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2:1 halyard hardware


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The equiplite stuff is nice but makes tylaska look cheap!

I think the friction ring and soft shackle is going to be the way for now, just gotta sort out how to tie the shackle

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29 minutes ago, Ed said:

The equiplite stuff is nice but makes tylaska look cheap!

I think the friction ring and soft shackle is going to be the way for now, just gotta sort out how to tie the shackle

Problem you need to consider with the soft shakle option Ed, is the tolerance you have above the headboard to the crane. I have know those who tie a bowline from a friction ring, down side is its never going to be a constant for luff tension.

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Thanks for putting that up IT. I've waded through that lot last night and this morning, Pity the diagrams are lost.  However  knowledgable the written points may be I still can't understand how mast compression is reduced although it seems those with  the experience say it is. Thanks again

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So i've done a couple of sketches and they show in a 1:1 setup with 50 kg (technically should be called 500 newtons) of force holding the sail in position there is 50 kg of "pull" in the halyard going from the sail going up to the sheave and of course the same 50kg pulling down inside the mast - so the sheave is compressing the mast by 100 kg.

With a 2:1 set up there is only 25kg of load on the halyard so 25 kg where it terminates above the sheave  plus the 25kg going from the sail up to the sheave as well as the 25kg coming down inside the mast giving a total of 75kg now... I'm pretty sure i've got this right , if needed i can get some help and  post my sketches. It looks to me that armchairs drinking buddies are onto it

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Thx Jim....I think I've just about got it now. It's the down ward force on the main luff that is the confusing point. But the anchor point for the halyard is at the mast crane. Then to a block on the main headboard so the load is 100 kg at masthead. So logically ( to my mind) the load at the mast step has to be 100 kg ? even if the load on the halyard is as you say? Thanks  again for explanation

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No, the compressive load on the rig is taken by the mast structure, between the mast top sheave, the tack fitting and the mast crane termination. If your halyard is fastened on the mast somewhere, then NO compressive load from the halyard is transmitted to the step. Think about this, if the rig is out of the boat,  and you fasten the halyard to a cleat on the mast, can you still tension the sail?? Of course you can, but there is no step!

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On freedom we had a low friction rig with a wide stainless steel shackle over it. It meant the pin of the shackle was very close to the top of the main and halyard. Simple and cheap!

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On 25/04/2020 at 11:51 AM, Clipper said:

Dont think thats right? 

Bit worried to have a go at this, but in the 1:1 case, the sail applies a 50kg load down, the halyard the same vaule to hold it up there, therefore masthead has 100kg of compression.

In the 2:1 case, the load required in the halyard becomes 25kg each side of the main, and another 25kg tension, so maybe 75kg compression?

Im ssure ScottiE or Ed will correct me if Im wrong.

Missed this sorry Clipper - yes you are correct - back yourself mate.  As well as lowering mast compression, it also halves the load needed for the halyad size - weight aloft.  Not so critical for halyard itself but good for those guuchi masthead halyard locks - ie. the load to release it is half!

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2 hours ago, Adrianp said:

On freedom we had a low friction rig with a wide stainless steel shackle over it. It meant the pin of the shackle was very close to the top of the main and halyard. Simple and cheap!

A home made version of this? https://marine.wichard.com/rubrique-Captive_pin-0201110100000000-ME.html

Any photo?

/Martin

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So I'm still thinking........ so many scenarios...Main halyard comes down  to block on mast collar then back to clutch aft. Say 50 kg.  So upwards lift on mast collar 50 kg ? Surely that transfers back up mast thence to mast step ?  Or am I overthinking / over complicating. BTW I wasn't good at Physics !

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There ya go, a nice work out for the grey matter to fill in some jail time.

I went to whip up a quick test rig last evening to show it all more graphically but the neighbour threw a bottle of gin at me and things went a little wobbly but we got this wee Hmmmm... thingy sorted.

Mast set up with cell in the middle.

no load.jpg

All loads zeroed out so any change is due to what we do.

1 no screen.jpg

Set up 1:1 with a 5.2kg weight added simulating a sail

1 2 to 1.jpg

The load showing with 1:1

1 2 screen.jpg

The set up changed to 2:1, same load

1 to 1.jpg

The load is now

1 1 screen.jpg

Checking the load

1 the weight.jpga

So changing from 1:1 to 2:1 saw the load change from 10.28kg down to 7.47kg which is around 25% reduction.

Lots of Bombay Sapphire East was harmed in the pissing around with that jig. With ginger ale, lime and lemongrass, pretty damn morish.

 

14 hours ago, Adrianp said:

On freedom we had a low friction rig with a wide stainless steel shackle over it. It meant the pin of the shackle was very close to the top of the main and halyard. Simple and cheap!

Concur, easy as, cheap as, do the same myself.

There are other fitting options equally as good, some would argue better, than the usual 2 or 3 go to's in NZ and all tend to be far better value for money.

1 no load.jpg

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This software is no where near as user friendly as the last version was. Excuse the randomness, it has a mind of it's own and can't be corrected.

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26 minutes ago, armchairadmiral said:

And thanks to you other contributors too. This has bugged me for years. This shutdown hasn't been entirely wasted.

It's a oldie but a goodie and it's worth coming up every now and again.

 

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