A Lesser Known Prussik Knot

[Joonsy]

For those that like knots & ropework here is a lesser known prussik useful for one particular reason, you can release it from distance even when it's weighted. To release most types of prussik you have to lay your hand on the actual knot itself, if the prussik is out of arms length you will not be able to release it, also many (though not all) prussiks cannot be released while they are holding weight. With this one you can release and slide the prussik even when you cannot reach the knot and also while it is bearing weight too. The knot was originally invented by the Canadian climber Robert Chisnall for rescue work however I won’t detail that here but note that this prussik should not be used for climbing and I have posted it for members with an interest in knots & ropes only. First a brief description of finished knot:- the completed knot has two seperate lengths of cord trailing from it which can be any length, one cord will lock the prussik when weighted and the other cord will release and slide the prussik if pulled, when the prussik is weighted/locked it can still be released by pulling the other cord, when you loose the release cord the prussik will grab and hold again. The knot works better on some ropes than others depending on their properties.

Self-explanatory steps below to tie it, (it can also be tied in a different way by doing the wraps first which has some advantage bit I will leave that out for now) :-

The pic below is the knot completed, the gripping part (prussik) is the two last wraps around yellow rope, you can add more wraps for a more secure hold but too many wraps will make it harder to release, pic shows two wraps but three may be needed to hold on some ropes, rope type will dictate how many wraps are needed to hold without slipping just add more or less as necessary. It MUST be tied correctly to work.

Dress the finished knot and it will look like this, one cord will lock the prussik when weighted the other cord will release it when pulled.

View of same from above

And view of same from other side

Knot can be loosened and untied quite easily after loading by bending the loops either side of rope to release tension like below.

There you are, something for you to play with if the bank holiday is a washout

 

[Macaroon]

Excellent, a new one on me; thank you for this.

 

[sandbender]

Thanks for this, I'll have a play with it over the weekend.

 

[cave_dweller]

Nice one, thanks. Slide and grip knots are often useful, I'll have a bash at this one.

I once found a description of something termed a "Penberthy Prussik" on the outdoor idiots website. The site has gone, and I can't find any reference to it anywhere else.

 

[Joonsy]

Excellent, a new one on me; thank you for this.

Thanks for this, I'll have a play with it over the weekend.

Thanks Macaroon & Sandbender for your replies, have fun

Nice one, thanks. Slide and grip knots are often useful, I'll have a bash at this one.

I once found a description of something termed a "Penberthy Prussik" on the outdoor idiots website. The site has gone, and I can't find any reference to it anywhere else.

Thanks for reply Cave-Dweller yes they are fun i know a few more which are not very well known and may post them at a later date. The Penberthy is tied in a single strand of rope as opposed to a continuous loop like the classic prusik or klemheist, a single strand is wrapped around a rope four of five times and then finished by the ends being tied together close to the wraps with a bowline, crucially only the one strand is load bearing for knot to work properly. The knot features in a book by Nigel Shepherd called The Complete Guide To Rope Techniques.

 

[Joonsy]

here you are Cave-Dweller, just knocked up a quick photo for you of the Penberthy, Very important to note that only the one end is used to take weight, the blue cord exiting on the left of knot is taking the weight, the blue cord exiting on the right of knot is just left loose, sometimes a back-up overhand knot/fishermans knot is added to the loose end for safety which is not shown in photo (just post if you need further instruction on the knot) As with all prussiks use the neccessary amount of wraps to stop knot slipping.

 

[Tommyd345]

Im guessing the rope you are tying around (yellow) can be anything? Or is it only for ropes?

 

[Goatboy]

Nice neat presentation and clearly explained. Must admit that my rope work is very rusty these days as I no longer climb so it's good to see wee refreshers now and again. One of my favourites and quick to knock up and handy in lots of situations is the Bachmann knot. Got me out of a few sticky ones in the past.

 

[Joonsy]

Im guessing the rope you are tying around (yellow) can be anything? Or is it only for ropes?

Most prusiks work best on rope and it’s what most are designed to do, and they work best when the prusik cord is a smaller diameter than the rope it is fixed to. They work best on rope because they can dig in and strangle it gripping it better than say a solid wooden pole which doesn’t reduce in diameter when squeezed like a rope does, even different types of rope can affect how good a prusik grips due to their different properties. The key to all prusik knots is the amount of wraps around the item it is fixed to, if the knot slips you just add more wraps, some ropes may only need two or three wraps of a prusik to hold while other ropes may need five or six wraps for the prusik to hold. Generally speaking hard firm rope needs more wraps than soft rope. However there is no reason why a prusik can’t be used on other things if you can actually get it to hold you just have to experiment with the amount of wraps to find out. Note that a prusik is designed to work with a lengthways/paralell force, for fixing a cord/rope to something like a wooden pole when the force is loaded lengthways paralell to the pole there are two really good knots specifically invented for that, one is called the ''sailors gripping hitch'' and the other is called the ''icicle hitch'' (which as the name suggests can even hold on a tapering pole). I use the sailors gripping hitch myself on both ends of a bow for the bow drill fire-lighting.

Sailors Gripping Hitch for a lengthways pull on a pole (good for bow drill)

Icicle Hitch for a tapering pole

 

[Joonsy]

Nice neat presentation and clearly explained. Must admit that my rope work is very rusty these days as I no longer climb so it's good to see wee refreshers now and again. One of my favourites and quick to knock up and handy in lots of situations is the Bachmann knot. Got me out of a few sticky ones in the past.

Thanks Goatboy, yes the Bachmann is handy when you have a spare crab

 

[EdS]

Technically the is only prusik and that like the others isnt a knot but a sliding hitch ��

 

[Joonsy]

Technically the is only prusik and that like the others isnt a knot but a sliding hitch 😆

i ain't got a dictionary for gobbledygook

 

[falcon]

The Sailor's Gripping Hitch is a new one for me....off to play in the shed tomorrow ...👍

 

[Joonsy]

The Sailor's Gripping Hitch is a new one for me....off to play in the shed tomorrow ...

here it is and how to tie Falcon, it's the second one down just scroll down to it, have fun

http://notableknotindex.webs.com/sailorhitches.html

 

[falcon]

here it is and how to tie Falcon, it's the second one down just scroll down to it, have fun

http://notableknotindex.webs.com/sailorhitches.html

Many thanks....there's a few on Google and that one's saved on my phone should I need a prompt ! I'm particularly intrigued by your use of it for the bow drill cord attachment

 

[Joonsy]

I'm particularly intrigued by your use of it for the bow drill cord attachment

photo doesn't show detail very well sorry but it gives you the idea, both ends of bow have a sailors gripping hitch (i have also added an overhand stopper to the loose end where it exits knot as it helps to stop loose end slipping), just slide the two end knots to desired length and it holds firm. Like this you do not need to either have a fork on bow nor cut a groove into the bow, knot holds firm enough by itself without those.

 

[falcon]

photo doesn't show detail very well sorry but it gives you the idea, both ends of bow have a sailors gripping hitch (i have also added an overhand stopper to the loose end where it exits knot as it helps to stop loose end slipping), just slide the two end knots to desired length and it holds firm. Like this you do not need to either have a fork on bow nor cut a groove into the bow, knot holds firm enough by itself without those.

Brilliant ! I reckon you might start a trend...!

 

[Tommyd345]

Another thing, is it possible to adjust the tightness of the bow drill cord with this knot? I am still searching for a good knot that I can tighten/ loosen by just sliding along?

 

[Joonsy]

Another thing, is it possible to adjust the tightness of the bow drill cord with this knot? I am still searching for a good knot that I can tighten/ loosen by just sliding along?

Yes that's why i use the knot, just slide the knots along the bow so cord is at the desired length, the further apart the end knots are the tighter the cord will be, no need to untie the knots you just slide them. When tensioned as you are bow-drilling they will hold firm. I also add an overhand stopper knot (any stopper knot will do figure of eight etc) to the loose end as well which improves the knot even further, keep it close to the main knot.

tie the cord to both ends of bow with knot tied like this both ends

 

[Joonsy]

As some interest has been shown in the knot above (Sailors Gripping Hitch) i thought i would add a step-by-step guide on how to tie it (with optional improvements).

This is the standard knot completed.

When dressed it will look like this.

An optional improvement is to tie a stopper knot in the loose end close to main knot (if knot and cord is likely to be left on pole for some time such as a bow drill this improves knot, however if knot is used for things like sailing when it is likely cord & knot will need to be renomoved/untied regularly from a pole/spar then it's best not to add a stopper knot to loose end).

Another optional alternative which also improves knot is to to make a final twist with loose end as below, this method has the advantage of adding more friction thus improving knot's holding power.

Pic below shows the above method comleted and dressed.

Or to make the final twist as above you can also alternatively do it as in pic below (the standard knot is fine, these alternatives adding another twist just adds more friction to knot and helps stop slippage).

And that method completed and dressed will look like pic below (always leave a longish tail on loose end).

Thanks for looking