An alternative method for tensioning dyneema rigging

[peb]

I came across this page the other day:

https://www.riggingdoctor.com/life-a...pass%20through.

Note: I am not endorsing the rigging doctor, I have mixed feelings on some of his stuff. However, this seemed rather interesting. It is using a Gallagher inline electric fence tensioner to tighten the lashings on dyneema rigging. In the article, it says they are plastic, but the ones I have seen in the past and online are aluminum.

At first pass, this seems like a really good idea. It provides a solution to some of the common problems with lashings. It allows the shrouds to be properly tensioned without a lot of fuss with halyards and winches. It seems like it would be much faster to tune the rig than just lashings alone, since one would not have to mess with tying off the lashings. Finally, it would allow the legs of the lashings to continue to equalize, since there is no tie off which inhibits further equalization.

But when something seems too good to be true, it usually is. So I am wanting to see what the folks on this site think of the idea.

[catsketcher]

Thanks for that. A quick check had me finding some aluminium ones at about 6 euros each. Great idea.

[Franziska]

Thanks for sharing, had I known this earlier I might not have added the bottlescrews...

[fxykty]

This is an awesome idea.

I’m wondering whether a ratchet driver would work for the square hole - that would save getting another tool. Would that provide sufficient leverage?

How sharp a corner does the captured lashing turn in the fitting? It doesn’t much matter for wire, but Dyneema certainly doesn’t like sharp corners. Could you pad the slot edges where the captured lashing enters/exits the slot?

Would it work best by capturing a middle lashing so that there are equal numbers of lashings on either side, or does that even matter?

[peb]

Originally Posted by fxykty

This is an awesome idea.

I’m wondering whether a ratchet driver would work for the square hole - that would save getting another tool. Would that provide sufficient leverage?

How sharp a corner does the captured lashing turn in the fitting? It doesn’t much matter for wire, but Dyneema certainly doesn’t like sharp corners. Could you pad the slot edges where the captured lashing enters/exits the slot?

Would it work best by capturing a middle lashing so that there are equal numbers of lashings on either side, or does that even matter?

I went ahead and order a bag of 10 of these gizmos off of Amazon. I hope to have a morning later this week or early next week to do some testing. So far, I can tell you that the slot is just wide enough for 3/16 amsteel to fit into it. There are some edges along the slot that can cause the line to snag a wee bit when removing it. But nothing too bad. As for the edge where the line exits the slot and starts wrapping around the cylinder, it is smooth, but a tight turn. I would guess a radius of under 1/8 inch. I will measure it when I get to the shop tomorrow, but it certainly looks like the sharp radius won't necessarily change the lashing line, but it will reduce the strength of the lashing line on that leg significantly. A bigger problem is that the slot is not really deep enough to fit 2 3/16 amsteel lines into it. You can, but it is not very pretty. I was thinking one would terminate both ends of the lashing at the tensioner for a really clean solution, but I am not for sure that will be possible.

I can fairly easily set up a test system for 4000 lbs in my shop. I will initially tighten it with a 1/2 drive ratchet or break-over and via a load cell let you know how much pretension one can achieve with it. Then I will tighten it up to the 4K load. May do the latter on a lashing of only 2 legs to get a feel for how it holds up under 2000 lbs. That will be about the best I can do testing.

All-in-all, looking at one in my hand, I think it is an idea with a lot of potential, to the extent that the lashing vs turnbuckle argument could be a thing of the past on many boats. But, as one would expect when applying a device to an application it was not intended for, the details are not quite there (doesn't mean I won't use it on my 25' gaff rig), and it would be really nice if someone (ie Colligo) would develope one specifically for the sailing market. I suspect it doesn't need many changes to work really well.

[Franziska]

Just a thought, these gizmos look fairly simple.
Should a stainless steel workshop not be able to make a few long-lived ones of these for a price far less than turnbuckles?

That is, if one is concerned about longevity of the plastic or aluminum versions due to the marine environment.

[peb]

Originally Posted by Franziska

Just a thought, these gizmos look fairly simple.
Should a stainless steel workshop not be able to make a few long-lived ones of these for a price far less than turnbuckles?

That is, if one is concerned about longevity of the plastic or aluminum versions due to the marine environment.

They are a little more complicated than they appear in the pictures due to the slot that is machined in part of the axle and the inset square for the wrench to be used. That is due to their application of putting them on an existing fence to tighten it. They could be much simpler for our application, as they would not need to work for an existing continuous linse, but simply a whole in each disk for each of the two ends of the lashing to be fed through and a stopper knots to be tied. Indeed, that is how I may end up using these. And yes, it does seem like that type of device could be easily manufactured.

But I keep thinking there must be a reason as to why this has not yet been done. This type of rigging has been aroudn for 10 or 15 years and the lashing is the one difficult part. If it allows elimination of a turnbuckle, that is a significant cost savings on installing synthetic rigging. Significant, good turnbuckles are the most expensive single part in standing rigging.

[AKA-None]

I was never happy with the plastic ones when used with actual fencing wire
The wire would cut through by distorting the plastic
It may work for you

Edit
Replace before they start to look bad, they will distort under pressure

Waiting to see what the testing shows

[peb]

Did some testing. Failure. Do not consider doing!!!!

Details: I a 3 loop lashing around 2 sailmaker thimbles, one side anchored, the other side with a load cell. I terminated the two ends at the tensioner. One end I had done an eyeslice that went through the slot on the axle. On opposite side of the tensioner, I drilled a hole through the disk at the axel to allow the other end of the lashing to go through and I put in a stopper knot. It wasn't the best solution, but I was able to tension the overall line to 300lbs with a 14inch breakover socket. Wanted more, but I needed to come up with another way of doing, likely tying off the two ends at the thimbles and using the tensioner as designed. Seemed like the whole idea had promise. But I went ahead and decided to tension the "shroud" (on the other side of the load cell, I had a 4 ton come along. I tighted it to around 2500lbs of load. assuming an even distribution, that should have only put around 400 lbs of load on the tensioner. Not that much. But it broke. The disk on the side snapped off from torque that was placed on the holding pin which went around the lines. That torque would actually be quite high, IMO.

Its a shame, because I thought it had potentional. I still do, but someone would have to make a purpose built tensioner specifically for this application IMO. Yea, my set up for terminating the lashing ended up not being quite right, but lots of things at sea, with dynamic loads also don't end up quite right. I won't be using these fence tensioners. No needs to try anymore IMO.

Oh well, only cost me a couple of hours of work and $30 bucks.

[Franziska]

Originally Posted by peb

Did some testing. Failure. Do not consider doing!!!!

Details: I a 3 loop lashing around 2 sailmaker thimbles, one side anchored, the other side with a load cell. I terminated the two ends at the tensioner. One end I had done an eyeslice that went through the slot on the axle. On opposite side of the tensioner, I drilled a hole through the disk at the axel to allow the other end of the lashing to go through and I put in a stopper knot. It wasn't the best solution, but I was able to tension the overall line to 300lbs with a 14inch breakover socket. Wanted more, but I needed to come up with another way of doing, likely tying off the two ends at the thimbles and using the tensioner as designed. Seemed like the whole idea had promise. But I went ahead and decided to tension the "shroud" (on the other side of the load cell, I had a 4 ton come along. I tighted it to around 2500lbs of load. assuming an even distribution, that should have only put around 400 lbs of load on the tensioner. Not that much. But it broke. The disk on the side snapped off from torque that was placed on the holding pin which went around the lines. That torque would actually be quite high, IMO.

Its a shame, because I thought it had potentional. I still do, but someone would have to make a purpose built tensioner specifically for this application IMO. Yea, my set up for terminating the lashing ended up not being quite right, but lots of things at sea, with dynamic loads also don't end up quite right. I won't be using these fence tensioners. No needs to try anymore IMO.

Oh well, only cost me a couple of hours of work and $30 bucks.

Uups. Not good. Sort to hear that.

Get one made of stainless please and give it another shot.

[peb]

Originally Posted by Franziska

Uups. Not good. Sort to hear that.

Get one made of stainless please and give it another shot.

Not really my cup of tea. I would prefer a professional design one purposed for this application and have it fabricated and do some better load testing than I am setup to do.

But I wish someone would, I think the idea has potential and it could really be a useful piece of kit. Perhaps I will send the idea to colligo marine. They could make them and charge 100 bucks a piece (cheaper than rigging screws) and sell quite a few.

[Benz]

It is really really easy to lead the fall of the lashing to a come-along, attach the other end of the come-along to a halyard or a piece of line hung from aloft, and get all the tension you need without having to lead the lanyard in all sorts of directions that are not the direction of pull. There's an advantage to keeping the pull inline: if nothing else, because you're not turning unnecessary corners.
I have just tuned my synthetic rig by tightening the lashings by this method, and found that I had to go easy on the come-along lest I get too much tension. The come-along was $40 at Home Depot.

[peb]

Ben, thanks for the response. I have never had a problem in my last boat getting proper tension on my rig. I don't expect to this time either. It will be a bit different without a winch, but a come along/handy-billie will work fine. I was just wanting (hoping?) for a solution that was less time consuming. To be clear, I wasn't even looking for a solution, didn't even think it was a problem, but just stumbled across this idea and it got my mind working.

BTW, thanks for those instructions on the covered eye-eye loop. Much better than my previous way of making them and I am using them quite extensively on my new rig. Very helpful.

[Franziska]

Originally Posted by peb

Not really my cup of tea. I would prefer a professional design one purposed for this application and have it fabricated and do some better load testing than I am setup to do.



But I wish someone would, I think the idea has potential and it could really be a useful piece of kit. Perhaps I will send the idea to colligo marine. They could make them and charge 100 bucks a piece (cheaper than rigging screws) and sell quite a few.

Fair enough.

Don't get me wrong in the following I appreciate your testing and thoughts.

Just hope someone else does it instead of a company slapping an expensive "marine" price tag on it and then trying to get it patented.

If the original is really 5$ I would not think 100$ is a reasonable price tag even if it's from another material and someone ran a few calcs on it.

[peb]

Originally Posted by Franziska

Fair enough.

Don't get me wrong in the following I appreciate your testing and thoughts.

Just hope someone else does it instead of a company slapping an expensive "marine" price tag on it and then trying to get it patented.

If the original is really 5$ I would not think 100$ is a reasonable price tag even if it's from another material and someone ran a few calcs on it.

Yea, I get that $100 is expensive, I was just imaging what colligo would likely charge. OTOH, in a case such as this, I can kinda see why it would be that price. Takes a fair bit of engineering work and tooling to put into production even simple parts, then one has to test the prototypes and deal with liability insurance. All this for a pretty small market base. Also seeing as the main competitor are turnbuckles, and those things are not cheap.

But yea, I would love to go buy 9 of them for $10 a piece. I would likely be willing to pay more if they really worked and one did not have to deal those frapping knots (or whatevery they are called).