my dream rigging

Hi all,
I started the thread about roller furlers looking for a solution for the bowsprit and jib. During that process I came upon a new kind of rigging. it’s synthetic line. Some form of this has been around for awhile, but very expensive. That has all changed now. In fact Brion Toss has rigged his personal boat with the stuff.

Two manufacturers have caught my eye. Dynex Dux and Amsteel Blue (it does come in blue but also other colors). I will probably go with the Amsteel blue as Defender has the line (in silver/gray) for half the price of the Dynex ($2.00/ft for 5/16). This is also cheaper than wire.

I will include some links, but here is a recap of the advantages/disadvantages:

  1. Can replace size for size (my wire is 5/16 and the Amsteel has a min breaking strength of 15000lbs)

  2. Most people are using deadeyes and lanyards for this stuff. Can you imagine deadeyes on a BCC…oh sweet! They make machined aluminum ones, but you can use the wood ones too. This stuff can not take a staylock or swage. You can also use turnbuckles if you wish.

  3. Large savings in weight aloft. My rig is 5/16 316 w/splices. Using this line (it floats) will cut out 65lbs aloft from my rig. Jeez, I’m getting so excited I’m starting to wiggle. This will be a HUGE boost to the performance of the boat.

  4. Very high chafe resistance. They use it for butchers aprons and drag lines on fishing boats. You can read more in the links I’ll post. One guy is a commercial fisherman, after using the line for 3 years and seeing how well it held up he decided to rig his trimaran with it.

  5. They are still testing the UV resistance. Right now they feel it will be well north of 5 years. But it is so inexpensive and easy to splice up yourself, doesn’t seem to be a prob. For me here in the salty/sunny Caribbean I won’t have to worry about corrosion. Also no fatigue.

  6. It stretches less than wire. but there is “creep”. So for the first year you would have to tune 2-3 times, but then it would be fairly set. Then maybe once a year. Need to do a little more research in this area.

Here are some links:
This is the forum over at Brion toss’s website.

Colligo Marine. They make aluminum deadeyes and have info on Dynex Dux.

Here is the website for Samson who makes the Amsteel Blue.

And a great thread on the stuff at the cruisers forum.

So here is my final solution. Going to re-rig with the Amsteel. Then I will get a ring for the sprit. Have Amsteel luff lines sewn into all three of my sails. Use a 2 part purchase on the jib with a low stretch halyard to a winch. I should be able to haul that puppy up tight. I can do all this for the cost of a good furler.

Anybody wanna race?

Good info Gary, I’ve been following along with the Dynex Dux/synthetic standing rigging too… Interesting. There’s a guy here who on MV who is going to use it for his motor sailor, since it will be much easy to lower his rig with rope vs wire. What’s the latest word on an accidental knife blade or similar sharp object running across this stuff? I recall that was an issue being discussed. I too was reading some of that cruiserforum thread just the other day.

Let’s chat about the bowsprit ring further, I will be looking into it myself for the future and will be happy to let you be the guineau pig. Are you and I the only boats without a roller furler and (currently) spliced rigs?!

Hi Ben,
Maybe…:sunglasses: It sure is a secure rig! From my reading…now I’m am not sure on this, but it seems I could get as much as 3 tons more righting moment, Going the the Amsteel. Thats 65-70lbs out of my weight aloft.

I’m a little concerned about getting to big a ring and have it distort under load. It would be nice to slip it over one end or the other with out taking off hardware.

Keep in touch. I will post to this thread my journey and at a thread I started over on Sparetalk

Just a quick note. I’m finding the Amsteel and the Dynex Dux are NOT the same thing. It appears they do not heat and pre-stretch the Amsteel. That probably accounts for the difference in price.

Also finding that you size this stuff for creep, not for strength. The strength is off the charts anyway.

Go to the link for Colligo above and read their news letters off on the right of the page. Here is where you will find the most info and tech stuff.

Ben, re: sharp knife. As I understand this it is not easy to cut. The fishy guys have used it very successfully, which is a much harsher environment than us sailors. They also use this material for butchers aprons. So I would think it would have to be a concerted effort with the knife. Or just don’t sharpen your knifes…

More information. I have found a table with specs on wire vs Dynex. Also I put together a little price comparison and initial estimate of overall cost.

Anybody have some settings for their rig using a Loos gauage? Particularly a 1/4 -9/32 combo.

For some reason the chart attachment disappeared when I edited my last post. I didn’t actually put this information together myself. This information is from

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 stay. I will stay with wire in Bobstay because of anchor/chain chafe.

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

Then I will use this black line for the lashings. 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!

The to finish off I will rig a bowsprit traveler from Classic Marine.

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.

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


Interesting to note that the only BCC I ever sailed was Shanti - so you say she felt heavy aloft, meaning she went over early, that was something I noticed and surprised me.

With the ring on the sprit, how far back can you get it? I recall Shanti didn’t have any anchor rollers out the sprit and the anchor stowed hard against the bobstay. I would guess that with any kind of anchor roller/fairlead on the sprit, you wouldn’t be able to get the ring far enough aft to work the sail from deck. And how does the ring handle the change in shape where it goes square. Does anyone suggest teak rub strips on the bottom of the sprit too aid in sliding, and paint/varnish chafe avoidance?

$4k for ring, dynex, deadeyes/lanyards and furler? That seems pretty good!

Ben, I just added bowsprit rollers…8-( . The 35 lb CQR rode right down at the water line on the bobstay. I think the traveler will come back far enough that I can access it from the fore deck easily enough. Although I have just replaced my primary CQR with a 22lb Delta. The shank on it is short enough that I could put it back on the bobstay and have it ride a lot higher. So now I have to decide if I want to take the sprit rollers off and sell them. I will try it first and see. Any way it will be a much improved and versatile set-up as opposed to going all the way out!

I will probaly take the sprit down to 8 sided just forward of the stemhead fitting. Details, details.

Just have to find 4k!!!


I have enjoyed this thread very much. I have three questions about your proposed rig:

  1. What is the life expectancy of the Dynex?

  2. How do you plan to prevent the bowsprit ring traveler from wearing through the varnish/paint coat on the bowsprit?

  3. What is the Dynex stretch factor as a function of time, i.e. will it continue to stretch over time?


Here are the answers to your questions. As I understand it.

  1. Right now the limiting factor is UV degradation. No fatigue or crevice corrosion to worry about. They figure that after all the tests are done (it takes time) the the life will be some where north of 5 years. They think it will be substantially north of that figure. This will be a % of strength lost over time. considering that the 9mm is over twice as strong as 9/32 wire, you would have to lose a lot to UV to even put it in the same ballpark as the 9/32 wire. Then you have to figure how much is left strength wise in the 9/32 wire over time to compare.

  2. Lots of varnish! Actually I will be using a 2 part varnish. But if I still have some problems I can tack some copper sheet where it wears. When was the last time you check someones varnish on the bottom of their sprit?

  3. Yes it will stretch over time. This is the creep factor I mentioned. Depends on the percentage of static load vs breaking strength. They say to size the Dynex for creep, as the breaking strength is more than you need anyway. And its so light. They also say to keep the static load to breaking strength less than 20% for manageable creep. I have sized my rig for less than 5% load/BS. This means that I will probably have to re-tune my rig a couple of times the first year and probably once a year after that. My creep should be in the neighborhood of 0.1 inches a year.

I realize this is all new technology. But the Dynex has been put through alot laready in the fishing and towing industrys. I will be eliminating some problems for others. But the savings in weight aloft will be something like adding 2 tons of ballast (thats just a guess!)

If you haven’t already, check my “Diameter” attacment above.



I know you are having fun doing this project but I think I will stick with steel rigging. There is no question Dynex has a high tensile rating. I believe we used a Dynex towing line on the tugs - very light, floats and it is strong.

I suspect you have considered using 1/2 oval brass under the bowsprit to prevent wear. That would be my choice instead of copper sheeting. OH, my 1st mate is very fussy about the condition of the varnish under the sprit.

I just looked at your photo site. You are good, no, your work is excellent. I know you have good equipment and nice glass but it is the 6" behind the camera that creates art and your work is art. Wow, I am impressed. I work in digital B&W trying to create fine art prints. Let’s say I work in digital B&W. I just purchased a used (370 images shot) Sony A700 with Konica Minolta AF 17-35 f:2.8 lens, Tamron AF 28-75 f:2.8 lens and a Minolta 70-210 f:4 lens. Now to see if I can still take photographs. My work does not compare to your beautiful photographs. I just self-published a book at BLACK & WHITE IMPRESSIONS by Rod Bruckdorfer | Blurb Books . All the work was shot with a Sony F828 digicam.

You may be interested in this site Wall art generator - Rasterbator . You can download a free copy of program to rasterize images to produce artwork up to 20 ft X 20 ft. It generates an Adobe Reader pdf file which can be printed on a simple inkjet printer or sent to a print shop, such as Kinko’s) for printing. I just produced a 17" X 17" print (4 sheets of 8 1/2 X 11" paper). I suspect Benjiwood will jump on this program and produce a full size poster of his boat. Check out the gallery at Homokaasu.

Enough photo geek talk. Sorry BCC forum users - a little off topic.

“Great Guns” I did a rough moment arm calculation to estimate how much ballast savings 70 lb aloft represents. My estimate is less than 600 lb. I did not use calculus to determine the moment arm, hence the number is probably more on the order of 300 lb.



Hi Rod,
Nice book! and B&W … keep it up. I use a program called Genuine Fractals. The Moorings are a client of mine and I did some 9’ tall prints for their new offices in Clearwater. Thanks for the compliments.

I didn’t do a mathematical on the righting arm. Couldn’t find out how on the net. I just guessed base on some article I read. It did seem a little high. Did some more research and found a rule of thumb someone was using that was 1 pound aloft was equal to 10 in the keel.

The reasons I’m so keen on this stuff is from personal experience while running a 78’ Ketch. The owner had me sail her to France so they could stretch her 10’ (don’t ask!). They were also going to have to put a bigger rig on her. At the time she was running Hood roller furling masts. I suggested the owner get Carbon fiber masts with full batten sails. HE DID!
I had left the boat for the stretch job. A year later he called me up and wanted me to take her to Belize/Guatemala for the season.
WOW…what a difference, and this was with a main mast that was 12’ taller! She didn’t roll any where near as much at anchor. Upwind she would take off like a witch, easily lifting over the seas and standing up proud. I was IMPRESSED! We removed something like 1600 lbs out of the rig. The Hood main mast weighed 2000 lbs. The new CF mast weighed 800 lbs. So you can see why I’m such a believer in removing weight aloft.

I am also in need of a re-rig. Mine is 12 yo. Also Shanti has stainless turnbuckles that are looking pretty bad. So the cost of switching to Dynex and the additional rigging parts is about equal. And I can easily do it myself.

Now I just have to figure out what I’m going to do about roller furling. I keep vacillating between a bowsprit traveler with a Code 0 furler or the Facnor STG furler. my concern now is how well it will sail to weather with the headstay sag I will have. I figure I can get about 600 lbs with using a Dynex luff line, 2 part halyard to a winch. If I wanted to go to a 2 speed winch with a higher power ratio ($450) I could theoretically get about 1200 lbs on the luff.

So I’m still stretching and scratching about all this. After all it is a big move.


Is there any reason why you could not employ a manually operated hydraulic cylinder to load up the Dynex luff line to 1,200 lb?

Thanks for the kind words about my B&W photography.



Rod, Just read an article about that, sorta. Seems what they use to do was haul the jib up with a 2 part halyard, then set the traveler outhaul up for the final tweak. You could use a hyfield lever for that.


Let’s assume you want a 1,200 lb load on the Dynex luff rope/jib stay.

Based on some quick trig, the horizontal load vector along the bowsprit is ~ 470 lb and the vertical load vector along the mast is ~ 1,100 lb.

It follows, the line that pulls the bowsprit ring traveler out must be loaded to 470 lb to equal a 1,200 lb load on the Dynex luff tape/jib stay. This assumes zero friction. Friction between the bowsprit and ring traveler will increase as the vertical load vector increases, hence more force is required to overcome the friction. Let’s assume a 200 lb force is required to overcome the friction between the ring and bowsprit, then a 670 lb horizontal load will be required to achieve a 1,200 lb load in the Dynex luff tape/jib stay. I question if this degree of loading can be achieved with a hi-field lever.

I still believe your idea is viable but your head sails will have to be cut to compensate for the catenary in the the dynex luff tape/jib stay. In the end, as is always the case with boats, it will be a compromise between windward ability of boat and saving weight aloft.

As you know, when a loose cannon flogs a dead horse there’s the devil to pay.



Thanks Rod, your da man!
Looks like the best way is to do it with purchase power and a 2 speed winch. Set the ring in place than crank that puppy up tight. I figure I will have to have the sails re-cut for the catenary. fortunately I have an excellent sailmaker/friend about a 1/4 mile by water from me. :smiley:

What about running Dynex on everything but the headstays?

It would not make any difference, the stay still has to be loaded up. I believe Gary is planning to have a fixed Dynex jibstay and one on the ring traveler. If he does not have a fixed stay, then the bobstay must be on a 4-part tackle.

The old English gaffers’ bobstays and whisker stays are setup with tackles, as is the stay fitted to the ring traveler. The old English gaffers set very large staysails and used the jib and topsail in summer winds. In the winter, the work boats would drop the top mast and bring the bowsprit inboard. These boats were true cutters. The BCC is a double headed sloop. Today we call any double headed sloop a cutter.

There are two definitive texts on sailing the old gafffers:

Classic Boat Seamanship by Martin Tregoning, ISBN 0-7136-3606-8


Hand, Reef and Steer by Tom Cunliff, ISBN 0-924486-40-6



That about it Rod. I will have a Dynex Headstay with nothing hanking on to it. Will be there just to hold the mast up. The jib and what ever sails I use will be set “flying” using a Dynex luff rope in the sail.

I still may opt out of the ring/flying combo and go with the Facnor STG furler. If I do that I will use there “soft” hanks. So far that has worked well for the boats that are using this stuff. If there still is a problem with chafe (I don’t think there will be as this stuff is sooo slipery) I can go to wire. One of the great things about this is the ease of replacing a piece of rigging if there is a problem.

ps…Ben, I posted an incorrect link for an articule on bowsprit travelers. Here is the correct link