Any Engineers Out There?

[Overtyme]

Thinking about NorthStar...

I know that that there are issues when it comes to large cranes and even moderate winds.

It got me wondering about NorthStar on sea days. After all, it is just a giant crane with a globe at the end.

Thoughts?

[iceburg1]

I suspect NorthStar will be shut down quite often due to high winds. On NCL, the ropes course is sometimes shut down even in moderately strong winds and NorthStar will be much more exposed to the winds than the ropes course. I cannot imagine NorthStar operating in even moderately windy conditions.

[hitaway4]

It will be able to handle alot more wind than a traditional crane.

 

The problem with winds and a traditional crane aren't so much to do with the crane as it does with what it's lifting. With a crane, you are lifting very heavy objects with cables. It's the swinging of the heavy object that often makes cranes during windy conditions unsafe, and hence, shutting them down in windy conditions.

 

Northstar is hard mounted to the "arm" with very thick heavy steel. (it's a welded spool piece) There is no swinging motion that would affect the capsule. (Look how thick the steel arm is) I don't have any of the engineering drawings in front of me, but it also probably has shock absorbers so the people inside don't feel like they are in a turbulent airplane.

 

I think it'll be operating in higher winds than you'd expect. I think wave height would be the higher concern.

[mo&fran]

I would worry as much about heavy seas rocking the ship itself.

[viper17d]

I would worry as much about heavy seas rocking the ship itself.

 

 

I agree it'll be much more resistant than you'd think.

 

Remember this ship is going out of Cape Liberty, not the Caribbean - high seas are guaranteed on every cruise. The boom of the thing is far larger (thicker) than you'd expect for the weight it's moving. I don't think RCI would put something on a ship that can't be used during sea days whatsoever out of NJ.

 

 

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[Dave85]

I don't think RCI would put something on a ship that can't be used during sea days whatsoever out of NJ.

 

 

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Right, I'm not an engineer but that's what I was thinking. They knew all along where this ship was going and clearly took that into account... they wouldn't put a feature on their brand new ship that they had a reason to believe would be out of service all the time.

[ColumbiaMDCanadian]

Yeah, there will definitely be days when they can't/won't operate it but I don't think they'll be as many as one might think.

 

hitaway4 pretty much explained it from a load perspective (it's all about the torque - on the arm as hitaway4 said but also on the base.

 

Cranes work very well when the load is directly below the arm. Once the load moves to the side, there's a vertical AND horizontal component to the force acting on the arm - and your typical tower crane arm bends/snaps.

 

The other image you see often is when (usually truck mounted) cranes flip over - and that's because if it's a truck crane it's NOT connected to anything or, if it's a tower crane (think high rise when they're starting construction), it's sitting on a long spindly thing. Neither applies here.

 

By the way, I also heard that the arm will have (has?) hyraulic dampers and its own stabilizer system to minimize the possiblity of, um, re-seeing what the special was at Windjammer that morning!

 

(Yeah, a civil engineer - though I don't work with tower cranes that often, let alone design them! :cool:)

[London-Calling]

It must have been quite a design challenge to put something that heavy on the top deck. Most of a ships weight (engines, fuel, provisions, water etc.,) are located very low down for stability.

 

Apparently locating Two70 directly above the engines was a challenge too.