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Bend knot through eye splices strength ?

3K views 11 replies 4 participants last post by  lillia28 
#1 ·
Hey,
I am looking to find some information about the strength of tying to lines together - this is for a mooring application - .

I have eye splices at each side, and I am tying one line into the eye of the other one by going with the loose end through the eye, like this :



I cannot find the name of this technique and I am wondering if this is strong enough, i.e. the actual working load of the line itself.

Any help appreciated. Even the name of this "technic" would help.
 
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#2 ·
It really depends on what the line is. Assuming you are working with dyneema...

The technique... I don't think it has a name. But it is a deconstructed soft shackle. The other end of the line should have a sliding eye spliced into it that loops over the knot. When it's pulled tight the eye closes around the knot.

The standing portion there looks like a standard diamond knot, and will have a breaking strength equal to the line strength. There is a better knot that has a proven breaking strength of twice the line strength.
 
#3 ·
Cow hitch, larks head, strap hitch or girth hitch (sometimes also called a luggage tag). I think it's a fairly weak knot in terms of line strength, and also a bit of a swine to undo if it has had a lot of tension. You could instead feed the end of each line through the eye of the other.
 
#4 ·
Thanks, I was able to google it, and yes, it looks weak - although I don't really get why - maybe the directions of the forces...

Anyway, I am using that to create a 'V' between my 2 Bow clew and the mooring pickup line, using 2 lines, like a Cata.

"You could instead feed the end of each line through the eye of the other." - do you mind to explain better ?

I was worried that just going from on side to another, using only one line, from Port to Starboard, through the eye, will create some shaffing (with the pendant line sliding through the eye of the mooring pickup line).
Now, If I somehow setup anti-shaffing in the eye, I realize this will end up to be a stronger setup, certainly egal to line strength ?


I am using 3 strand Nylons and Blue Steel , 1" & 1.25" respectively each.
 
#5 ·
"You could instead feed the end of each line through the eye of the other."

I just got what you meant.
It is not super practical as one end of the line goes in the mooring shackle but it could be useful for storm preparation.
Is it stronger ?
I am considering eye splicing through each other eyes. it is kinda definitive, but I like the idea of the strength of the blue steel and stretch of the nylon together.
 
#6 ·
It is considered a weak knot because the diamond here will break at 50% of the theoretical strength. But note that the theoretical strength is 2x the line strength since the line is doubled up. If you are using 1.25" amsteel blue that means the knot will break at around 165,000lbs. You can switch to a modified button knot developed by Estar, Brion toss, and Allen from L-36.com that has been tested to 2x line strength, in this case 320,000lbs. Here are the instructions on tying it. How to Tie A Button Knot

But I would suggest that if you are dealing with a mooring system expecting these loads that you need to contact a mooring engineer not a sailing forum. These loads are high enough to result in loss of life if not dealt with properly.
 
#9 ·
I have seen that before.

I have a setup with the hardware on the top of the buoy and 2x 15' pendant lines, and 15' pickup line, all three spliced.

I had a bad surprise when the boat was riding on the buoy , maybe aft-mid ship, and the hardware badly damage the paint and the gelcoat. I think the wind and currents were opposite and the bow got stuck between the V of the 2 pendant line for a while. It was weird, the boat was going straight forward, with the buoy straight backward, Facing the current and pushed by the wind.

I am thinking by adding another 20' of line to the pickup line, at least, if the boat rides the buoy, it would clear it aft.
I am thinking about shortening the V-pendant to few feets, and use this new 20' "extension" to get the needed strech.

The mooring itself is rock-solid and has been "engineered" properly.

I am considering moving the hardware under the buoy itself and keep the buoy attach with a nylon line, then if it rubs the hull, it will be nicer on the boat.

I guess my question is : what is the best way to attach the pendant lines to the pickup line, for my V Clews, considering all this.


ps: and yes, I am running out of time as we have a tropical storm headed our way, -Hawaii - , in a few days. Nice :(
The boat is 37'.
 
#12 ·
A couple of questions,
Is the mooring ball one that allows the chain to pass through, or one with a eye one each end connected by a steel rod?
If the rod type, it is best to attach one pendant directly to the chain, below the ball. A shackle a foot or so below the ball will prevent chaff.
Why are you using 2 pendants? If for security and back-up, why interconnect them? Interconnected, a single point failure will set the boat adrift. Best security is two compeletely independant lines, the back up line 2or 3 feet longer than the primary line. Imho, the easiest set up is to leave the eye splice on the boat, and attach the bitter end using a anchor bend. or anothe eye splice protected by a thimble and a shackle. On a mono hull there is little benefit to a vee. I know the picture was an example, but I would NOT use a welded ring for any reason on a mooring. Pool noodles will float the lines and prevent wrapping around the chain. If you want to avoid the pendants wrapping around each other, lace them as shown in Maine's link.Pools noodles, in addition to being cheap, also deter theives. They are so tacky no one will guess there is anything valuable on the boat. I'VE used them for years and my boat has never been robbed!
 
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