Emergency anchor line extension

[StuM]

Originally Posted by estarzinger

^^ I have tested them extensively and yes the Zep is stronger and slips less.

I think the zep is easier to tie 'wrong' than the sheet bend . . . but if you tie the zep enough that problem goes away.

BUT . . . typical knot strength testing is done with a slow 'static' pull, which is unlike the OP's case - where the knot is more likely to be damaged by heat effect than just pure pull loading.

If you look at the previous long Zep thread, SWL has photos of one that she used for days on an anchor warp in heavy winds. It is well worth looking at.

[StuM]

Originally Posted by Cheechako

I was wondering the same thing, but his parameters said "the end is whipped". I assumed he didn't want a splice. But yeah, a simple splice doesn't take long if you are not picky.

I refer back to the OP's hypothetical:

"You decide to knot the two lines together. Which knot and why? "

Whether or not that is the correct decision in the circumstances is a different topic.

[Hydra]

Just to add a little difference of opinion here, but I think I would use a double fisherman's knot. Although it can be harder to untie when heavily loaded I believe it is ultimately among the strongest of knots along with the double figure 8 for joining ropes.

I wouldn't use a double fisherman knot, because it can't be undone without a knife after being submitted to some traction. This is the precise reason why climbers use it.

Alain

[estarzinger]

Originally Posted by StuM

If you look at the previous long Zep thread, SWL has photos of one that she used for days on an anchor warp in heavy winds. It is well worth looking at.

Yea, I just looked it up . . . the net was that it was easy to untie. Which IMHO is not a very important criteria in the OP's situation. Yea, it would be nice, but nowhere near the top of the list.

What SL did NOT do is break the knot, and several others in those conditions. That would have been interesting, because I am not aware of much testing done to breaking limit in heavy cyclic loading with nylon. And I expect the results could be quite different than in the sort of static testing which I have done.

I remember when we discovered that long double braid nylon para-anchor rodes would internally heat up in this sort of cyclic loading and could then break at half their rated strength. That was a surprise to many. I also was initially a bit surprised with I did a drop test (dynamic shock load) and 1/4" nylon held while 1/4" dyneema broke - despite the dyneema having a much higher breaking load than the nylon (it was obvious after I did the shock load math but was not what I expected). That is the sort of effect I am wondering about here in this specific application.

I am not at all saying anything bad about the zeppelin. It tests and performs very well in static situations, and I would not be surprised if it did well in tests simulating this situation. . . . It is just that I do not have any data or experience to suggest whether it is better than alternatives in this specific situation. One thing I learned from my testing was that yes there were surprises when you actually did controlled repeatable tests. Conventional wisdom was wrong in a number of cases. And dynamic loads and cyclic loads did produce different sorts of results than one might have originally expected.

[Paul Elliott]

Originally Posted by estarzinger

typical knot strength testing is done with a slow 'static' pull, which is unlike the OP's case - where the knot is more likely to be damaged by heat effect than just pure pull loading.

In this case, presumably the splice will be under water at least most of the time. Do you think heating will still be an issue in a submerged splice?

[estarzinger]

Originally Posted by Paul Elliott

In this case, presumably the splice will be under water at least most of the time. Do you think heating will still be an issue in a submerged splice?

We know that heating is an issue in submerged nylon double braid para-anchor rode. So, all I am saying is that there certainly is a good chance it is here.

[Terra Nova]

Originally Posted by PuppyFeet2

...Seafarer 26...anchor in 20-30 feet of water with a bottom just made to hold your anchor. You have 200' of 1/2 3-ply nylon with a boats length of chain connected to the anchor. Anchored at better than 7:1.

Storm comes up with advanced warning and rather than leave the relative safety of your anchorage you decide to extend your anchor line using another length of 1/2 3-ply nylon line...

You would have done better if you had, instead, doubled the length of your 26' chain.

[Lizzy Belle]

hypothetical

adjective
1. based on or serving as a hypothesis.

noun
1. a hypothetical proposition or statement.

(Just as a reminder for all the posts discussing the situation and what's wrong with it )

[PuppyFeet2]

First off, thanks for all of the replies, interesting reading, especially regarding the zeppelin knot. I'd never heard of that one but it seems like it should be added to my stock of basic knots!

For those of you who "got" the core of the question, all i was looking for were suggestions for joining two lines together in an anchor rode situation in an emergency. Yes, more chain than a boats length would be nice but i don't carry it being an occasional weekend overnighter. Yes, perhaps splicing would be better but i don't see myself splicing on deck under "emergrncy" circumstances.

Yes the boat is 26' and gross weight is about 5700lbs so 1/2 inch 3ply is quite adequate. Yes i do have 200' of rode with a couple of other lengths of 3ply and wondered if lengthing the rode in an "emergency" situation would benefit. To do that i specifically asked regarding knots and the Zeppelin seems to fit.

I'm certainly not advocating knoting an all line rode nor am i saying that i would be anchoring out in any kind of 50-75k winds. I am saying that if i happened (very remote likelyhood!) to find myself in that type of situation, i would want to lengthen my rode as much as possible and to do that i would likely (now) use a Zeppelin knot to do so.

Thanks again all for your comments and suggestions!

John

[Training Wheels]

Why not just splice an eye in the bitter end of your rode now? Then if necessary you can just shackle your rides together.

[estarzinger]

^^ +1

All my "spare rodes" had thimbles spliced in one end, so they could actually be shackled to anchors when needed.

[usrowboy]

Zeppelin Bend | How to tie the Zeppelin Bend | Climbing Knots

animated knots!

[estarzinger]

The one thing that has given me pause about the zep is . . . It is not a new knot, and yet it is not used very much, and not on the "short list" in any serious activity (such as commercial heavy lifting or mountain climbing). I have always wondered why, what negative is there which stops people adapting it?

The cordage/knot using community usually adapts pretty quickly. Picked up soft shackles and related as they were developed. Climbing switched from bow lines to 8's when going to nylon line. Fishing has adapted server all times to developments. Typically the best performing knot is pretty quickly adapted. So I don't think it is resistance to change.

So here we have a knot that's been around for 100 years and still not much used.

Is it too easy to tie incorrectly? Or are the tails sticking out at 90 degrees snag hazards? Or . . . Why is it not used or taught much in any activity that takes it ropes seriously?

[Paul Elliott]

Originally Posted by estarzinger

The one thing that has given me pause about the zep is . . . It is not a new knot, and yet it is not used very much [...]

Excellent question and observations. The zep is pretty bulky, and as you note the tails stick out at 90 degrees, so perhaps that's it?

[Palarran]

Originally Posted by PuppyFeet2

Hypothetical situation . . .

At anchor using a new style anchor in 20-30 feet of water with a bottom just made to hold your anchor. You have 200' of 1/2 3-ply nylon with a boats length of chain connected to the anchor. Anchored at better than 7:1.

Storm comes up with advanced warning and rather than leave the relative safety of your anchorage you decide to extend your anchor line using another length of 1/2 3-ply nylon line. The bitter end of the "in use" anchor line is whipped as are both ends of the "spare" 3-ply line.

How do you choose to join the two lines? You have some time but not a lot and there are other things that need your attention. You decide to knot the two lines together. Which knot and why?

Personally, I think you would be making a mistake trying to add length to your rode when your already at 7:1. The extra scope won't change the pull angle significantly but the extra length will allow the boat to surge substantially more. If your just asking the hypothetical question of get an answer on how to join two ropes - carry on.