Dynex Dux than what is posted, trying to keep it simple. The best thing to do is get a rig quote from us and I can help you understand the material better.

Also, please see the newlsetter on sizing Dynex Dux for your boat for more information: http://www.colligomarine.com/docs/ne...ers/08-feb.pdf

John Franta, Colligo Marine.
__________________
jfranta is offline   Reply With Quote
Old 16-09-2009, 17:18   #25
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
John,

Let me start with saying again that I like the idea of synthetic rigging a lot, incl. going back to deadwoods. I am one of those who replaces shackles with spectra lashings, I have vectran halyards, spectra lifelines and so on and I do everything myself.

We replaced all the rigging in 2005 with Jonas from Trinidad Rigging and I was his apprentice during that time; swaging my fittings and putting on my Norseman fittings etc. Jonas told me what books to get about rig tuning and we tuned our rig together. I think I now know all there is to know about the rig on Jedi, which is more advanced than most cruisers.

We selected Samson Amsteel Blue 1/2" for our runners, which aren't really runners because they go all the way up to the masthead. They are used for trim (mast bending) and for high wind running as we don't have backstays on either mast. I love the new runners; all the problems we had before, like a retracted one wrapping around an upper spreader or slapping the spreaders cutting into the aluminium, are gone.

Now about Dynex Dux (I'll call it DD). What I write here is not to attack you; it is to explain why I think your website shows the wrong information. If you have better information, you should put that on your site instead of what's there now, not tell me to ask a quote to get the right information. I will ask a quote when I am interested in buying very soon, which I am not, so don't use your commercial skills on me, use your rigging knowledge.

Quote:
Since your boat has extremely high static loads, your limiting parameter will be Creep.
Why do you write that? (I assume you are a rigger because you post like you know everything about this) You know that this is the normal on every boat with a fractional rig or aft-swept spreaders, there is nothing extreme about it! The pre-tension should be 20% of breaking load. It can even be increased up to 25% if the forestay still sags at 20%. For masthead rigged boats, which is most of the cruising boats, it is a little less: 15%. I am well willing to exactly explain why this pre-tension is needed (absorb shock loading, reduce masthead movement to leeward by 50%) but you know all that.

So, my Bridon 12mm Dyform has a minimum breaking load of 31,746 lbs so my pre-tension is 6,350 lbs. Every boat with 12mm Dyform capshrouds has at least 15% = 4,762 lbs pre-tension.

We are a bigger boat than most, so let's look at something smaller: 3/8" capshrouds of regular 1x19 with a conventional masthead rig. The pre-tension should be 2,171 lbs. If it's a fractional rig, it will be 2,895 lbs.

Now we get to the question which DD we must select for that. We should select for stretch and creep you write, so let's do that. Stretch is similar according to your data so we have to look at creep. Now, what is reasonable? 1/2" per year? I can live with that.

So let's look at the graph for creep. to keep under 1/2" creep on a 50' section you get the following static loading:

7mm: 750 lbs (5% of breaking strength)
9mm: 1,500 lbs (6.25% of breaking strength)
11mm: 2,450 lbs (6.65% of breaking strength)
13mm: 3,500 lbs (7.14% of breaking strength)

So, for a masthead rigged cruiser with 50' long 3/8" capshrouds, 11mm DD is good and for a fractional rigged cruiser with 50' long 3/8" capshrouds you need 13mm DD.

If the masthead rigged cruiser has capshrouds 70' long it needs 13mm DD and if the fractional rigged cruiser has 70' capshrouds it needs more than 13mm but all data above 13mm is missing.

The masthead rigged cruiser increases shroud diameter by 15.49% and saves 75% weight (your site states DD weighs 1/6th the weight of wire so which wire is compared to which DD for that?! For rigging it is 1/4th in this case). The fractional rigged cruiser increases shroud diameter by 36.48% and the weight savings are unknown because the weight of DD is missing from the pages.

As the Colligo page is now, you need a boat with capshrouds of max. 3/8" (or may be 10mm) that are less than 70' long or there is no data for you.

So, who told me that creep is okay when staying under 20% of breaking load? Ah yes, JMolan: I hope you selected well under 10% for yourself or you will be tensioning weekly and re-splicing after a couple of years!

What do I want to see on the Colligo page: The following specs for DD:

- minimum breaking strength. That is 15% less than the current values I guess? (American specs are often 15% higher because they don't specify minimum breaking strength but some average or something which is utterly useless for rigging)
- SWL.
- stretch diagram up to SWL plus a 2nd one up to breaking load
- creep diagram up to SWL plus a 2nd one up to breaking load
- weight per 100' or whatever.

And this should be listed for sizes up to 16mm, or so that at least boats with 1/2" and 14mm shrouds can find the info they need without asking for a quote.

Ah, I almost forgot: about the stretch diagram. Read the small print, the graph is based on assumptions. You will need to put every size DD on a test bench, and measure the whole thing, not a single strand. That is the data you must publish. At the same time you can test the "set" or constructional stretch and publish that too.

cheers,
Nick.
__________________

__________________
s/v Jedi is offline   Reply With Quote
Reply

Tags
rigging

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Blackbird Carbon Fiber Guitar? markpj23 Fishing, Recreation & Fun 21 08-04-2009 16:24
Paint carbon fiber? mestrezat Deck hardware: Rigging, Sails & Hoisting 3 14-03-2009 21:49
Basalt fiber for yacht production fastcat435 Construction, Maintenance & Refit 14 26-02-2009 04:16
carbon fiber shrouds and forestay dpollitt General Sailing Forum 4 13-05-2008 15:59
Basalt Fiber for construction of yachts fastcat435 Multihull Sailboats 16 22-11-2007 23:35



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 19:27.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.