HM Attachments

[Jack]

Jake,

Those loops are made by New England I think, I talked to the head of the company about them. They sell to Harken and others. It is Dyneema SK-75 spliced in a loop/hoop like Brion shows in his book 5. They have a nice looking cover over it. Harken as well as many others are going to looped blocks. It all came out of the big round world race boats who were lashing blocks vs. shackles.
I just up loaded a bunch of photos to my URL and one shows the use of a softie on a boom block on the Westsail.......we renamed it the "Wireless Westsail"...check it out.

[davidsamuelson]

Hi,

To answer Dan's question of why I decided to make a hardware-free snap shackle, the answer, as is nearly always the case: necessity is the Mother of invention

I am currently 7° from the equator and that means no, or very light wind. My genoa is a normal cruising sail: stainless ring at the clew plus many extra layers of cloth to beef it up; in a word, heavy. Add to that 2 polyester lines with knots and sometimes some water and the weight is too much for the sail to have any shape.
Then a racing friend of mine was talking of removing his masthead tricolour light, plus wiring, to have less weight aloft. I suggested getting rid of his halyard snap shackle since that probably weighed more than the light. Hence the soft snap shackle.

Your criticism of my soft snap shackle Dan - well noted. ( He says "The tight bend on the standing part spells weakness") This bend is probably no tighter than the bend it makes at the clew of the sail so now I have 2 weak spots instead of just one; does this make it less strong?

How much strength is lost if a 5mm line is bent around itself?

Thanks, David

[Jack]

David, Removing running lights is radical surgury...... I had a Catamaran sailor tell me he uses a whip antennae on deck for his VHF because he figured the weight on the co-ax cable up the mast was no good.....:-)

I think the light air, or no air sailing is where I notice my lighter rig the most. After losing 40 lbs. off up high, the boat was much less prone to hobbyhorse, or jig back and forth on the swells/chop without the wind to hold the boat steady. It settles in quick and moves fwd. without shaking the little bit of wind out of the sails.

I had another guy tell me he spliced an eye in his sheets, and used a soft shackle to attach the headsail. It was lighter, and came across the for inside stays much better.

I use the soft shackle for tacks, headsail and mainsail attachments, and will be attaching the sheets soon.....:-)

[Dan Lehman]

Originally Posted by davidsamuelson

...
Add to that 2 polyester lines with knots and sometimes some water and the weight is too much for the sail to have any shape.
...
Your criticism of my soft snap shackle Dan - well noted. ( He says "The tight bend on the standing part spells weakness") This bend is probably no tighter than the bend it makes at the clew of the sail so now I have 2 weak spots instead of just one; does this make it less strong?
How much strength is lost if a 5mm line is bent around itself?
Thanks, David

I see that my thinking is going awkwardly between materials, here: the SK-75
in Jack's case, but PES in yours -- which makes a big difference in the effect
of sharp bends. But, in any case, I could even see some risk of your S.Part-tucked=
through-end structure leading on heavy loading to deformation of the end's split
around the S.Part, pulled wide out around itself, a loop/circle transforming into
a spiral, esp. on the side opposite the stopper. But even with PES (polyester),
I'm guessing 50% or so is lost, maybe more.
As for comparing with the hard turn around the clew, consider that the tension
on the eye legs should be half that in the S.Part, so even at equal *hurt* per
load, the load is halved, there. But metal typically is kinder to the fibres than
they are to themselves, re friction.

In composing the reply here, I'm also led to think of connecting soft eyes via
a soft shackle that is made of a double (even tripled) loop of material, the
ends just stoppered on opposite sides of the clew? -- doing so offloads much
force from these knots, which themselves stay oriented AT the clew and so
free of the connected eyes, and the bulk of the two (three) runs of material
give some extra bulk for the eyes to load and combined resistance to chafe?
-- of will this be a chafe situation only somewhat ameliorated, still bad enough
to discount?

But let me try to quickly put images to my earlier musing about a sort of
brummeling of an eye bight back through the brummels of a splice,
with the UNburied long tail used to toggle in place the eye tip, for easy
attachment/detachment to a clew. NB: what I present is done for a quick
proof (presentation) of concept; there might be a better implementation of
the idea, esp. re the brummel, where the "Mobius" one of having tucks
of both end & S.Part once will make for a better mechanism -- for now,
it's easy for me to just tuck the end both places, put in a Half-hitch on
redirecting the end back to make a single-strand toggle (I envision a
2nd pass but haven't the material at hand in this play rope).

The first image is slightly exploded to show the structure. Perhaps
there should be two tucks of the eye (hence, a 3rd brummel tuck) ?





--dl*
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