Dyneema rigging

Back at stretching dyneema rigging

Dave Warnock

Dave Warnock

— 3 min read
Back at stretching dyneema rigging

Jane has finished the first 8 chainplate loops in 12mm dyneema for the main mast (we don't need one for the forestay and the inner forestay will be different).

Plus she has finished 3.5 of the 4 lower shrouds (also 12mm dyneema).

So we are back to stretching them in the garden.

This meant I needed to finish the Acetal thimbles that I've been making. They are much larger diameter than the low friction rings, much cheaper than larger low friction rings and by routing each turn of the lashing through a separate hole should be lower friction with reduced binding.

Using the router to cut grooves into the Acetal. I need to get better at spacing them. 9 grooves but one of them didn't have enough width to cut, so I got 8 from this section.
8 thimbles ready for the chainplate loops (I need 8 more for the bottom of the shrouds)
I've gone for 5 holes in each, so 10 lengths of 5mm dyneema for the lashing.
Testing the first Acetal thimble to 2,500kg it shows no wear at all

We don't really trust our homemade stretching rig beyond 2,500kg so we may still have some stretch for the first year.

Nearly the full length of the garden diagonal
The pull along has a capacity of 1,500kg, now using 6mm dyneema in it
The scale needs a cardboard sun hat or we can't read it. The chainplate loop knot is far left (that will be under the deck)

So far we have stretched the first lower shroud and first chainplate loop. Went very smoothly. The acetal thimble is working beautifully, it shows no wear and nor does the lashing line.

Just for reference the chainplate loop should be good for over 30,000kg, the lashing should be good for 26,000kg, and the shroud for 18,000kg. Definitely over specified (but remember the sizing is for stretch not strength).

Now that I've taken off the first chainplate loop and lower shroud it's easy to see how beautifully the knot and splices have tightened up. The knot sounds just like a hammer if you knock it against something and the splices in the shroud really don't want to bend.

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