Replacement Running Backstays

[Captn_Black]

This - Amsteel Blue - in 5/16" is the best value/strength/wieght for my needs I could find, but happy to hear other suggestions.

[speedoo]

Originally Posted by Captain Jaz

I should add that my I'm planning some bluewater cruising, otherwise I'd more happily choose something less durable and avoid 30+knot winds...

I assume your rig is single spreader. So I am wondering why you think runners are needed? Did you add a stay for a cutter rig? If not, and you just want to beef up your rig, would a double backstay not be more economical and simpler?

[Captn_Black]

Funny you mentioned that, because I was just looking at that possiblity. The extra tackle involved might be prohibative though, I shall have to do some sums. The double backstay would also fit better with my plans for an awning and solar panel mount. Either way, something needs to be done anyway as the stays and shrouds are 9-10 years old now.

[speedoo]

Originally Posted by Captain Jaz

Funny you mentioned that, because I was just looking at that possiblity. The extra tackle involved might be prohibative though, I shall have to do some sums. The double backstay would also fit better with my plans for an awning and solar panel mount. Either way, something needs to be done anyway as the stays and shrouds are 9-10 years old now.

If you are concerned about your standing rigging due to age, runners are not the solution IMO. Why not have a trusted rigger look things over and replace what's necessary? And also advise you as to whether a double backstay is a good idea?

I think runners are needed on cruising boats only when you have a cutter rig, to keep the cutter forestay from bending the mast forward under load.

[timberboat]

I have just installed an inner forestay made of 9mm Dynex Dux. It is similar to amsteel and made in Iceland I think where it has replaced wire in fishing trawls. My running backstays are Amsteel. I would never go back to wire for any of these applications.

[speedoo]

Originally Posted by timberboat

I have just installed an inner forestay made of 9mm Dynex Dux. It is similar to amsteel and made in Iceland I think where it has replaced wire in fishing trawls. My running backstays are Amsteel. I would never go back to wire for any of these applications.

Why do you dislike wire for the inner forestay? If your staysail has hanks, isn't wire preferred because of what the hanks would do to rope?

[lint head]

There seems to be a lack of basic knowledge regarding continuous filament synthetic fibers and their application for standing / running rigging.

Tenacity is a measure of strength / weight ratio and is the breaking strength (grams-force) divided by the denier (weight in grams of 9,000 meters) and is expressed as grams per denier (GPD).

Steel varies widely, but typically has a tenacity of 3-5 grams per denier (cable or rod).

Kevlar, Technora and Twaron are poly-paraphenylene terephthalamide polymer (more commonly known as para-aramid or p-aramid) and typically have a tenacity of 20-22 grams per denier.

Vectran is an aromatic polyester liquid crystal copolymer made from 1,4-dihydroxybenzoic acid and 2,6-dihydroxynaphthoic acid and typically has a tenacity of 23-26 grams per denier.

Dyneema and Spectra are gel-spun ultra high molecular weight polyethylene and typically have a tenacity of 28-30 grams per denier.

Zylon PBO fiber is poly-paraphenylenebenzobisoxazole and typically has a tenacity of about 40 grams per denier.

The high stength / high modulus HS/HM) synthetic fibers have one major advantage compared to steel wire (or steel rod) rigging and that is strength / weight ratio (tenacity, GPD). One the other hand, all of the the HS/HM synthetic fibers share one or more of the following disadvantages:

Poor resistance to actinic degradation (aka, exposure to sunlight)

Poor abrasion resistance

Poor resistance to flex fatigue

Poor resistance to compression loading

Difficult or impossible to repair

Failure is difficult to predict

In the case of PBO, poor resistance to moisture

$$$$$

For "world class" racing sailboats where weight aloft is critical, a performance improvement of 10 feet per mile is HUGE, cost is pretty much irrelevant and short life is acceptable, synthetic rigging makes sense.

On the other hand, synthetic fiber rigging provides no tangible benefits on a cruising sailboat (other than bling / wow factor) and should be avoided for applications where failure could lead to major problems.

Just my opinion, YMMV.

[speedoo]

Originally Posted by lint head

There seems to be a lack of basic knowledge regarding continuous filament synthetic fibers and their application for standing / running rigging.

.......

For "world class" racing sailboats where weight aloft is critical, a performance improvement of 10 feet per mile is HUGE, cost is pretty much irrelevant and short life is acceptable, synthetic rigging makes sense.

On the other hand, synthetic fiber rigging provides no tangible benefits on a cruising sailboat (other than bling / wow factor) and should be avoided for applications where failure could lead to major problems.

Just my opinion, YMMV.

Very interesting and informative post. How do you define "synthetic fiber"? Anything other than dacron, or is it more complicated than that?

[timberboat]

Originally Posted by speedoo

Why do you dislike wire for the inner forestay? If your staysail has hanks, isn't wire preferred because of what the hanks would do to rope?

The inner forestay is detachable and stows by the mast. I didn't like the thought of 33 feet of wire banging around the rig. I am fitting soft hanks (spectra grommets) to the storm jib so chafe won't be a problem - although I spoke with two different rope manufacturers who admitted that piston hanks should be fine to use with Dynex. If you are worried you could always fit a braided cover to the line as sold by Yale etc.

Open 60s and 40s have been using this tech for years with no problems. I see no reason why it won't work on a cruising boat. On my boat, the inner forestay & runners are mainly used to stabilize the rig in heavy seas.

The Dynex Dux is about the same price as wire, is real easy to splice, and can be tensioned with a tackle.

[lint head]

Originally Posted by speedoo

Very interesting and informative post. How do you define "synthetic fiber"? Anything other than dacron, or is it more complicated than that?

speedo,

Sorry, I should have defined the term. Natural fibers include animal hair (e.g., wool), plant parts (e.g., cotton, flax, hemp, etc.) and even some minerals (e.g., asbestos, rock wool, etc.).

Synthetic fibers are typically polymers that are synthesized from petroleum based feed stocks. An exception would be rayon which is made by dissolving plant cellulose and reconstituting the cellulose polymer in a 'new and improved' form. Probably the best known synthetic fibers are 'nylon' (synthesized by the reaction of hexamethylenediamine and adipic acid to form nylon 6,6 polyamide) and 'polyester' (synthesized by the reaction of ethylene glycol and terephthalic acid to make polyethyleneterepthlate or PET). ‘Dacron’ is not a material, but rather an expired (?) DuPont trade name for PET fiber.

Hope that helps!

[speedoo]

Thanks lint head. But I am a bit confused. Surely you are not saying there is no place on cruising boats for ropes made of nylon (dock and anchor lines) and dacron/PET (running rigging)?

edit: Maybe what you meant to say in your first post was that synthetic fiber has no place in standing rigging on a cruising boat?

[speedoo]

Originally Posted by timberboat

The inner forestay is detachable and stows by the mast. I didn't like the thought of 33 feet of wire banging around the rig. I am fitting soft hanks (spectra grommets) to the storm jib so chafe won't be a problem - although I spoke with two different rope manufacturers who admitted that piston hanks should be fine to use with Dynex. If you are worried you could always fit a braided cover to the line as sold by Yale etc.

Open 60s and 40s have been using this tech for years with no problems. I see no reason why it won't work on a cruising boat. On my boat, the inner forestay & runners are mainly used to stabilize the rig in heavy seas.

The Dynex Dux is about the same price as wire, is real easy to splice, and can be tensioned with a tackle.

OK, I understand. My inner forestay is currently not detachable, but I am considering making it detachable. However if I do, I will plan to stay with a wire forestay and rig a fitting on the mast to secure the forestay. This is a solution that a lot of cutter sailors have used and I prefer it as it allows me to keep the hanks I already have on my staysail and storm jib.

[lint head]

speedo,

Correct, I was trying to say that, IMO, the high strength / high modulus synthetic fibers listed in my first post should not be used in cruising applications where failure is catastrophic. That would certainly include standing rigging and in some cases, running rigging.

Dyneema and Spectra are strong and float, so they make good towlines; IMO, keeping the mast up is a little more important.

FWIW, polyester and nylon are NOT high strength / high modulus fibers. Their tenacity values are only about 8 and 9, respectively.

To clarify, I have absolutely no problem with using the HS/HM stuff for racing sailboats. The risk / reward / cost ratios are 'rational' in that arena.

HS/HM fibers will probably become common for standing / running rigging on cruising boats in the future, but the technology is still awfully young. I make my living with this stuff (not in boating) and I don't think it is ready for everyday use in critical applications.

[speedoo]

Thanks for the clarification, lint head. It's great to have input here from people with some expertise, but no vested interest. I have so many issues to address with my boat before I go cruising, that I have zero interest in experimenting with new technology that has not yet been proven as safe and cost effective for cruisers. So I will stick with wire for my standing rigging for now, with the possible exception of the new runners that I will need within 6 months.

And as someone who used to race a lot, I can appreciate the importance of the new exotic ropes with very low stretch and light weight for sheets, halyards and control lines. (I still have some J-24 kevlar spinnaker sheets laying around somewhere.)

But now as a full time cruiser, stretch is not as much a concern... now it's safety, good performance, low cost and durability. Therefore dacron for all my halyards, sheets and control lines.

[Captn_Black]

Thanks for all the info guys, I'm still leaning towards Amsteel blue, and its good to here there are grommets to reduce chafe, and i've already seen some other columbia 27' s with 2 back stays, so i may do that, and possibly change the shrouds to give more support if they break, tho keep the forestay on 1/19 ss i think because of the furler. I can splice, and if i use the same guage line for shrouds and stays it will be easy to carry spare. And it would still work out the same or less than steel, probably less as I can do all the work myself.