Dux Rigging - Turnbuckles and or deadeyes

[Joe Henderson]

Dear Rock,

Correctly selected turnbuckles are fine with the new Dyneema types recently developed by companies like Hampidjan, and more recently, Marlow in the UK.

I attach pictures of the Dynex materials fittings we have made in preparation for the re-rig, in Dynex Dux with overbraid, of the 120 foot schooner SOUTHERN CLOUD here in Sydney.

With care, a bit of application and the assistance of a gifted machinist, I arrived at a set of bobbin thimbles that are of a size that fit into the slightly modified mast tangs and turnbuckle jaws.


Everything I have seen and tested and broken over the last 25 years that I have been supplying and using lines and tendons in Spectra/Dyneema leads me to the conclusion that, providing your sizing and end treatment execution are competent and considered, you do not need the huge bending radii that some components on the market exhibit.


The dead-eye and lanyard type thimbles/connectors/what-have-you that are available from Colligo and Precourt, amongst others, are nicely machined and finished but seem to be more suited to do it yourself types of installations or multihull applications, and the like, where the boat often moves more than the rigging, rather than narrow-angled rigs on keelboats.

( Having said that, I used them succesfully in the (not particularly narrow angled ) rigging that Mike Strong supplied to Nacho Postigo's boat as featured on the Colligo website, but that was a while ago and I still think that boat would have been better served if I had insisted on turnbuckles and bobbins. )


For tension members supplied to the aforementioned keelboats and other projects on a commercial basis that I am willing to stand behind ( no pun inteded ) I use either widely available heavy stainless thimbles from Crosby et-al - which I modify - or my own manufacture of bobbin thimbles (in a variety of materials, depending on duty ) fitted into standard turnbuckles and tangs.


At the other end of the spectrum, we are in the middle of supplying two sets of rigging for a new-build International 8 metre that is to be campaigned on the European circuit.

This involved a fair bit of imaginative thought to incorporate the Dyneema into tip cup type spreader fittings and spreader root attachments for the discontinuous athwartships rigging.

This type of rig would not have been possible if we were constrained to using the bend radii and general largeness of Colligo/Precourt type of fittings.










Regards,

Joe Henderson, Henderson Rigging.

[alaskanviking]

Thank you for those pictures, very impressive. you reference bobbins however, ireally like the turnbuckles with the"bobbin"? at the top. while i suspect thier usefullness, i feel i am just shy of complete understanding. can you give a diagram of how one of those stays are put together? am i right in that these are "lashing bobbins"? and that they are used to connect to the tunbuckle to the end of the stay with a lashing but use the turnbuckle for tensioning? Do you have any pictures of one of these put together, or just the lashing portion? Please clarify.

[alaskanviking]

bobbin thimble, as in using the bobbin as a thimble, direct to the turnbuckle. i dont think i have ever seen an eye splice to a bobbin, do you have any pictures?

[Joe Henderson]

Dear Viking,

No, they are not "lashing Thimbles" and do a comletely different job.

Have a look at the pictures.

All those round things are what I (for want of a better name, and to distinguish them from round thimbles or lashing thimbles or bullseyes, or sheaves) have called bobbin thimbles.

I am certain someone on here will have a better name for them, such is the way of life!

You will also see some turnbuckle top ends with a thimble in the jaw end.

To terminate;-

Splice a loose eye around the thimble.

Apply correctly sized throat seizing in correct position to retain thimble.

Q.E.D.

Joe.

[rockfordwoods]

Joe, that is some fine looking and heavy rigging. It looks like it will be an incredible amount of fun to rig that schooner. I had considered making round thimbles as you have there, but thought that either 1) the throat seizing and whipping will have to be extra heavy to avoid the rope having an opportunity to jump out if the mast should whip a bit, or 2) you have to keep the clearance between fork, rope and thimble small enough so the rope cannot come out. Since you look to have taken the path of least clearance, are you able to put the throat seizings far enough from the thimble so they do not carry a heavy load from turning the line?

[Joe Henderson]

Dear Rock,

I have never seen a stay fitted with a bobbin thimble even come close to jumping out when the mast, inevitably, "whips a bit".

The seizing is in the same area that a normal seized - in thimble seizing is positioned, and ensures that the legs of the eye are no more open than with a normal heart shaped thimble.

Remember that bobbin thimbles are formed exactly the same as normal solid heart shaped thimbles ( which are sized and made to take a pin ) up to about 100 degrees each side of the crown and the line captures the bobbin in such a way that it is impossible to pry the thimble out of the eye.

Think of them as solid heart-shaped thimbles with 75 percent of the point cut off.

The clearances in the jaw and on the pin are snug, but not overly so, just the normal working clearance I would require for swaged or StaLok eyes on wire.

Clearance in the jaw, and in the upper tangs, has no effect on the security of the eye.

I have seen many seized-in, and both hand and machine spliced heart shaped thimbles that were slack up around the points with the thimble cocked-over in the eye, it would be difficult to pry those thimbles out of the eye too, but I have never seen one fall out in service.

You need a beefy rigging vise and the correct tools and materials to apply seizings that are reliable, long lasting and up to the task.

Regards,

Joe,.