Staying with Synthetics

[osirissail]

- - There is nothing on a cruising boat that is "static." Rigging includes the mast, all its fittings, shrouds, stays, chainplates, hull - everything - twists and bends constantly. Fact of life on the oceans. In certain applications on a sailing ship you want lines to stretch a little or a lot to reduce impact loads on parts that cannot sustain such repeated pounding when you are offshore in heavy seas. Cleats and winches have been ripped off decks by snapping lines that do not have the ability to stretch. Even Stainless wire and rod rigging has stretch and flex engineered into it otherwise it would crack and break.
- - If you have lived onboard for a decade you will find salt crystals everywhere on board including interior spaces. Don't forget capillary migration and osmotic blisters caused by salt water entering the "solid" FRG hull.
- - UV is not a big problem in the high latitudes but down here in the Tropical and Equatorial latitudes, it dries and breaks down the best of things. UV chemical protection is based on "absorbing" UV radiation by the chemical. Once the chemical protectant has absorbed its limit it offers no further protection. Re-applying chemical UV protectants to standing rigging is not a viable option for cruisers. Heck, we don't apply it often enough on our canvas items - for two reasons: inconvenient and the stuff is horribly expensive.
- - So the northern latitude markets are a fertile ground for this type of rigging and most certainly racing boats. But until I see it on - round the world big racing yachts and surviving the ordeals they encounter and for quite a few years, then it is still in the "new" maybe it will work, maybe it won't work category. Long time and distance cruisers cannot afford a failure in mid-ocean so we tend to go with the old, tried and proven stuff. But again Stainless rigging was considered risky back in the days where galvanized iron rigging and tarred hemp and wooden blocks were the standard.

[Jmolan]

Have you contacted John at Colligomarine? I say this because he is the engineer/designer and know a whole lot more than I do about what you can and cannot do with the materials. I like to think there are all kinds of new/old solutions by using marlinespike methods. Please let us know what you find out.

Also, in regard to continuous line furlers:

I am considering purchasing one of Colligos units and sewing Dyneema line into the luff of my headsails. I currently have a large teak platform and full double rail pulpit on my bowsprit, but am thinking about removing those to move the weight aft. Instead of going out to the end of the sprit to change sails, I could add a pad eye to the end of the bowsprit and attach a block to that, through which I could reeve an outhaul line. To this line I could attach the bottom of the roller furler so that, when I want to change sails or pull one down, I could simply move the roller furler back to the deck. Then once I've attached the sail I want, I could pull it out to the end of the sprit and hoist the head, tightening up the sails low-stretch luff so that it freeflies a foot or so behind the jibstay.

Instead of welding a pad-eye. Consider lashing up a fixed point. Lashings are replacing all kinds of formerly hard spots now that lines are so strong. So you have a lashing and a "softie" as opposed to a pad-eye and a hard shackle. There is nothing new about this. Looks at any long distance race boat nowa day's. Fiber is replacing any hard points that they can.

Gary Felton has done a very similar thing on his BCC, though he used a hoop around his bowsprit rather than block and tackle to a pad eye:

What you are describing in common and very workable.



The Adventures of the Bristol Channel Cutter Shanti


My bowsprit is square and I'd rather not reshape it for a ring, nor do I understand why a ring is necessary. All that seems necessary is keeping the drum in place on the bowsprit?

Thank you all for your thoughts!
Aaron[/QUOTE]

[Jmolan]

some good reading by a well respected rigger/author Brion Toss

Brion Toss Yacht Riggers Fairleads Newsletter

Interesting he wrote this piece in 2004.

Shown here rigging a 48' wooden Mono-hull in Port Townsend with Dynex Dux, that is heading out to the Pacific.

[engineer-jason]

Great thread. Thanks everyone for the lively discussion.

Let me introduce myself by introducing my boat :-) She is a 40 foot sloop rigged custom steel sailboat with very roughly 10,000 pounds in the keel centered 5 feet below the waterline and mast rising to just under 50 feet above waterline.

I’m thinking through how I’ll replace the standing rigging (25 years old with some visible corrosion coming through) with HM fiber synthetics and have some very practical questions and ideas.

First, I apologize in advance for the rough terminology here. I don’t have all the terms down. Before you flame me for my questioning ways, take pity on a fellow boater just trying to make sense of the weather as it comes.

Basic rigging question: My boat has 2 spreaders. All the wires on the sides of the mast are the same diameter except the one that goes outside both spreaders and all the way to the top of the mast. It is larger than the rest. I can’t figure out why. Thinking back to freshman physics with vectors and forces it seems that in the more extreme cases the lines below this top line will have at least as high a load. That is if the boat is knocked down and the keel is exerting its maximum righting moment and the mast strains to pull the sails out of the water with the waves hopefully helping to bounce the boat back upright the leeward stays will be near slack and the windward stays will be stretched under a very high load. It seems unrealistic to believe there won’t be some stretch in the rigging in the extreme load case even with wire rigging and I’d think you’d want to keep the mast as straight as possible even if it deviates somewhat from perpendicular to the deck. Why would anyone use a larger diameter wire for the stay going outside both spreaders to the top of the mast? Unless I can find a compelling reason to do this with the new rigging I’ll simply use the same size rope for all these lines so they stretch proportionally together maintaining a straight mast. Unless I’m misreading the specs from New England Rope, HM ropes stretches something like 7 times more than wire so ensuring it all stretches proportionally together seems more important with HM fiber. If anything I’d be inclined to use larger rope for the lowest lines for two reasons: 1) mass lower in the rigging has a smaller moment than mass higher in the rigging and 2) I always reef the main when the weather is up and keeping the middle of the mast from sliding out from under the top seems like the challenge here. Thoughts?
Where is the cotter pin? I am scared that the deadeyes from Precourt can be undone any number of ways by potentially well meaning inexperienced crew/passengers who might also be drunk for example. I never worry that a drunk is going to sit down with needle nose pliers and perform the detailed and tricky task of working the cotter pins out of my turnbuckles and then get a sizable wrench to put 30 or 40 turns on the thing to release a wire stay. It is just too difficult a job requiring tools, skill, force, and determination. However, when I look at the Precourt deadeye by comparison it seems to almost invite the curious hand to innocently slacken the line and release the stay. When I set the turnbuckle I put in the cotter pin to ensure it stays put under any conditions. What provides this assurance with deadeyes? Here is the best answer I can think of myself: First, use the largest possible, massively oversized 8mm V-12 vectran looping back and forth between the deadeyes. Second, once all the pre-tensioning is done and the creep has been adjusted for, secure the 8mm V-12 at the point where it leaves the deadeye for the last time with two things: first, put something inside the 12 strand rope to increase the width so it cinches tightly in the hole in the deadeye and cannot pull though... one could even use a properly sized cotter pin :-) and second, just past the embedded cotter pin just thread an aluminum button sleeve like one might use on 8mm wire and crimp it down. To slacken the line one would have to cut off the crimp. I know you are going to flame me for the crimp idea, but please include a better idea with the flame. There would probably be some trial and error to figure out how to put such a crimp on V-12 effectively without damaging it too much but I wouldn’t have to worry about the mast falling down. Comments?
Why put the deadeyes down at deck level where there are uncountable hazards. They seem bigger than turnbuckles and on my deck would impede walking and invite lots of knocks from passers by. Precourt identifies the connection between the deadeye and the deck fitting as the weak link in their parts and the aluminum in such proximity to steel in the presence of salt water is problematic to say the least. Use something like cast stainless thimbles at both ends and put the deadeyes up off the deck at perhaps arm level or waste level or something. Why doesn’t everyone do this?
So instead of turnbuckles I’ll now have cast stainless thimbles and something. Quick Links seem to have larger working loads than shackles of similar size. Would an inspector object to 1/2 inch 316 stainless quicklinks connecting the cast thimble to the deck fitting? Is there a better alternative?
Stretch. Ok, ok, HM braided ropes are low stretch for ropes, but when I look at the numbers from New England Rope and do some calculations it seems they have about 7 times the stretch of the wire they will be replacing. For example an additional load of 10% of breaking strength of rope that is 50 feet long will stretch it roughly 4 inches. So I’m left imagining a circle of 8 inches diameter (actually an oval) that the head of the mast will move around inside. Doesn’t that seem like a problem? Seems like you definitely need all the lines stretching together to keep the mast straight.
Insurance, insurance, insurance. If I do this upgrade will they drop me or raise my rates or simply refuse to pay out for a demasting if they find I have HM aloft?
I’m not sure y’all can help with this one, but when I look closely at the attachment points of the wires for the standing rigging on my boat I have a hard time imagining how I’ll get the bulkier thimbles and deadeyes to “fit”. I’m not seeing how I can do a drop in replacement of wire with rope. I’ll probably have to replace/modify/relocate the attachment points/hardware of my boat. This could be the one thing to prevent me from moving forward with this project.


[osirissail]

Before you do anything buy a copy of Brion Toss's Riggers Handbook and study it. If you really want an authoritative answer to using HM on standing rigging - go to Brion Toss's website forum and ask him point blank.
- - Otherwise, those stretch numbers you gave would certainly rule out the use of HM on any standing rigging, IMHO. Especially if the boat was not originally designed for HM standing rigging.
- - I seriously doubt you could ever get a surveyor to sign off on a conversion from stainless wire to HM line. That would instantly negate any chance of getting insurance on the boat. There is a world of difference between a boat designed for HM rigging and a boat designed for stainless rigging or even boat designed for galvanized iron rigging. Given the real world problem of solar UV and salt water absorbing you would end up redoing the rigging every 2-3 years which might get a bit expensive.
- - If you want better life and strength replace your 1-19 wire with DyForm wire of the same size. That will significantly increase your rig's lifespan and strength providing the parts of the standing rigging are up to spec's.

[Jmolan]

Jason, welcome aboard. I see that you are new here. It is a fun place.

My advice would be visit Colligo and look over all the data there. The ropes you refer to are not what Colligo is using.

Home

Or go to the site and the email and phone number are there. John Franta is also an engineer, and he can help you sort through many of you questions.

There are a number of other threads here that have discussed fiber rigging. See what I can find.

http://www.cruisersforum.com/forums/...ons-21574.html

http://www.cruisersforum.com/forums/...ner-30407.html

http://www.cruisersforum.com/forums/...ing-10078.html

http://www.cruisersforum.com/forums/...ing-18184.html

[jfranta]

The only braided synthetic line with low enough stretch to use for standing rigging is Heat Stretched Dyneema, virtually no costructional stretch. Ours is Colligo Dux. See the stretch numbers here Dynex Dux | Colligo Synthetic Systems | Colligo Marine

Size it for stretch and creep, based on the creep tables on our website, and you will have no issues. turnbuckles or lashings can be used.

Boats have been rigged to 70 feet with this. One, steel ketch is on its way to Antartica.

Several boats in the heat of Western Mexico.

Call or email me with details on your boat if interested and I will get you a quote.

Stayed tuned to the website or on our Facebook site for more on the boats that are being rigged with this.

We will have a boat in the Miami Strictly Sail show with our rigging on it.

John Franta, Colligo Marine

[Jmolan]

This was part of Brion Toss's Christmas greetings by email.




Thoughts While Rigging
Brion will present a new series of Fair Leads columns to appear soon on our home page.

The first article in the new series is "Protocols for splicing Dynex Dux".

Sounds a bit rigger nerdy, but this stuff is of great interest to everyone in the sailing world who wants the most high-tech, sexy, light, durable, cost-effective standing rigging yet invented.

And, if you aren't ready to make the leap into an all Dynex rig, feature that you can carry a 200', feather-light, ropey hank of the stuff in your fo'c's'le for spare standing rigging. Handy to have out in the South Pacific or up the Inside Passage. You could loan it to a sailor in need and really be a hero!.....

Don't miss this new series coming soon!

[Geoff S.]

Hi, Jack;

Just this last weekend at the Miami show, I had a long chat with Frank, and I'm very interested in/darn close to convinced to going the synth route on the forthcoming complete re-rig on Diva. As anyone who has been bored to tears by my refit story, her return to seaworthiness has been a long process (coming up on 8 years, sigh), and we're probably talking another goodly year-plus. Frank hinted at a possible quantum leap, perhaps in the next year, to SK-90. It would be just my dumb luck to go whole-hog with SK-75 and have the 90 come out immediately afterwards! Any gut about how imminent its introduction will be?

Also, Frank mentioned that some tradeoffs with the sacrificial UV cover is that it makes splicing tougher, and also that you need to do a shrink-wrap on the ends to protect the cover's bitter ends. It does sound like the over-spec of the non-covered Dux vs. wire means that the opacity that occurs as the outer fibers degrade may give you that protection anyway and still be way-safe re breaking strength. Thoughts?

Thanks for the great treatise. I'm even more geeked synthetic rigging now!

Thanks,
Geoff Safron

[Jmolan]

Geoff, I am in Alaska right now, and only get to the computer once a week or so. I am glad you got to see the Dynex Dux in Miami. I know the guy with the Yawl is really happy with his new rigging.
I would not hesitate to go with SK-75 myself. If you have a year to wait, you could use the info that is available then. The only difference (I am guessing here) is you may, MAY, be able to go 1mm or so smaller with the SK-90. But I do not think we really know yet.
It's a bunch of fun, I am glad you are onboard.