my Answer is
academic
disciplines
challenge
construction
such as
withstand misuse
sea currents
In my view. I think the main challenge is to select materials such as steel are suitable for structural, corrosion resistance to sea water and the flow of water. And resistance to use, not a problem. If the problem is difficult to resolve because the sea.
In my view, I think the main challenge is to choose materials such as steel, it must suit the structure must withstand corrosion of seawater and sea currents and withstand misuse, a problem occurs. If the problem was difficult.