Official Answer
Answer
The removal notch is a small cutout or 'scallop' on the end of a spiral retaining ring that allows a screwdriver or specialized tool to get behind the ring to pry it out of the groove. In subsea equipment, where visibility is low and tools are manipulated by ROVs (Remotely Operated Vehicles), the notch must be large enough to be easily engaged. However, the notch geometry must be carefully designed to avoid creating a stress riser. A radiused notch is preferred over a sharp V-notch to maintain the fatigue strength of the ring, especially in applications subjected to cyclic axial loading.
