$(15$ points$)$ There exists $8-$lines, made of extra improved plow steel, having a diameter of $1\mathrm{.}125$ in $.$ between the crown and travelling blocks in the hoisting system of a rig. Determine the maximum casing length supported by the rig safely if a safety factor of $1\mathrm{.}75$ based on dynamic loading condition is required. Class C$-75$ casing has a unit weight of $72lb\frac{m}{f}t.$ Ignore the buoyancy effect caused by the drilling fluid.