Took longer than expected, in order to restage 'To The Lifeboats' with a tilting stage, but we have a show!
At one point, there were 36 people on the tilted stage. Assuming for the sake of argument, that each person weighed 160 pounds, that works out to roughly 36 x 160 = 5760 pounds, or nearly three tons. Add in the weight of the stage itself (600 pounds?) and that's more than three tons.
'To The Lifeboats' was restaged so that there won't be more than about 24 people on the tilted stage at any one time - roughly two tons civilian cargo, maximum.
I've been worried about two types of potential failure:
- rigging failure, such as snapping cables; or,
- tilting stage structural failure, such as snapping 2 x 12 timbers.
The second kind of failure is more likely. The stage noticeably bows: it's hard to bend coupled 2 x 12 timbers depthwise, but the bend is there. After trying the maximum load test last night, the tilt angle was increased for 'Still,' and several of us got on the tilted stage, but abruptly left, when pops were heard on the rear coupled 2 x 12. Apparently the front coupled timber had already been stiffened with steel, but not the rear one, where the pops were heard. Today, the rear coupled timber will be stiffened as well. Even if there is a catastrophic failure of the coupled timbers, the presence of the broken timbers themselves would blunt the stage's fall, and therefore help limit the damage. It would be bad, and embarrassing, but probably not catastrophic.
I was puzzled why a load of fewer people at a greater tilt angle would pose a greater problem than many people at a shallow angle. Chris Neff said "well, the torque is greater," but I don't think that's correct. Still, there is a shift of pressure within the coupled timbers, less contact of the timbers with the floor, and that pressure shift may somehow be to blame. [update: with the presence of blocks, the hypothesis of greater torque becomes more plausible - the axis of rotation is not at stage level, but rather at the top of the block. Therefore, a steeper stage will have a greater moment arm, as the block is moved closer to the bottom end of the tilted stage.]
The design of the tilting stage is quite impressive: clever forethought! Some carping has been overheard - one cast member suggests a better design might be a counterbalanced stage rotating around a central pivot, and elevated several feet above the main stage, in order to give room for movement, but that idea hasn't been clearly thought through. Such a design would place the entire weight of the stage (plus counterbalance) on just two points - a potentially dangerous concentration of weight, especially with musicians in the orchestra pit below. McElroy's design distributes weight much better.
Oh yes, and did I mention that the Titanic cast is sounding better all the time? That kind of improvement gets overlooked when dealing with a novel apparatus.
Last night, walking the dog past the 24th Street Theater at 2:30 a.m., I noticed the lights burning. Ah! I know what they're up to! "Baby" opens tonight at Runaway Stage Productions!