Using dyneema for rigging - warning

[Robert Sheridan]

We had a go with a dyneema bridle for our Tiki 30 at the suggestion of the rigger as it is hard to make up hard eyes on 6mm wire. The dyneema stretched really badly the first time out, we retightened and it stretched again (to such an extent I had to set up the spinnaker halyard as a forestay) so we are going to go back to wire.

We have since found out that there are forms of dyneema that 'creep' less than others, but it all creeps to some extent.  The stuff we had was apparently from Liros and the supplier is getting back to them.

So.. if you are thinking of using modern braids for rigging check their stretch and uv characteristics  very carefully before buying and also make sure you are supplied something with a cover to protect against abrasion.

[Éric Bouvéron]

I made some deadeyes out of marine plywood and epoxy, and ask opinions here about them. Very negative.  Not strong enough. Didn't dare to use them. Easy to make thought.

You may use three layers of strong wood. the middle one slighty smaller. Choose the thickness according to you shrouds. Glue the and put some metal or wood pins to reinforce the final piece. make three holes, one "flat" (that where the lashing start with a knot), the other with an angle to put less stress in the lashing.   Then try to see how strong it is...

However, may be with some more solid wood, it would be also possible. A little higher in this post, Ian R made a nice job. 

One advice, I believe that if  you make them out of wood, you have to put the fibers of the wood in the same direction as the shrouds. I never used one but may be a router could be a good help to shape the wood.

Keep us informed. I'd love to see the results. Good luck

[john james]

I am using dinema for shrouds and I'm wondering if the shroud length as stated in the plans is going to be ideal for lanyard application. I'm thinking they may prove long considering these stated  lengths are likely designed with turnbuckles in mind.

[boatsmith]

measure the total shroud length and allow 24" for deadeyes and lanyards

[john james]

Thank you boat smith but deadeyes and lanyards are not in my future at the moment I was planning simple whippings through shackle at chainplate and stainless steel eye on shroud. Getting anxious to see it float.

[andy solywoda]

Ahoy JJ,

     I think using deadeyes is necessary, my lashings failed and I used shackles and eyes with SS thimbles.  I've now gone back to turnbuckles.  I am using nylon mooring thimbles on 1 shroud to insulate it for use as a SSB aerial.  I will see how that holds up.

Fair winds,

Andy

[Éric Bouvéron]

John,

You may go with simple lashing.

My recommendation here is the way to lash.

Please have a look to my poor designs, if it is not clear enough I will make picture of the actual thing during the week end.

The idea is go out of the eye at each turn, around your chainplate, and do the same on the other side. You give much more tension to your job. Try to picture your lashing as a "V" instead of a "A".

At the finish, you have to cross the rest of your line at each, it will block it like a splice. Well, almost. Anyway, it will not slip.

Good luck!

[john james]

Can anybody tell me about how much space the plans have aloud in their measurements of shrouds --between chain plate and the eye of the shroud??

[Björn]

Do you have any more what failed and why, maybe some pictures?

Björn

andy solywoda said:

Ahoy JJ,

     I think using deadeyes is necessary, my lashings failed and I used shackles and eyes with SS thimbles.  I've now gone back to turnbuckles.  I am using nylon mooring thimbles on 1 shroud to insulate it for use as a SSB aerial.  I will see how that holds up.

Fair winds,

Andy

[andy solywoda]

Ahoy Bjorn,

     I wrote up everything in my blog, address is on my page, I think I did something wrong, the lashings worked for years, then I had the mast come down and I thought it was UV damage.  Then I had all the lashings that had a load on them fail in storm conditions.  Every one of them failed except the middle bridle lashing, and it only carried a portion of the bridle load.

     Now we have a legitimate ship's rigger in the boatyard and he says the deadeye's were used in the old days to prevent chafe of the lashings against themselves.  My lashings were on SS thimbles and it was possible for a loop of lashing to slip off the thimble and chafe on the rigging wire or even get pinched somehow.  I really can't recommend how to rig a boat up with lashings.  Also I am using SS chainplates, not the Tiki style, which have a large radius and look like they will not cause chafe.

     I really like some of the input, like from Boatsmith, and others, who are trying out some of these schemes and providing the rest of us with the results.  The many requests for details about beam lashings and non-metal rigging means the information is not readily available, so it would be great to put something together here.

     The Wharrams seem to have been designed not so much to outperform anything else, but to out-survive anything else.  With any other boat neither I or the boat would still be here.  But it can be made better.

Jibing Downwind,

Andy

[Robert Sheridan]

We have over size thimbles and large bow shackles.  I tried using very thin covered spectra and lots of turns and found that it chaffed through and I suspected wear on the thimbles.  Using larger diameter lines, previously pre-stretch and now dyneema, we have not had the same problem, the lashings are very tight and frapped; however, we also do not get to use Mango much at the moment (work).  We were planning on making delrium (if I have spelt it correctly) deadeyes but time has not been available.

andy solywoda said:

Ahoy JJ,

     I think using deadeyes is necessary, my lashings failed and I used shackles and eyes with SS thimbles.  I've now gone back to turnbuckles.  I am using nylon mooring thimbles on 1 shroud to insulate it for use as a SSB aerial.  I will see how that holds up.

Fair winds,

Andy

[andy solywoda]

Here's the thimble I used on my insulated shroud:

I wasn't against using lashings or soft rigging, but after failures I had to retrench.  Obviously it is my method that didn't work out.  It worked OK until conditions got bad, then they all failed.  I'll see how this plastic thimble does.  I would need to go on a 35 knot downwind run to duplicate the conditions.  It was fun while it lasted.

[andy solywoda]

Here is a photo I shot when the Nina and Pinta were in town:

There is a whole album on my flickr page, just search kaimusailing ...