Flying climbable ladder

[Ech725]

So we've built a 20' ladder that is reinforced an that an actor may climb a few steps. Ladder flies in and actor climbs 4 steps. The issue is that when the actor climbs it, the top half moves. Any suggestions on fixing the shaking?
We are thinking about increasing the base and attaching a line from the batten that ratchets to a stage screw.

 

[Footer]

Um... nothing is going to fix it if it is flying from a single batten. Unless you can build the base bigger and make sure the thing can support itself (and the actor) without the rigging your going to get sway. All the rachet strap will do is put more strain on your rigging. Also, without the right safeguards in place this could get to be a real issue. If the ladder is being partially supported by the rigging when the actor is on it, you could have an out of weight issue very easily... very quickly. I would re-engineer it so the ladder can be totally self supporting and then fly it. When the unit is landed no extra forces should be introduced into the rigging. The weight of the actor should be transferred into the deck and not into the rigging.

 

[gafftaper]

Agreed. I would design some sort of fold out support structure which you can use AFTER the ladder is flown in. The ladder should not put any pressure on the fly system once it hits the ground.

 

[LavaASU]

Yup. Rope locks are designed to keep an in-weight set from drifting, not to hold an out of weight condition. Either the lineset needs to be secured (consult an experienced rigger) before he gets on the ladder, or it needs to be entirely supported on the ground.

 

[BillConnerFASTC]

Is this a straight ladder? And is the base on the floor at all times when the actor climbs and is on the ladder?

 

[Tex]

Yup. Rope locks are designed to keep an in-weight set from drifting, not to hold an out of weight condition. Either the lineset needs to be secured (consult an experienced rigger) before he gets on the ladder, or it needs to be entirely supported on the ground.

What if it's a motorized lineset?

 

[Ech725]

Yes the ladder is completely on the deck when the actor climbs it.

 

[sk8rsdad]

What if it's a motorized lineset?

The out of balance lineset issue goes away but other issues come to the fore. You are still left with the issue of stability of the ladder. Once you introduce any dynamic load on the system it is very difficult to know what will happen. It really needs to be seen in situ by a competent rigger.

Another risk is accidentally unweighting the batten if the ladder takes up any of its weight. That can cause the wire rope suspending the batten to jump out of the grooved winch drum, which could be unsafe and certainly unhealthy for the rigging system.

 

[BillConnerFASTC]

If the ladder is sitting on the floor when climbed on, I think moist of the gravity or vertical load on the lineset issues go away or at least are minor. It's really about stabilizing the top. If the ladder could be rotated - then lines to stabilize the batten to the sides of the stage would probably be enough. If across - perhaps it could be guyed to rings inset in the floor - like a volley ball net or high bar in a gym (use to be anyways). The line set is doing nothing except raising and lowering the unloaded ladder. Would it be that hard to have two or four guy lines anchored?

Would be interesting to know if there were any opportunities - like a trap room - to stabilize it that way - a pole or deep socket into or through the floor.

Good luck. Opening night is approaching!

 

[Ech725]

Well we managed to increase the base from 12" to 28" and that really helped. It still wiggles but it's better. We opted to not do the ratcheting because we didn't want to add more weight to the line from the ratcheting force.

 

[josh88]

You till haven't answered if this is a straight ladder or an a frame type that supports itself. It sounds like a straight ladder. You get the danger of adding a person worth of weight pulling down on a batten right? If you have a person on this and the rope slips through then the best possible scenario is that ladder and person come crashing to the stage as it caves in. Don't just assume the rope lock will be able to hold the added weight of the person safely just because it has every other time you've tried it.


Via tapatalk

 

[BillConnerFASTC]

You till haven't answered if this is a straight ladder or an a frame type that supports itself. It sounds like a straight ladder. You get the danger of adding a person worth of weight pulling down on a batten right? If you have a person on this and the rope slips through then the best possible scenario is that ladder and person come crashing to the stage as it caves in. Don't just assume the rope lock will be able to hold the added weight of the person safely just because it has every other time you've tried it.

.
Via tapatalk

If the straight ladder is sitting on the floor, why isn't the weight of the climber on the floor as is the usual case, and on the batten instead? Yes, as the ladder becomes more horizontal there is some vertical load on the batten, but it never exceeds half, and by that time the ladder is horizontal. The trick is simply keeping it near vertical and the load will all be on the ladder.

What are you seeing I'm not? If the ladder is leaning against the eave of my house - with a `1:3 or 1:4 slope - there is no significant vertical load on the eave.

 

[DuckJordan]

Actually there is. Use the pythagorean theorim to figure out the math...

 

[BillConnerFASTC]

I use vectors but the vertical load is just not significant. I can push myself away from the eave with one hand with little effort - and that is nearly all horizontal.

Let the ladder transfer the vertical load to the floor and figure out how to laterally brace it. The counterweight rigging is just for storage.

Plus there are multiple means to secure the arbor so that additional static vertical loads are properly handled without the force being put on the rope lock or t-bar (or j-bar).

 

[josh88]

I use vectors but the vertical load is just not significant. I can push myself away from the eave with one hand with little effort - and that is nearly all horizontal.

Let the ladder transfer the vertical load to the floor and figure out how to laterally brace it. The counterweight rigging is just for storage.

Plus there are multiple means to secure the arbor so that additional static vertical loads are properly handled without the force being put on the rope lock or t-bar (or j-bar).

Thats the thing though if, it isn't vertical and it ends up leaning then at least some of that weight is getting transferred to the batten, and just because there are ways to secure the arbor doesn't mean the the op is doing that. I imagine scenarios worse than are usually the case just because you don't know what somebody might do when you aren't looking. I was just stressing that they step back and make sure what they have is safe. Thats all.

 

[z2oo]

If the ladder can be re-engineered, an A-frame type deal could be substituted for what I'm assuming is a totally straight ladder, right? Unless I'm missing something, this seems to be a sure way to allow the ladder to support itself once flown in.

 

[Dreadpoet]

Wierd...I just saw this on So You Think You Can Dance. They had a similar ladder height...but ladder had 45 degree supports at bottom and bolted onto a plywood base which gave it lower stability with fly lines pulled taught for upper stability.