Dyneema standing rigging and aluminum masts

[longjonsilver]

i would like to know from those that have dyneema standing rigging: What are your experiences tuning your rigging with temperature changes?

There are those that allege that since the coefficient of expansion/contraction of dyneema and aluminum are not only different but completely opposite (as it heats up aluminum lengthens and dyneema shrinks) that temperature changes cause dyneema rigging with an aluminum mast cause the rigging to go banjo tight or floppy loose. Is this your experience? And what kind of temperature changes do you experience in your area?

Thanks in advance

jon

[chrisr]

america's cup riggers i have spoken to tell me that dyneema rigging needs to be re-tensioned / re-set up every day...

cheers,

[Sailmonkey]

My only experience with dyneema standing rigging is a 22’ beachcat with a 45’ carbon mast, so not really apples to apples but....

The rigging was a royal pain to get setup initially, short sails followed by re-tensioning for two days. However once past that initial hurdle the rig stayed in tune just as well as the previous stainless rig. Again though it was re-set for specific wind speeds on some days for the most part is was left rigged for 2-3 months with no change.

[Orin]

Originally Posted by chrisr

america's cup riggers i have spoken to tell me that dyneema rigging needs to be re-tensioned / re-set up every day...

cheers,

Would they have been doing this with stainless rigging? Racers retune a lot.

[BillKny]

Speaking strictly as a cruiser here...

Let's agree to dismiss any comments from racers. Any racer who isn't tuning his rig AT LEAST once a day just isn't trying. Even on the yacht club circuit, a dedicated racer will have different wire tensions based on wind strength, so he is always changing the tension in his rig and will never see any temperature effect. I suspect the AC boats have rigging tunings that depend on how much the crew ate for breakfast!

I have actually rigged a 40 foot cruising ketch with dyneema. it worked out to about the same price as a stainless rig, and I was VERY happy with the performance difference even on a very none-performance driven boat. Less weight aloft==less heeling==less leeway==less reefing==better windward performance.

I think this thermal issue is a bit of a red herring.

The issue with rig tensions and thermal expansion is certainly theoretically correct, but will have relatively little effect on a real world cruising boat. Remember, that stainless and aluminum also have very different thermal coefficients of expansion, so this is not an effect that is qualitatively different to a standard rig, only quantitatively so.

Pre-tension in a rig does two things. It keeps the mast straight when it first loads up, and it prevents shock loading of the rigging wire. The first effect (unless WILDLY sloppy) is a performance issue, and not a huge deal to me as long as the mast stays "in column." The second effect is quite important with SS rigging, since work hardening is one of its early failure modes, and slack rigging adds a LOT to work hardening. For dyneema, I am not aware of any issue with cyclical loading, so if the rig goes a little slack on a cool day it's not nearly as big a deal.

Another thing to consider, is that you will be adjusting the tension in your dyneema rig a lot more than your stainless one. Dyneema "creeps." Under tension it gets longer with time. Note that this is different than "stretch" A spring stretches, and then goes back to its original length. A material that "creeps" gets longer, and STAYS longer.

I found that I needed to pull things a bit tighter every two months or so to keep tensions up. This effect pretty much overwhelmed any seasonal temperature changes.

If you want a "set and forget" cruising rig like a stainless one, dyneema is not for you. But you don't need to be compulsive about it either.

[TheOffice]

Did you use heat set Dyneema? It isn't supposed to creep, but costs more.

Originally Posted by BillKny

Speaking strictly as a cruiser here...

Let's agree to dismiss any comments from racers. Any racer who isn't tuning his rig AT LEAST once a day just isn't trying. Even on the yacht club circuit, a dedicated racer will have different wire tensions based on wind strength, so he is always changing the tension in his rig and will never see any temperature effect. I suspect the AC boats have rigging tunings that depend on how much the crew ate for breakfast!

I have actually rigged a 40 foot cruising ketch with dyneema. it worked out to about the same price as a stainless rig, and I was VERY happy with the performance difference even on a very none-performance driven boat. Less weight aloft==less heeling==less leeway==less reefing==better windward performance.

I think this thermal issue is a bit of a red herring.

The issue with rig tensions and thermal expansion is certainly theoretically correct, but will have relatively little effect on a real world cruising boat. Remember, that stainless and aluminum also have very different thermal coefficients of expansion, so this is not an effect that is qualitatively different to a standard rig, only quantitatively so.

Pre-tension in a rig does two things. It keeps the mast straight when it first loads up, and it prevents shock loading of the rigging wire. The first effect (unless WILDLY sloppy) is a performance issue, and not a huge deal to me as long as the mast stays "in column." The second effect is quite important with SS rigging, since work hardening is one of its early failure modes, and slack rigging adds a LOT to work hardening. For dyneema, I am not aware of any issue with cyclical loading, so if the rig goes a little slack on a cool day it's not nearly as big a deal.

Another thing to consider, is that you will be adjusting the tension in your dyneema rig a lot more than your stainless one. Dyneema "creeps." Under tension it gets longer with time. Note that this is different than "stretch" A spring stretches, and then goes back to its original length. A material that "creeps" gets longer, and STAYS longer.

I found that I needed to pull things a bit tighter every two months or so to keep tensions up. This effect pretty much overwhelmed any seasonal temperature changes.

If you want a "set and forget" cruising rig like a stainless one, dyneema is not for you. But you don't need to be compulsive about it either.

[longjonsilver]

As i understand it, Colligo marine uses Hampidjan dyneema, and they are just down the road from me.... https://www.hampidjan.ca/

The boat i am looking at has 30 year old standing rigging, and altho she was rigged with one size up all over, i think it is high time to rerig her....

And yes, SS and aluminum have different coefficients of expansion also, but as i understand it, dyneema expands when it gets colder and contracts when it gets hotter, the exact opposite of metals, like aluminum....

The theory is that wooden or carbon fiber masts are great with dyneema but not aluminum masts.

The rigger down the road estimates $500C per wire, n i have 11 wires plus runners...

jon

[alaskanviking]

i have Dyneema rigging on an aluminum mast. i didnt do too much before trucking it to the east coast so the rig was up ~ 7 months.

i researched dyneema rigging religiously for years before doing it on my boat. while i have seen the temp expansion/contraction info you posted before, only recently. i dont remember seeing anything on this prior to maybe this year.

i can report that the majority of conversions are with aluminum spars, including mine. i have yet to see any issues with contraction/expansion. thats a lot of boats, and includes earlier days when everyone was skeptical and almost looking to find issues with the material.

ONLY use heat set dyneema Ie Dynice Dux for rigging. heat set dyneema does creep but you size the diameter of the line for the creep so that you lose maybe 1/8" a year or so under the loads and tension of your rigging. Coligo and others have calculators and charts to figure this out.

I also advise adding a dyneema chaff sleeve on to the stay/shroud while splicing. they have gotten figures of 10 years in the sun, but a chaff sleeve will help extend that. i suppose you could get double braid dux but not many have access to it, and i suspect its probably a pain to splice and tension. single braid with brummle splices are really easy and the splice locks itself together.

[blubaju]

"america's cup riggers i have spoken to tell me that dyneema rigging needs to be re-tensioned / re-set up every day..."

Being a lazy cruiser I've never done that. If to much slack we reduce, just to take the banging out, well, it is a Schionning Cruising Catamaran, the always have slack ;-)

18.5m rotating carbon mast, now in its 11 year, Outer shrouds 1x changed, still tested 5t, then came Covid...

Altogether I am very happy with Dyneema stuff, fittings all home brew.

[longjonsilver]

Originally Posted by blubaju

Altogether I am very happy with Dyneema stuff, fittings all home brew.

Can you show me pics of your homebrew fittings? i plan on doing the same, the rope is relatively cheap, but the fittings are not. Yet, what can be so hard about machining a bar of aluminum?

jon

[kryg]

It's normal to worry about changing your rigging from wire to Dyneema, I found one is worried about detailed fractions, which have no issues over all. Most important, is the weight savings. Because I found a rigger that knows what his is doing in Dyneema. All these worries disappeared after a robust Q&A.

One year ago I change all my standing rigging and safety lines to Dyneema, weight savings was about 250 kilos. The weight of the Dyneema replacement rigging only 30 kilos. That is a big number that matters. I will never have Stainless wire rigging again. My mast at 18 meters is Aluminium I have had not a single issue of concern that could be measured.

Attached are photos of a Pro-Dyneema rigger working on re-rigging my mast with Dyneema replacement.

After my experiences of possibly considering re-rigging it myself, (glade I didn't) or contracting a rigger who normally works in wire rigging (again Glade I didn't). I can't stress enough it is important to find not any wire rigger but a very experienced Dyneema Rigger, this is a Must!

Photo of NZ made turn-buckles and 30 kilos of Dyneema replacement all standing rigging but the forestay which is wire as I have a roller furler.

Good luck with your rigging replacement, Your journey of questions ends when you find a rigger who knows what he is doing.

SV Skoiern IV - Kryg

Originally Posted by longjonsilver

i would like to know from those that have dyneema standing rigging: What are your experiences tuning your rigging with temperature changes?

There are those that allege that since the coefficient of expansion/contraction of dyneema and aluminum are not only different but completely opposite (as it heats up aluminum lengthens and dyneema shrinks) that temperature changes cause dyneema rigging with an aluminum mast cause the rigging to go banjo tight or floppy loose. Is this your experience? And what kind of temperature changes do you experience in your area?

Thanks in advance

jon

[blubaju]

Originally Posted by longjonsilver

Can you show me pics of your homebrew fittings? i plan on doing the same, the rope is relatively cheap, but the fittings are not. Yet, what can be so hard about machining a bar of aluminum?

jon

deep groove for protection. These are multipurpose, the 2 upper holes for security strings. Here used at the shrouds with a 1:8 purchase, all heavy & expensive turnbuckles gone.

Did not find a reliable company for anodizing. so sanded, epoxy primer coated before oxydation, even sanded into the wet epoxy and second coat polyurethane paint, lasted 10+ years now, some blister spots appearing. Basically same method the mainsail track is glued to the carbon mast

The lower ones are simple sheaves in stainless. Stainless bcs the axle is stainless and there is no galvanic corrosion. Diameter could be larger, but the boat design was originally for stainless rigging.

Why the rope so much longer? Did not have any idea about the stretch to expect and for tensioning you need some rope to hold on. After many years, rest assured, it is very easy, just go sailing, the lee shrouds are loose anyway.

Sorry for the late reply & good luck for your project ;-)