Engineering Possibility between 400 and 600 meters?

[speckledapple]

Hello,
I am a new member here but I joined because I am interested in learning all I can about certain engineering concepts that might help in my design.

First, I am curious about what type of materials would be best for building a ship that is between 400 and 600 meters long? This shape would be circular with a height of at least 60 to 100 meters. Thoughts?

[speckledapple]

What do you mean by "classic"?? The thought I had in mind was a ship that had a diameter of 600 meters. I would assume that it would be constructed in sections which is what I think you are talking about when you speak in terms of "classic". But the thing I am wondering about the most is the size and materials that can be used to tackle that size. Also, though I stated 600 meters it could end up being 1000 meters in diameter. The design is for a city ship (literally)