Mooring line release knot

[Ewan123]

This is probably more thought experiment than something of use, but here goes.

 

I wondered whether anyone uses/ can recommend a knot that could be tied midway along a mooring line, such that a quick pull on the knot would release extra length in the line (to be used in case of swiftly dropping water levels, for example).

 

As I type this,  I know the best approach is probably either "moor somewhere less risky" or "keep an eye on levels and adjust line length as required", but it's fun to think about.

 

Any such knot would need to not go solid with the repeated tensioning as the boat moves around, and be deliberately releasable while under significant tension.

 

🤔

 

I write this as I watch us slowly descend in a relatively short pound and remember a night back in London, waking up to find the boat on a Big Tilt after someone left paddles open.

 

Edited June 27, 2023 by Ewan123

[Sea Dog]

Around a dolly, just use the simple hitch known as the canalman's hitch.

If it's a T stud, look up what yacties use.

Both are simple to do, thoroughly reliable, and easy to release even under tension. Just make sure you coil the free end of the line neatly rather than wrap it round things or "use it up" by more knots or hitches.

No need for anything "midway along a mooring line".

Google will find you tutorials for both.

[Ewan123]

8 minutes ago, Sea Dog said:

Around a dolly, just use the simple hitch known as the canalman's hitch.

If it's a T stud, look up what yacties use.

Both are simple to do, thoroughly reliable, and easy to release even under tension. Just make sure you coil the free end of the line neatly rather than wrap it round things or "use it up" by more knots or hitches.

No need for anything "midway along a mooring line".

Google will find you tutorials for both.

Done and done, I just use a figure 8 on our T-stud, free end left loosely coiled.  Oh well, I'll stop trying to overcomplicate things. I do like playing with knots though so might just have a go.

[Tonka]

7 minutes ago, Ewan123 said:

Done and done, I just use a figure 8 on our T-stud, free end left loosely coiled.  Oh well, I'll stop trying to overcomplicate things. I do like playing with knots though so might just have a go.

a sheep shank in the rope

[LadyG]

I don't think there is such a knot as OP wants which is foolproof, I can imagine some bodge involving loops and sticks, (I'm thinking Bandboy) but any knot in a rope introduces weakness. Under tension knots tighten up, that's how it works. The reef knot can usually be undone, but it's only because it is used for reefing type situations.

Thinking back to salty days: tied up to a nasty big pier in the sea(Campbeltown 1977), we suspended weights on the bow and stern mooring lines so there was always tension on the lines, regardless of state of tide .

The Ashley Book of Knots has lots of knots, as the title indicates.

 

Edited June 27, 2023 by LadyG

[Tam & Di]

The problem with a sheepshank is it is not easy to release when under tension. The lorry drivers' knot which involves double purchase for tying down his load is vaguely related to this, but I can't imagine using it for the purpose suggested by the OP.

 

Tam

[Ewan123]

35 minutes ago, Tonka said:

a sheep shank in the rope

That's sort of the idea I was thinking of, though apparently that one can come loose under too little or too great a load 😕 

I'm also thinking it's unrealistic as I prefer to double up my lines, having effectively 4 lines between each point.

Edited June 27, 2023 by Ewan123

[Tam & Di]

If you are interested in knots you might like to look at this on my barge handling site: http://www.bargehandling.com/Bargehandling.com/BARGE_HANDLING_BLOG/Entries/2016/11/8_Knots_and_whatnot.html

 

Tam

 

[Ewan123]

57 minutes ago, Tam & Di said:

If you are interested in knots you might like to look at this on my barge handling site: http://www.bargehandling.com/Bargehandling.com/BARGE_HANDLING_BLOG/Entries/2016/11/8_Knots_and_whatnot.html

 

Tam

 

Thanks. I wonder... there's a chance I might be distantly related to you by marriage 😄 I think there was some rumour that my wife's Grandad Murrell was the son of a boating family.

[Ronaldo47]

There is always the "Highwayman's Hitch", plenty of instructions on how to tie one online. Pulling the free end releases it. I was never a scout, but learned it when I was in junior school from a page of knots in a Boy Scouts' diary I was given as a christmas stocking present.  Meant for tethering a horse so you can make a quick getaway, not sure how tightly it would bind under the high tension of a canal boat mooring.

Edited June 27, 2023 by Ronaldo47
typos

[Rob-M]

7 minutes ago, Ronaldo47 said:

There is always the "Highwayman's Hitch", plenty of instructions on how to tie one online. Pulling the free end releases it. I was never a scout, but learned it when I was in junior school from a page of knots in a Boy Scouts' diary I was given as a christmas stocking present.  Meant for tethering a horse so you can make a quick getaway, not sure how tightly it would bind under the high tension of a canal boat mooring.

I used a highwayman's hitch on one occasion and soon found the boat pulling caused it to bind so tight I almost had to use a knife to free it.

[LadyG]

5 minutes ago, Rob-M said:

I used a highwayman's hitch on one occasion and soon found the boat pulling caused it to bind so tight I almost had to use a knife to free it.

Agreed, we used such a hitch in a stable yard to tie well domesticated ponies under supervision. The knot can bind, it's known as a stable knot.

[tree monkey]

Incorporate a friction hitch in the system, use the hitch to tighten the lines, which means the dead line is available to extend if needed.

 

Prussic or blakes are 2 examples 

[IanD]

37 minutes ago, Rob-M said:

I used a highwayman's hitch on one occasion and soon found the boat pulling caused it to bind so tight I almost had to use a knife to free it.

Looking at the structure of the knot, this probably depends on the diameter of the post you tie it around -- a small diameter (e.g. post or dolly) will make it more likely to lock up, a big diameter (e.g. big bollard) will make it easier to free off.

[Ewan123]

1 minute ago, IanD said:

Looking at the structure of the knot, this probably depends on the diameter of the post you tie it around -- a small diameter (e.g. post or dolly) will make it more likely to lock up, a big diameter (e.g. big bollard) will make it easier to free off.

Interesting thought, I would want this at the boat-end of the line though as I always tie off on the boat to discourage fiddling from passersby.

 

16 minutes ago, tree monkey said:

Incorporate a friction hitch in the system, use the hitch to tighten the lines, which means the dead line is available to extend if needed.

 

Prussic or blakes are 2 examples 

I'll play with one of those I think. First thought is whether it would remain in place well enough with the motion caused by passing boats.

[tree monkey]

1 minute ago, Ewan123 said:

Interesting thought, I would want this at the boat-end of the line though as I always tie off on the boat to discourage fiddling from passersby.

 

I'll play with one of those I think. First thought is whether it would remain in place well enough with the motion caused by passing boats.

Properly dressed it should do, they routinely hold some lard arse tree surgeons

 

Seriously though I've incorporated a prussic in a pulling rope used to encourage trees to fall in my desired direction and not had a failure, tell a lie one did fail but that was vastly overloaded and was attached to a 4x4, it melted the rope

[rusty69]

Klemheist slides easier than a prussic. I spent three days stuck up our mast once after using a prussic.

Edited June 27, 2023 by rusty69

[tree monkey]

2 minutes ago, rusty69 said:

Klemheist slides easier than a prussic. I spent three days stuck up our mast once after using a prussic.

Old school prussic climber I am, never had one fail, had a few slowly, slowly creep after wet days on ropes full of green tree snot but plenty of climbers preferred blakes or kliemheist, they all use mechanical ascender now

[rusty69]

1 minute ago, tree monkey said:

Old school prussic climber I am, never had one fail, had a few slowly, slowly creep after wet days on ropes full of green tree snot but plenty of climbers preferred blakes or kliemheist, they all use mechanical ascender now

My god man. How many days do you spend up these trees?

Another good one is a rolling hitch.

[tree monkey]

4 minutes ago, rusty69 said:

My god man. How many days do you spend up these trees?

A wet day in a sycamore feels like forever, add a crown full of ivy and it feels like forever and a day

 

[blackrose]

2 hours ago, Ewan123 said:

Interesting thought, I would want this at the boat-end of the line though as I always tie off on the boat to discourage fiddling from passersby.

 

 

And the other reason to tie off onto the boat is that in flood conditions you may find you can't get to the bank and any knot you've tied bankside is underwater. And before anyone starts saying that's not a safe mooring that's a different subject. But on that subject I've had 2 home moorings which flooded regularly but were perfectly safe - as long as you know what you're doing.

Edited June 27, 2023 by blackrose

[magnetman]

very sharp machete for the emergency rope untying. 

[Clanky]

google ' slippery hitch'

 

 

[Alan de Enfield]

11 minutes ago, Clanky said:

google ' slippery hitch'

 

 

 

That took me to an adults only website _- interesting concept.

[Clanky]

19 minutes ago, Alan de Enfield said:

 

That took me to an adults only website _- interesting concept.

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