The frog Walker SRT

[Laz]

Could your system be "backed up" with say a ISC rope grab instead of the croll or even the postioner. I would feel a lot more secure on two "mechanical" devices if one was closed throat same as the grab or positioner.

 

I only use the hand ascenders as a climbing aid, simply because they can easily fail.

 

Dean

 

From what you have said, I am assuming the reason for this is because you believe there is a risk of both cams completely unclipping at the same time. In this instance, yes, another cam or prusik (whatever type) will act as a fail safe.

 

BUT...

 

That control measure for that specific risk, must be measured against the actual application of that control measure, raising the risks in other areas.

 

Specifically:

 

The advantage of a single line to EN1891 Type A, of 11mm and true kernmantle, is required energy absorption; the ascenders will sever the sheath approaching safe limits for fall forces, and slip only 1m down the line (minimal risk of striking a branch in the fall). Such damaged ropes have full strength intact, and the climber can be lowered from the ground.

 

Many shelled cams will slip at forces well below this, or chop the line (depending on type). This means it could slip on to the core of rope and be ineffective (as would a prusik), or worse, damage the core.

 

An easy solution is for ascenders to have a hole under the cam to clip a small krab. This would be a simple and cheap solution to prevent the cam from opening. As on the Pantin and the old 'Clog' ascenders.

 

In the meantime, I'm not going to worry about both cams completely failing/unclipping at the same time.

 

It has been the misapplication and abuse of 'open throat' cams that has lead to accidents, not their proper application. They are not an 'unsafe' design. At all. And offer many solutions.

 

Particularly in the Frog technique.

 

But, even if the cams unclipped off of the line, they inherently want to close, and will do through inertia. I demo this on descent (without saying anything)

EG. When changing over to descent on the frog with a grigri, I just open up the upper cam and let it slide down with me (as its secured to the rope through the top holes). BUT, if I descend too quickly, inertia always flicks the cam back onto the rope to arrest the descent.

 

No-one ever picks up on this safety feature - they just laugh thinking its a crap system

 

 

So, even if both cams unclip at the same time, the inertia of a freefall should clip them back on pretty smartly.

 

All these comments are baring in mind the equipment listed at the start of this thread. This is a systems approach to compatibility, efficiency and safety.

[Laz]

I rarely use my SRT setup but it is handy to have for bigger ascents.Scott Sharpe designed it and it is great to use.I convinced my Boss( leading contractor) to buy 100 meters 10 mm Spectra which mostly sits around but a handy when needed.

 

Do you mean you climb on dyneema?

 

I wouldn't recommend that. Polyester nylon does just as good a job, with a lot less risk. That goes for any high mod fibre in life support.

[Dean Lofthouse]

Dean

 

But, even if the cams unclipped off of the line, they inherently want to close, and will do through inertia. I demo this on descent (without saying anything)

 

 

 

Thats something I never knew. I will look into that.

 

The setup I queried was Drews picture below, which, at the very least, if what you are saying about inertia and wanting to close is right, should have a crab through both top holes securing the rope into the throat?

[Laz]

Yes Dean,

 

In that picture, both cams should be secured to the rope through the top holes. I would also substitute the Blaze for a true 11mm kernmantle to EN1891 type A.

 

I might also clip the rope to the harness below the Croll, as explained in this thread a page or two back.

 

I've never seen or heard of anyone else mentioning the inertia thing. Its just an observation of mine. I first picked up on it when just opening the cam and sliding it down the line (because the top holes are secured) - once it picked up speed it would clamp to the rope every time.

 

Maybe it only works with the new Petzl cams with stiffer springs???

[nailer]

I like the way you promote effcient ergonomic work practice, but i can't help thinking access is only a very small part of our job.

 

I`m thinking the same. I also don`t think it`s a waste of time or energy just climbing up the tree `free-style`, but tied in. It`s nice to get warmed up slowly, figure out the finer details of your game plan and look around for any nasty surprises not visible from the ground.

 

Marc, your website is brilliant.

[Laz]

I`m thinking the same. I also don`t think it`s a waste of time or energy just climbing up the tree `free-style`, but tied in. It`s nice to get warmed up slowly, figure out the finer details of your game plan and look around for any nasty surprises not visible from the ground.

 

Marc, your website is brilliant.

 

Your thinking is in keeping with our own opinions - there is more to ergonomic working than just ascent. But we have to start somewhere of course.

 

Climbing a ladder and climbing the tree are both very ergonomic practices compared to others. Like I've said all along, ergonomics is not about avoiding effort, its about efficient effort.

 

But you often get those awkward sections with no branches. What I like about the Frog walker is the ability to climb the tree like a ladder with safety when possible, and revert to Frog when not. The pity about the vid that started this thread, is it ended just as I reached the branches - I climbed another 30ft on the frog walker by climbing the tree.

 

BUT

 

This thread wasn't started to discuss ergonomics, as its too complex to do it justice on-line. It was just to show the frog Walker for those that are dabbling with SRT, but haven't seen a frogwalker system.

[DrewB]

Thats something I never knew. I will look into that.

 

The setup I queried was Drews picture below, which, at the very least, if what you are saying about inertia and wanting to close is right, should have a crab through both top holes securing the rope into the throat?

 

im glad i put that picture up as ive now changed the setup slightly and made it safer-i wouldnt of realised what i was doing wrong without your guys info, so cheers for all the advice. and a new kernmantle rope arrives tomorrow so itll be good to see how different it feels. once again, thanks for the advice, especially paolo.

[Marc]

I'd like to see throw line, foot locking and srt techniques taught at a basic nptc level.

On my basic tree climbing and aerial rescue I spent a week making monkey fists to reach the first branch then rope over rope to the top and that was basically it.

It took my participation in forums like these and working with other climbers to learn other ways of access and climbing once in the canopy.

 

The difficult thing with trying to learn these techniques online or from working with others is to fully grasp how to set them up appropiately.

[Dean Lofthouse]

The difficult thing with trying to learn these techniques online or from working with others is to fully grasp how to set them up appropiately.

 

Thats one of the reasons we organised a fun climb get together in my wood.

 

It puts all the things you hear and see online into practice. Loads of people turned up and shared ideas. Some toys were available to play with and just by watching others climbing and their techniques we learnt quite a lot between us.

 

Hopefully we will put another together soon, it was good fun.

[bob]

Thats one of the reasons we organised a fun climb get together in my wood.

 

It puts all the things you hear and see online into practice. Loads of people turned up and shared ideas. Some toys were available to play with and just by watching others climbing and their techniques we learnt quite a lot between us.

 

Hopefully we will put another together soon, it was good fun.

 

camping beer and a night climb challenge would be good