Which Knot

[boatman61]

Originally Posted by tager

Eye splices, thimbles, shackles.

Just hope your a fast splicer.... in an emergency...

[Viking Sailor]

Ah, did I read the OP's post wrong? It reads as if he is wanting to know how to attach 10 mm chain to 18 mm line to extend his all chain rode.

In an emergency I would put as large a shackle as would fit to the chain and tie a double looped bowline in the line.

The correct way is of course to splice a thimble to the line and shackle the chain and line together.

[daddle]

The two bowline is not too bad of an idea. But a practice that runs throughout knot technique is that the loaded bight in the knot, or connection, loops around at least two pieces of the line. This prevents sharp bends. The small diameter of bend where the two bowline loops connect will probably weaken the connection unnecessarily.

The other knots are good. I use the doubled figure eight to join lines that must never come apart no matter the conditions. I can't ever remember how to tie the even better Carrick Bend

Just a tip.

[savoir]

If the two ropes are of uneven size a double sheet bend works well and will not undo itself.





Don't ask me why, just click on it. sav

[Hydra]

Originally Posted by Ziggy

For joining two ropes I always use the double fisherman bend. It is very compact and secure.

IME, the double fisherman bend is so secure that it is often impossible to undo after having been put under tension. It is often necessary to cut the ropes.

In a hurry, I prefer the double sheet bend. With slightly more time, I upgrade to a carrick bend.

Alain

[Capitain Mike]

Fig8s I presume you mean stop knots

[Capitain Mike]

Every time you loop the rope it is made weaker.
Use a rope thimble and a bowline hitch with the end whipped.
look here available on iboats

http://www.iboats.com/Seasense_Rope_...-view_id.56497

[Ziggy]

Originally Posted by Hydra

IME, the double fisherman bend is so secure that it is often impossible to undo after having been put under tension. It is often necessary to cut the ropes.

I've heard that said, but in my experience it isn't true. I was always able to untie a double fisherman, even after it was subjected to large loads. Sometimes a marlinspike comes in handy with knots in small diameter rope (not recommended for anchor line), but I have never had to resort to a knife.

[Kettlewell]

Does anybody know of any information on how strong it is if you just loop two eye splices together? It forms what looks like a square knot in the middle. It is hard to imagine that it wouldn't be stronger and more secure than any possible knot, but maybe I'm wrong. I can't remember where, but it seems to me that one of the offshore gurus or maybe sea anchor companies recommends this as the best way to attach one long rode to another.

[klem]

Kettlewell,

The information that you are looking for was covered in a study by MIT on mooring pendant failure. If you google it, you should be able to find it. Basically, they found that it was a very good way to connect two lines and that most failures they produced through testing occurred outside of the connection point. Their recommendation was to actually use a poly pendant over any chafe points then use the method you describe to attach it to a nylon pendant to go to the chain.

[GMac]

Originally Posted by Kettlewell

Does anybody know of any information on how strong it is if you just loop two eye splices together? It forms what looks like a square knot in the middle. It is hard to imagine that it wouldn't be stronger and more secure than any possible knot, but maybe I'm wrong. I can't remember where, but it seems to me that one of the offshore gurus or maybe sea anchor companies recommends this as the best way to attach one long rode to another.

If the splices are good the most likely failure point will be from rope on rope chafe. Under load there could be a fibre on fibre friction issue, how big depends on the rope material.

And as you are making pretty much a permanent join in 2 ropes why not just splice the 2 directly together, it will be stronger and safer long term. Probably quicker to do as well.

[Kettlewell]

Gmac, the OP was asking about how to join additional line to your anchor rode if you need a longer rode for a storm, etc. The idea of having just loops in the end so you can put them together has been mentioned in several places, and was recommended in an MIT study referenced here. Apparently they think it is strong enough for a hurricane mooring system. I have done this with lines under a lot less stress than that, and there appears to be very little movement, if any, in the joint, once it's tightened up. I've also read of several places that put in permanent moorings that recommend just looping the line through the swivel or the shackle, without any thimble, as being stronger and less prone to failure. It does seem that this provides double the bearing surface for the line and spreads the load out pretty evenly over two full pieces of line--the two legs of the eye, plus there is no worry about securing shackle pins or the breaking strain of the shackle or the thimble. It would be interesting to have one of these joints tested for breaking strain.

[SaucySailoress]

Originally Posted by ozskipper

knots Thats my 2c

Very nice link, thanks

[Kettlewell]

I forgot to say that the MIT study referenced above did test the eye to eye join between a polyester and a nylon pendant. But, what I would like to see is how strong this join is between two similar lines, and compared to other rope connector possibilities like some of the knots in this thread, or two thimbled eyes with a big shackle. I'd also like to see a test of how strong an eye just looped through a shackle and back on itself is compared to having an eyesplice around a thimble. I can't see how it could be any weaker than the crown knot-type splice that people do between three-strand and chain, and everyone seems to trust.

[smurphny]

I'm in the eye splice camp. Carry three extra 200' anchor lines with thimbles and eyes. They are easily joined by shackles when needed and work as lines for sea anchor as well as for any time a longer anchor line is needed. The eyes are a PITA sometimes because you have no free bitter end but worrying about knots failing is not an issue.