Hanging Automated Fixtures Question

[EHansenLX]

So I'm doing a show in a couple months and I'm trying to come up with a good way to hang 2 Martin Mac 700 Profiles.

We have 3 catwalks above the house (see attached diagram for more detail). My plan is to hang the fixtures between the 1st and 2nd catwalk by hanging them on 1.5" Steel Pipe that spans the distance between the two catwalks. The pipe would be attached with Cheeseboro clamps on both bridges.

First question:

1) Does this plan for hanging seem like it will work? Any thoughts or input?


Second question:

2) I'm not able to get to the hanging positions on the catwalks from underneath, so I'll have to hang the fixture from above essentially. The only way I can see doing this is attaching some good safety cables and have a couple strong guys hold the fixture up while it's being tightened onto the pipe. Any other ideas on this?

Thanks for the help!

 

[MNicolai]

1) Probably. Depends on the span length between the catwalks. One fixture per pipe isn't that much load, but if we're talking an 8' span between catwalks that's much different than if we're talking 20'. Since you will only be supporting the pipe at the ends, I would definitely use a continuous, non-spliced, non-coupled pipe.

2) Not knowing your venue or what kind of obstacles you may have to get around, my instinct would be to install your clamps up top, hang sheaves from above those points and drop ropes down. Hang the fixture and dress DMX/AC cables at ground level. With 2 people on each catwalk, one each for hoisting, and the second each for positioning and locking the clamps down, hoist the pipes into place and tighten the clamps. Safety the fixtures to the pipe, and both ends of the pipe to the catwalks or other nearby structure. Pull your dangling cables up and connect them into your system.

 

[theatricalmatt]

Yikes. Depending on the span and the weight of the fixture, you might want to use truss, rather than pipe. Also, if the Mac 700s are going to be closer to the catwalk -- really, you need to dimension that drawing! -- you might be able to get away with a pipe that bridges the upstage and downstage handrails of just Cat 2, and cantilever the unit off of that pipe. (It may also depend on whether you can run power and data from Cat 2, or if it ha to jump from Cat 1.)

If you've got access to roof steel, or there's an overhead pipe or other structure, you could hang a pulley or block and fall off that, and use that to hoist the 700 into position.

 

[Lextech]

Without a scale there is no way for anyone to answer properly. As Matt says truss might be required. You might need schedule 80. Personally when I do anything like this I prefer to have two connection points per side and will attach to both handrails of the catwalk on both sides of the span. The best way to approach this is to get a qualified rigger to come into your space and have them help you. If this is over the audience my last statement goes double.

 

[EdSavoie]

I was wondering what all the fuss was about hanging one of these, then I looked it up and realized it's well over 70 pounds a unit...

 

[EHansenLX]

Wow, thanks for all the input! I've attached a dimensioned diagram. The span is 11' and the Martin MAC 700 Profile weighs 76lbs.

I've looked at the space and I don't have access to any roof steel or structure above the hanging point, so hoisting the fixture into position isn't an option. I may need to look into alternate hanging locations...

 

[sk8rsdad]

Assume all the usual caveats have been stated about always being safe and that a pipe is suitable to span the gap...

If you can carry the MLs to the catwalk then the easiest way to rig them is to use a pipe that is a little more than 1.5 times longer than you need to span the catwalks. Snug up the pipe so the extra length is at the catwalk to which the MLs have been carried. Rig the light on the pipe, cable it up with whatever slack , then carefully loosen the clamps, slide the pipe to it's intended position, then tighten all the cheeseboroughs.

 

[derekleffew]

Why does the pipe have to span across catwalks? Consider a "sidearm on steroids" as discussed in this thread: https://www.controlbooth.com/threads/hanging-moving-lights-in-a-weird-position.31372/ .

 

[EHansenLX]

Thanks for the link to that other thread - answers pretty much all of my questions

I figured that the strongest option would be to run pipe all the way across, but if I could mount the fixture vertically, then I think that would work as well.

Thanks, everybody!

 

[JD]

I would second the opinion of using truss.
Because they move, there is momentum involved and they are going to want to twist and slip. The truss suggestion is not so much one of a safety concern as much as keeping alignment.
As an alternative, using two sections of pipe at each location would allow you to clamp to both to help minimize the fixtures desire to twist.

 

[porkchop]

I'm not a big fan, but I've seen dumber things work for years. I would make sure the people responsible for health and safety for your venue are well aware of what your plan is before you get too invested in it. You wouldn't want to be told to take it down the day before opening after the House Manager realizes it's over the audience (obviously that's a hypothetical that may not apply directly, but you get the idea).

Alternatively the manual for the Mac 700 says it can be hung in "any orientation". Have you considered hanging it sideways (that is with the base running vertically rather than flat) from the side of the catwalk. It's still less than ideal, but given the information we have it seems safer that a pipe running between two catwalks

 

[SteveB]

Maybe a cantilevered side-arm.

 

[derekleffew]

Maybe a cantilevered side-arm.

Thank you @SteveB . That's exactly what I was suggesting in the other thread. Sometimes an illustration is necessary.

(Though I'd probably put the light on the inward (nearer the catwalk) side of the hypotenuse.)

 

[SteveB]

Thank you @SteveB .

(Though I'd probably put the light on the inward (nearer the catwalk) side of the hypotenuse.)

Yup, that's a good suggestion.

 

[Jay Ashworth]

As close to the second bridge as it is, is there some reason why you can't *mount it on the second bridge* that you mentioned and I missed?

 

[MikeJ]

I will not tell you what to do or give you advice. But I have would personally be fine with that setup. I have done similar in the past. There will not be twisting or slipping if you tighten all of the clamps. It might rock a bit from the play in the joints of the cheesbouroghs, but it will be even less pronounced than hanging movers in linesets.

 

[EHansenLX]

I think what I'm going to do is cheeseboro a vertical pipe to the two pipes of the catwalk (see Steve's diagram) and then mount the fixture vertically on that pipe. As has been said, less than ideal, but I think it will work just fine for what I'm doing.

 

[SteveB]

Don't mount vertically. The fixture's not designed for that, wants to be base up or down.

 

[MikeJ]

Don't mount vertically. The fixture's not designed for that, wants to be base up or down.

Most fixtures can be hung vertically, but it really screws with your sense of pan and tilt. I don't like it at all, personally.

 

[porkchop]

Don't mount vertically. The fixture's not designed for that, wants to be base up or down.

It's not my favorite, but like I said earlier the manual for the fixture in question specifically states it can be rigged in "any orientation". Not all fixtures are designed for this, but this one is.