Intriguing mind bender - mainsail tack shackle.

Refueler

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This defies logic ...

Picture a mainsail with bolt-rope to boom and mast track slugs. It has a standard eye in the tack of the sail...

The gooseneck end of boom has an eye bolt that lays in line with boom .. that is the 'hole' is 90 deg to the boom.

This is not first time I have tried to use a standard D shackle ... the tack eye and boom eye are same orientation ... but when sail is hoisted - the shackle twists and it does not work. It needs a 'twisted D shackle' that is a shackle that twists through 90 deg ...

Go on you Einsteins work that one out !!

I have tried ordering twisted shackles - but the sizes are all to cack ! bid enough - but 'jaw size' is limited. usually I e4nd up using two shackles combined to do the 90- deg ... but I am thnking this time to remove the shackles and lash it with light line ... with enough line free - to let me use to the reef cringle ... solving two matters in one.
 
Quote ..."but I am thnking this time to remove the shackles and lash it with light line "...
I like that idea, using cheap "software" instead of expensive hardware
 

The problem is I can find plenty exactly same at 10mm pin etc - but that is the problem ... the diameter is 10mm bar and makes the 'throat' too small to pass over the sail / eye of the sail ....... length is perfect at 50mm .... but its the 'throat' size.

Your link is what is classed a 12mm twisted shackle.
 
[...][

Picture a mainsail with bolt-rope to boom and mast track slugs. It has a standard eye in the tack of the sail...

The gooseneck end of boom has an eye bolt that lays in line with boom .. that is the 'hole' is 90 deg to the boom.

[...]
Do you mean like this?

1754416493789.png
 
Maybe it had a small block attached to it, which would orientate the rope correctly (whether for not there were a similar block attached to the sail).

I had such an arrangement on a previous boat, with a pair of tiny blocks, and the stainless body of the block at the boom end had a V jammer cleat formed in it.

This one is a Seaure 'Single 25mm block with V Jammer Cleat', but numerous variations on this theme available from various suppliers.

1754417598673.png
 
The problem is I can find plenty exactly same at 10mm pin etc - but that is the problem ... the diameter is 10mm bar and makes the 'throat' too small to pass over the sail / eye of the sail ....... length is perfect at 50mm .... but its the 'throat' size.

Your link is what is classed a 12mm twisted shackle.
Are you absolutely sure that the bolt cannot be turned so that a regular shackle can be used?

I have a similar system, and sometimes when putting the main on we need to get a long screwdriver into the hole to give the leverage to turn the bolt and line the hole up correctly so we can fit the shackle.
 
Looks like the perfect place for a bit of string to me, can't see any advantage to using hardware given that if you used line, you could get the length / tension exactly how you wanted it.
 
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