Unveiling Bullseye Strops for low friction rings

[Matt Johnson]

Originally Posted by Seaworthy Lass

I love this! Our fiddle blocks for our runners were stolen off our boat when we bought it. I replaced them with stacked Antal rings (20mm & 14mm) lashed like in Dockheads photos, but yours is a much better looking arrangement.

I haven't put the mast back up yet, and everything is in boxes, but when I do, I'll give this set-up a shot.

Matt

[Seaworthy Lass]

Originally Posted by funjohnson

I love this! Our fiddle blocks for our runners were stolen off our boat when we bought it. I replaced them with stacked Antal rings (20mm & 14mm) lashed like in Dockheads photos, but yours is a much better looking arrangement.

I haven't put the mast back up yet, and everything is in boxes, but when I do, I'll give this set-up a shot.

Matt

Oh, that's great! Not the theft, the fact you will find the arrangement useful.

The connection can be made a fraction shorter (I tested it, decided the loop needed another cm to force the second ring on, lengthened it, then found it was a cm too long ).
The connection can be made a bit longer and still be reasonably secure in terms of a ring flogging out.

To decide how big to make the loop I wound 6 mm dyneema around first and measured the length (this has about the same diameter as spliced 4mm).

Line diameter could of course be thinner for lots of applications. The probable 8000 kg breaking strain (therefore SWL of ???) with 4 mm would probably rarely be needed.

SWL

[Dockhead]

Originally Posted by Seaworthy Lass

I have been doodling thinking about what we should do with our new system for headsail sheet controls. Dockhead, thanks for the photo below. It us nice to have a base to start from.

A few comments:
The stacked rings on the sheet concern me with chafe issues. They could just be connected with soft shackles couldn't they?

The lower two rings could be connected to the pad eyes with soft shackles too.
They would work a fair bit better than loop strops. Using the same diameter Dyneema, soft shackles are significantly stronger than the loop strops if you use Evans's "Overhand/loop stopper" or a button stopper, both with buried legs. They are shorter than the loop strops as well, which may or may not be helpful.

The line to control the barberhauler could just be spliced to the ring, as you have done for the ring control line. If the line is too old to splice, then use a Diamond Short Strop, which opens therefore could be fed through the eye-spice already on the control line. This eliminates the long strop plus soft shackle combo.

No nasty kinking anywhere with cow hitches in the system then. Cow hitches are on par with a tight throat at the low friction ring in terms of stressing and weakening the system and I think need equal consideration.

I am not trying to criticize, just sharing what I would do, as it may help improve your system .

SWL

Note: I know that the two pad eyes distribute the load on the deck, but if you have one strong attachment point, you could put a Diamond Twin Ring Strop (as in the previous post) down there if you wanted/needed a 3:1 purchase on the twing (only one ring needed for 2:1).

I think these are all valid criticisms. I have my own thoughts about them:

1. The cow hitches do bother me -- you can see where the strop fibers are crushed. I guess a simple loop like with your shackle would help, but I think the ultimate solution would be much thicker bail on the padeyes. I think if the bail were 10mm or 12mm then this would be a completely different ball game.

And the padeyes need to be designed for really big loads, properly throughbolted with big backing plates, or welded on in case of a metal boat. I ripped one of my new ones right out, first time out . Although they were professionally done. They were not done right, and my crew from last year helped me do them better (10mm self tapping bolts through the aluminum plate under my bulwarks). So far so good.

The loads are huge -- don't forget the force multiplying effect of blocks. If you have simple single purchase, the load on the anchor is double the load from the sheet. Triple purchase like mine helps somewhat, but the anchor loads are still greater than the sheet load.


2. Inhauler. I don't think there's any issue of chafe at all, but it's unaesthetic to have the inhauler ring riding on the twing ring. One solution is to use the same ring for both, like this:



This is the Antal "Solid Ring" (solid rings-antal) which is intended to have all the lines put through the much larger hole, rather than around the circumference.

For triple purchase like mine this would require a lot of lines through that one hole -- messy. Perhaps double purchase would be enough, but see the comment about anchor loads.

[Seaworthy Lass]

Originally Posted by Dockhead

I think these are all valid criticisms. I have my own thoughts about them:

1. The cow hitches do bother me -- you can see where the strop fibers are crushed. I guess a simple loop like with your shackle would help, but I think the ultimate solution would be much thicker bail on the padeyes. I think if the bail were 10mm or 12mm then this would be a completely different ball game.

Yes, I know you are not ignoring the cow hitches. No one responded to your query regarding a better connection. Do you think just a conventional SS shackle with an 8mm (or thicker if needed) section would simply be the best solution for you? You are not concerned about weight.

Once you have exceeded the 1:1 attachment diameter:strop thickness requirement for dyneema, I think you would actually make it worse not better using a cow hitch if the pad eye was made thicker (to me the strop would be stressed even more badly).
That does help with soft shackle connection though.

Originally Posted by Dockhead

2. Inhauler. I don't think there's any issue of chafe at all, but it's unaesthetic to have the inhauler ring riding on the twing ring. One solution is to use the same ring for both, like this:

I saw that on the Pogo arrangement. It makes me uncomfortable having 3 bits going through the centre. I can just imagine a couple binding at the worst possible time. I would split them as you did .

I would much prefer not to stack them though. This is what I meant connecting two with a soft shackle:







Just throwing around ideas .

SWL

[Dockhead]

Originally Posted by Seaworthy Lass

Yes, I know you are not ignoring the cow hitches. No one responded to your query regarding a better connection. Do you think just a conventional SS shackle with an 8mm (or thicker if needed) section would simply be the best solution for you? You are not concerned about weight.

Once you have exceeded the 1:1 attachment diameter:strop thickness requirement for dyneema, I think you would actually make it worse not better using a cow hitch if the pad eye was made thicker (to me the strop would be stressed even more badly).
That does help with soft shackle connection though.




I saw that on the Pogo arrangement. It makes me uncomfortable having 3 bits going through the centre. I can just imagine a couple binding at the worst possible time. I would split them as you did .

I would much prefer not to stack them though. This is what I meant connecting two with a soft shackle:







Just throwing around ideas .

SWL

Your first variant puts all the twing force in a single shackle looped through the ring. This is not good with the hollow ones -- they are designed for the main part of the force to transfer from a line around the circumference and are much less rated for loads applied at either edge. You'd need a "solid ring" for that kind of duty, but then you lose the line around the circumference.

Simplest of all would be just to throw a soft shackle through the existing twing ring and shackle to the end of the inhauler line (which has a spliced eye). Or a single loop of dyneema spliced through it. Should not create any chafe problems even though that's three lines going through the ring -- they will bear on different parts of the ring (sheet -- top; twing -- bottom; inhauler -- side). The inhauler produces much less force than the twing so should be ok to load the ring like that with it.

Maybe I'll try that.


And I want that Antal hook. That will be just the thing for barber hauling the staysail, or any other barber hauler. No need to re-reeve anything.

[Seaworthy Lass]

Originally Posted by Dockhead

Simplest of all would be just to throw a soft shackle through the existing twing ring and shackle to the end of the inhauler line (which has a spliced eye). Or a single loop of dyneema spliced through it. Should not create any chafe problems even though that's three lines going through the ring -- they will bear on different parts of the ring (sheet -- top; twing -- bottom; inhauler -- side).

Yes, that is simplest .
I just don't really like using 3 things going through. With flogging, jamming may occur. It may also start to get a bit tight in there? Max ring size I have found is 28 mm ID. What size is yours? Three would work better on a smaller boat with thinner lines with a 28 mm ring.

[Dockhead]

Originally Posted by Seaworthy Lass

Yes, that is simplest .
I just don't really like using 3 things going through. With flogging, jamming may occur. It may also start to get a bit tight in there? Max ring size I have found is 28 mm ID. What size is yours? Three would work better on a smaller boat with thinner lines with a 28 mm ring.

I really don't think jamming is a big risk. How could they jam? I think it would be ok. My rings are 28mm, sheet 14mm (recently downsized from 16mm), control line 10mm, and plenty of room in their for a single strand of slippery 6mm dyneema.

Another way to do it might be to get a loop of dyneema around the circumference.

[Seaworthy Lass]

Originally Posted by Dockhead

Your first variant puts all the twing force in a single shackle looped through the ring. This is not good with the hollow ones -- they are designed for the main part of the force to transfer from a line around the circumference and are much less rated for loads applied at either edge. You'd need a "solid ring" for that kind of duty, but then you lose the line around the circumference.

Yes, it does too. I had forgotten about the weaker rim of the ring.
I do not think it would be an issue on the bottom soft shackles (load would not be on the rim?), but it would if the twin rings and one attachment point was used. So scrap that idea.

[Alan Mighty]

Originally Posted by Dockhead

And I want that Antal hook. That will be just the thing for barber hauling the staysail, or any other barber hauler. No need to re-reeve anything.

Me too!


I could use a couple three 12 mm Antal hooks. Best price I've found so far is USD 84 (defender.com); comparable prices include GBP 75 (thechandler.co.uk). Any better sources??

[Seaworthy Lass]

Originally Posted by Dockhead

I really don't think jamming is a big risk. How could they jam? I think it would be ok. My rings are 28mm, sheet 14mm (recently downsized from 16mm), control line 10mm, and plenty of room in their for a single strand of slippery 6mm dyneema.

Another way to do it might be to get a loop of dyneema around the circumference.

Circumference is being used for the 3:1 purchase.

Hmmm. Are you sure you have enough room? 24 mm of the 28 diameter is taken up with your headsail sheet and twing line. I know they will squish, but still...
The soft shackle going through would have two loops of 6mm dyneema not one, so it sounds really tight to me.

The jamming issue is if load is taken off two with panting (your sails would not flog ) and the load was put back on one before the other, maybe it could jam on top of the yet unloaded one? Maybe it is not an issue if you are filling the ring completely? No idea, but I just don't like it.

[Seaworthy Lass]

Originally Posted by Alan Mighty

Me too!

I could use a couple three 12 mm Antal hooks. Best price I've found so far is USD 84 (defender.com); comparable prices include GBP 75 (thechandler.co.uk). Any better sources??

We are using a Wichard simpler, mini version of this:

[Dockhead]

Originally Posted by Seaworthy Lass

Circumference is being used for the 3:1 purchase.

Hmmm. Are you sure you have enough room? 24 mm of the 28 diameter is taken up with your headsail sheet and twing line. I know they will squish, but still...
The soft shackle going through would have two loops of 6mm dyneema not one, so it sounds really tight to me.

The jamming issue is if load is taken off two with panting (your sails would not flog ) and the load was put back on one before the other, maybe it could jam on top of the yet unloaded one? Maybe it is not an issue if you are filling the ring completely? No idea, but I just don't like it.

The diameters aren't additive. There's lots of area inside the ring.




Here it is with two strands of 8mm dyneema, 14mm sheet, 10mm control line.

I would splice a loop of 6mm so it would be a single strand, and there will be more room in the ring than there was when I had a 16mm sheet plus 10mm control line. I did several thousand miles with that combo and not a trace of chafe.

[Seaworthy Lass]

I am just mulling on the rim issue.

If you have reasonably high loads how do 3 control lines work without stressing the rim of the ring? To me it seems this would only work if the forces from all 3 control lines were in the one plane. That definitely is not occuring with a system like yours.
Even stacking the rings, as you have done, it appears the rims of the two rings would be pushed together at the outboard point? Is it less of an issue as the load on the outhauler is not huge?

Why would it be any worse having two rings connected with a soft shackle?

SWL

[Matt Johnson]

Originally Posted by Seaworthy Lass

We are using a Wichard simpler, mini version of this:

Unfortunately, I haven't found anybody in the US selling those.

[Seaworthy Lass]

Originally Posted by funjohnson

Unfortunately, I haven't found anybody in the US selling those.

They are a French company. We bought ours while in Australia, so they must be available in the US (we tend to lag behind down under ).

I just had a look and found the US branch. They would have a list of distributors. You can also by online here:
http://www.wichardamerica.com

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3901 Pine Grove Circle
Charlotte NC 28206 - USA
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