So, you know all the parameters, which are going to be involved in the calculation of velocities and accelerations. Like all these things which are listed here, it is better keep them here and then you can just calculate. Suppose, if that is, if you are adopting the conventional practice of calculations. Once, this is obtained then, you have to calculate your maximum orbital velocity. Maximum orbital velocity will be at the free surface that is, in this case at the still water line that is when z equal to 0. So, you know the expression for u, then just use that value z equal to 0. So, that will boil down to pi H by T into 1 by tan h k d.