Q: I am using class H_CAT and a buoy midline.  Why is my spring buoy floating in air?
REV 7.04

A: Your problem is that you are using a buoy with a H_CAT. The manual says

• ·       A H_CAT ignores both the bottom and the water line, so a spring buoy cannot be used here.
• ·       By default, a H_CAT ignores the weight of the element so that it is really a tension only SL_ELEM. A value of EXACT for FLAG considers the weight.