Singing Rock Double Stop Plus

[And]

This looks like an interesting bit of kit from Singing Rock - the Double Stop Plus http://www.singingrock.com/double-stop-plus

It looks like a Petzl Stop, but it also has an "anti-panic" feature and stops when the handle is squeezed in as well. It's as bit heavier than the Stop though- 421g v 326g. I'm not sure of the actual price as it looks like there are no UK stockists, but I've found it on a US website for $135 (?84 at today's exchange rate). Has anyone used one?

 

[Alex]

First thing I noticed about that is that it is loaded from the opposite side to a stop so I can see how it could be quite easily threaded wrong when someone has used a stop for many years.

 

[sluka]

It is not Singing Rock, it is anthron

http://anthron.si/index.php/zavora-dsd-plus.html

There is impossible to load a rope from the opposite side. I have it.

 

[ALEXW]

I bought one around 4 years ago because as a novice I was warned about "clutch and plummet" when using stops.
It is a bit of a faff to use, you put a loop of rope over a swinging bobbin but you can't really go wrong.
I was persuaded to use a simple so the Anthron has been unused since, I will leave it at the hut for you to play with Alex.

 

[Mark Wright]

Anthron are the manufacturer as sluka has mentioned. Singing Rock have their name put on it. This device has been around for at least the last 15 years with various companies having it branded as theirs.

They were originally designed for industrial rescue use. The loading of them can be a little confusing if your used to a Petzl Simple or Stop. The advantage of a Simple or Stop is that you can use the device as an ascender if used in conjunction with an upper ascender and footloop. You can't do that on this device as the tail rope comes out at the bottom of the device as opposed to the top.

Whilst it does have a 'Panic' function you do have to depress the handle fully to enable it. From considerable experience of using this device in an industrial environment most people find it a real struggle to fully depress the handle. It almost goes into 'freefall' just before it fully locks!!

If you want my advice, don't bother.

Mark 

 

[sluka]

Whilst it does have a 'Panic' function you do have to depress the handle fully to enable it. From considerable experience of using this device in an industrial environment most people find it a real struggle to fully depress the handle. It almost goes into 'freefall' just before it fully locks!!

It is panic function, not normal use. There is not any reason to control normal descent this way.

 

[Mark Wright]

As sluka mentions, the panic function is not something that is required in normal use, just when you panic grab, which is a natural reaction when you fall or lose control of your descent.

The device can actually be loaded in a number of different configurations. The EN conformances (EN341A & EN12841C) are based on the configuration as detailed on the side of the product. A large number of steeplejack companies in the UK bought the device thinking it would be safer to use that e.g. a Petzl Stop due to the 'panic function' but I'm not aware of it being used much these days in the industrial marketplace as this function didn't really work that well at all. These days the majority of industrial users prefer the Petzl ID as it has a 'panic' function that actually works as well as having an 'occasional user' failsafe. If you load it incorrectly it automatically locks. These however are a little bulky for normal caving use. 

One of the main disadvantages of the device is the way it is designed to be loaded. Because the tail rope comes out of the bottom of the device it can't be used as an ascender as I have already mentioned. Also because of this, It can't be used in a locking pulley type configuration, so its no use in a hauling system which is a real benefit of e.g. a Petzl Stop.

If you get it covered in mud, particularly the internals, the increase in friction makes it very difficult to descend with, even if you try to force the rope through the loaded device.   

Mark

 

[tamarmole]

As sluka mentions, the panic function is not something that is required in normal use, just when you panic grab, which is a natural reaction when you fall or lose control of your descent.

The device can actually be loaded in a number of different configurations. The EN conformances (EN341A & EN12841C) are based on the configuration as detailed on the side of the product. A large number of steeplejack companies in the UK bought the device thinking it would be safer to use that e.g. a Petzl Stop due to the 'panic function' but I'm not aware of it being used much these days in the industrial marketplace as this function didn't really work that well at all. These days the majority of industrial users prefer the Petzl ID as it has a 'panic' function that actually works as well as having an 'occasional user' failsafe. If you load it incorrectly it automatically locks. These however are a little bulky for normal caving use. 

One of the main disadvantages of the device is the way it is designed to be loaded. Because the tail rope comes out of the bottom of the device it can't be used as an ascender as I have already mentioned. Also because of this, It can't be used in a locking pulley type configuration, so its no use in a hauling system which is a real benefit of e.g. a Petzl Stop.

If you get it covered in mud, particularly the internals, the increase in friction makes it very difficult to descend with, even if you try to force the rope through the loaded device.   

Mark

Derailing the thread slightly  - whilst I appreciate that the locking effect of a stop is  theoretically useful in a pulley type set up such as a z rig surely the friction generated by a stop (or an ID for the matter) would completely knacker any mechanical advantage you might hope to gain rendering the exercise fairly pointless.

 

[Les W]

Derailing the thread slightly  - whilst I appreciate that the locking effect of a stop is  theoretically useful in a pulley type set up such as a z rig surely the friction generated by a stop (or an ID for the matter) would completely knacker any mechanical advantage you might hope to gain rendering the exercise fairly pointless.

I'm presuming that you mean that the friction would be prohibitive in comparison to a standard pulley.
The reallity is that the friction of a standard Petzl pulley is not that much less than the friction generated if you use only the bottom bobbin of a Stop as a locking pulley. There is plenty of friction in the rest of the system, the friction around the bobbin of the Stop is only a part of the total.
The Stop works fine in a hauling system as I can attest from personal experience.

 

[Mark Wright]

tamarmole,

You would generally only half load a Petzl Stop for use in a self-locking Z rig, however this would not be recommended by the manufacturer as it would render the device out of its EN341A conformance. The technique however has been used extensively and very successfully since the Petzl Stop was first intruded in 1979.

Whilst the friction generated with a Petzl ID is a little greater than with a half loaded Petzl Stop this is currently the most common method of rigging self-locking pulley systems in the professional rope access and rope rescue fields. The main advantage of this method over a, e.g. Petzl Traxion (various models) is that the system can be quickly converted into a lowering system, handy if the casualty gets snagged on the way up.

Far from the friction generated completely knackering the mechanical advantage, rendering the exercise fairly pointless, it is in fact a very efficient system and is used very effectively by thousands of industrial and rescue professionals every day.

Mark 

 

[tamarmole]

Thanks for the replies chaps.  Not sure I agree, my thinking being that Stops and IDs are primarily friction devices and they will introduce friction into a hauling system which is not a good thing. 

When I rig a z rig in a rescue context I tend to use a classic "A block" for progress capture comprising a pulley (usually a Petzl P50) and a jammer (usually a basic).  The down side as I see it is that it is more difficult to release (although by no means impossible) when loaded compared with a stop or an ID, but it gains significantly when it comes to reducing friction. 

"Life on a Line" 2nd edition, page 69 gives some fairly convincing figures regarding the amount of friction generated by a rescue pulley compared to a Stop of an ID.    To lift a 200KG load requires a force of 230 KG with a P50 pulley (180 degree bend), Stop rigged  for belaying (180 degree bend) requires 650 KG whilst an ID requires 630KG.

Given the purpose of a hauling system is to generate mechanical advantage I cannot see the logic of introducing high friction components into the system.

I carry a Micro Traxion and a pulley as part of my personal SRT kit and have used it in anger on a couple of occasions.  Traxions are difficult to release when loaded, however my main concern with them is that the teeth  dig into the rope when the rope is at it tightest angle around the pulley - I am always slightly worried about the effect of even a small shock load on the rope sheath.  For a rescue load (200KG) I would leave the Traxions well alone, that said for personal use I really rate them.

Ref:  Merchant D, 2007, Life on a line 2nd Ed, Lulu.com

 

[cavermark]

Tamarmole - the friction involved in a "z-rig" 3 to 1 using a stop or ID does not prohibit an average person hauling loads of 100kg or more.

There are added benefits such as easily being able to lower the load back down (e.g. stretcher snags on a protrusion on a pitch and needs lowering a short distance to be freed, pulling it up further is not possible).

 

[tamarmole]

Tamarmole - the friction involved in a "z-rig" 3 to 1 using a stop or ID does not prohibit an average person hauling loads of 100kg or more.

There are added benefits such as easily being able to lower the load back down (e.g. stretcher snags on a protrusion on a pitch and needs lowering a short distance to be freed, pulling it up further is not possible).

I concede that it is easier to lower off with a Stop or ID.

I doubt very much if one person could lift a 100KG load on their own for any meaningful distance using a z drag with either a Stop or an ID rigged for progress capture.

 

[cavermark]

I doubt very much if one person could lift a 100KG load on their own for any meaningful distance using a z drag with either a Stop or an ID rigged for progress capture.

I think Mark Wright has trained several hundreds of IRATA technicians by now, who have done exactly this..

 

[Mark Wright]

tamarmole,

If the intention is to reduce friction as much as possible then a Petzl P50 Rescue pulley locked with a toothed ascender is definitely one way to go, or better still a Petzl Minder pulley which is the most efficient pulley in the Petzl range, however, as you have already pointed out, it can be very difficult to release the ascender under load, particularly if the load has snagged and the hauling line has been effectively overloaded. The new Petzl Basic ascenders do not however work as well as the old style Basic as they don't have the double hole attachment at the top. Petzl would recommend the new ProTraxion for this purpose. These are a bit easier to release than the old style ProTraxion.

As I said before, the main reason why rope access and rescue professionals use devices such as the ID for hauling systems is for their ease of turning back into a lowering system. The same technique is used for rigging tensioned lines which can easily be lowered off in a rescue situation. If you carry on reading Dave Merchants excellent book you will find he affirms this.

If you were hauling a casualty up a free hanging shaft with no possibility of getting snagged then a ProTraxion would be an ideal device. Unfortunately not many caves are like that and there is usually always the possibility of snagging the casualty on the way up.

I can assure you that one person can easily lift a 100kg load a meaningful distance using a Petzl ID as the locking device. I say easily, you will get a bit of a sweat on doing it your own, so if you want to make it easier, get somebody to help you. As cavermark will probably attest, offshore rope access supervisors are required to be able to haul a casualty around 30m on most of the worlds offshore installations every day of the week.

Mark

 

[tamarmole]

Sceptical though I am next time I get the toys out I shall experiment.

Thanks for your all your comments.

 

[Cave_Troll]

it does work, the club teaches the same....

 

[Burt]

I had one of these for ages, used to use it on my zipwire which didn't have a "landing" area - so you had to abseil down the rope you were hanging off. I've now moved the zipwire so you land on the ground.

Anyway; it worked fine above ground but once I took it caving and with a good dollop of mendip mud inside, it would not budge. I had to revert to an Italian hitch mid-rope.

Much as I dislike petzl products (that's another rant altogether!), the stop works best underground.

 

[jo]

Kong also make a 'stop' like decender with this feature... I've seen it for sale from Sarless river, but can't remember the name of it off the top of head!

 

[Mike Hopley]

Kong also make a 'stop' like decender with this feature... I've seen it for sale from Sarless river, but can't remember the name of it off the top of head!

Kong Indy.