Dyneema Shrouds and Splicing

[Craic]

Tony,
yes, the wrong one is wrong and the one with the question mark is the correct one.
A bit tight when you have to get the hard eye of the shroud end you have done first through the strands, but it does work. The needles are so smooth they help widening the gap in the strands.
The hollow needle splicing tool is also great for burying the loose end inside the standing part, you just tuck it in and slide it on inside the standing part, loose end in tow.

[Michael Rogers]

Hi Guys. What is the problem with clapping on a seizing, either using a thimble or to form a small 'naked' loop? I'm not scoring points here, but asking because I'd like to know! It's my preferred method with braided rope anyway, and if you take a bit of care, use fine whipping twine and put on the extra frapping etc turns (my copy of "Marline Spike Sailor" hasn't surfaced yet after our move, and I can't remember all the jargon), the result is v neat and v strong. Isn't it?

I got some grey plaited 100% Dyneema from Mailspeed Marine yesterday (LOVELY stuff in the slippery stakes!), and I've tried a seizing. It works fine, and round a thimble there would be no kinks or v small radii to weaken the rope. As a hitch a constricter knot also seems to hold, especially if one uses two riding turns.

On the subject of breaking strains, isn't it true that for most uses in our kinds of sailing, ropes parting because of overload is almost never a practical issue? (Shrouds are an obvious exception with special considerations, and I know this is where Claus came in in the first place, until I caused a diversion!) Halyards and sheets are the thickness they are for ease of handling, not because they need to be anything like that strong. The Newlands were entirely logical in this respect with their practical attitude to the jib sheet once the loading had been greatly reduced by using club booms on the Storms etc.

[Tony]

Hi, Michael.
Nothing wrong with a good, tightly whipped seizing,  so long as the whipping twine bites deep enough  into the material in use to make sufficient friction, thus keeping it all together. (As you point out, the frapping turns are important in this respect).
The only problem with Dyneema is that it is both hard and slippery, making this difficult.
If it holds, great, but the amount of grip the whipping has on the Dyneema  can only change for the worse.
The beauty of the splice that Clause uses is that as the tension increases the splice grips ever harder! With enough bury there is also a much larger  area of frictional surfaces in contact – which is why splices of all kinds are generally  preferred to the equivalent knot or seizing.

Why do I still use a scaffold knot when making a hard eye?   
Three reasons.  No tools required;  it takes only seconds to tie; I trust it to work.

However, where it REALLY matters (eg  anchor chain to warp) I take my time and use a splice!

[Michael Rogers]

Tony, all points taken with thanks. I must add a scaffold knot to my repetoire.

Emphasising that shrouds are a special case (I must look up the etymology, if it is known, of the use of the word shroud in this particular nautical context), in other rigging situations I still think a sense of proportion is needed - horses for courses, to mix a metaphor or two. If Dyneema is ten times stronger than polyester, and putting a bowline in it halves its strength, it is still five times stronger than polyester! In any case, as I indicated before, my personal use of Dyneema will be limited and specific, and I doubt if sudden failure of a luff-hauling parrel would ever be catastrophic in its consequences

[Julian Swindell]

Question for Claus. How do you finish off the other end of the shroud, down at the bottom? I think they generally use a modern deadeye system. How do you fix to that, as you cannot form another eye in the other end the same way can you?

[Craic]

Question for Claus. How do you finish off the other end of the shroud, down at the bottom? I think they generally use a modern deadeye system. How do you fix to that, as you cannot form another eye in the other end the same way can you?

Julian,
you can have hard eyes on either side, surprisingly you can widen up between the strands enough to squeeze the hard eye done first through.

Though,
I think the hard eye is not even necessary. The next shrouds I'll do I will leave the hard eyes out.

Good luck,
C.

[Julian Swindell]

I have just got some dyneema shrouds for my BayCruiser and I am intrigued by the whole idea of non-metallic rigging. Regarding the splicing kit at the start of this thread, the special splicing tools are just locking forceps, which you can get from most toolshops eg
http://www.axminster.co.uk/product-Electro-Locking-Forceps-20071.htm
Has anyone used the modern deadeye system rather than hard eyes and lanyards or rigging screws?
http://www.precourt.ca/
Or the dyneema soft shackles, which seem a good idea but amazingly expensive. £24 each on ebay!
BTW I did a google search on dyneema shrouds and it came up with this threaad as the first hit!

[Julian Swindell]

Following on from the last, have a look at this mind boggling way of doing an eye splice in dyneem when you can only get at one end of the rope. I think I can just about figure it out, but I don't have the nerve to try. They call it the Moebius splice with good reason
http://www.precourt.ca/brummel_splice.pdf

[Craic]

Following on from the last, have a look at this mind boggling way of doing an eye splice in dyneem when you can only get at one end of the rope. I think I can just about figure it out, but I don't have the nerve to try. They call it the Moebius splice with good reason
http://www.precourt.ca/brummel_splice.pdf

Julian,
there is a trick.: You do not put in the hard eyes before you have prepared BOTH ends of the shroud. That way it is much easier to pull the second end through the strands of the first end.

[Craic]

Just to report back after more practical sailing experience this year.:
The Dyneema shrouds were a complete success. I have full confidence now after somel heavy weather sails with full crew sitting on the gunwhales. I had marked all splicings to check for slip, but none occurred. The hard eyes are sitting tight. No major chafing.

I have it on all boats now, and the splicing gets quicker with more practice.

When we were in Venice, most other boats had it as well.

Recently I used some leftover to replace the steel wire of our garage door opener which had broken, perfect.
Go for it!

[Julian Swindell]

I would agree with Claus. I have had dyneema all season and had no problems at all. They are a positive benefit when de-rigging to tow home. It is much easier to coil up the dyneema and stow them out of the way than wire, which always kinks and uncoils. Also, when I messed up coming alongside a pontoon at Bucklers Hard, I saved myself from falling in by doing a complete 360 degree pirouette round a shroud, much to the amusement of my daugthter. If I had been clutching wire, I think I would have cut my hand and fallen in.
I still have a wire forestay and am wondering whether to change that to dyneema. Obviuosly not a factor on the balanced-jib Byaraiders. what I would really like is to have a dyneema forestay with those neat little plastic deadeyes you can get from Precourt, but they are so expensive for two bits of plastic I can't bring myself to do it.
http://www.precourt.ca/

[Guy Rossey]

In connection with shroud tension and lanyards, I learned that the mast of a recent BR (2010) fell down because his original (polypropylene ?) lanyards broke in a gust. I thus changed mine with Dyneema lanyards. Do some of you have more experience or comments on their behaviour in both material on the long run? Thanks
Guy
BR Catchando Bay

[Craic]

... Do some of you have more experience or comments on their behaviour in both material on the long run? Thanks
Guy
BR Catchando Bay

Guy,
lanyards breaking in a gust, mast coming down, the horror.
Could have many reasons. Chafe, splice, too few turns due to forward mast rake?

It is not so much the lanyard material that matters -PP is fine BTW- but how it is done, and how it is maintained. I myself am using 2-3 mm Dyneema core material with a woven outer, and 4-5 turns min. I find material with a woven outer is slicker so it spreads the load better between the turns. No absolute need for Dyneema really, more important is an even spread of the load.

Lanyards are a consumable BTW, Cheap, and simple to replace.
I know the boats come with spliced PP lanyards, as is good boatbuilder practice. But today most people cannot splice, so they shy away from cutting the original lanyards off in order to use new material with a bowline knot instead. Wrong respect.

[Guy Rossey]

Thank you for your helpful comments, Claus .
Yes, several reasons could account for the failure of these lanyards. However and even then, the alerting signs are not always obvious and I wonder if PP is really enough here.  I experienced myself the breaking of the collar ( same PP)  securing the gaff on the mast, after some excursions. Here also it might have been due to too much torsion on the gaff or some mishandling of mine but I changed this now for Dyneema and I sleep better. Nevertheless, I understand from your posts that the way these Dyneema ropes are fixed is of importance as well.
Guy
BR Catchando Bay

[Craic]

Guy,
you can use shoelace or sewing thread for lanyards. As long as you give enough turns i.e. loops to build up a combined tensile strength of the lanyard connection which -at least- matches the tensile strength of the shroud.

Different with your single collar rope. There you cannot do loops. I have seen that break a few times, usually where it has been rubbed thin by edgy hole rims of the steel jaws. No big deal.