Im sure there are many who know about this, i have been using this little trick for a long time now and just thought i would share it.
Moving your crewmen to their individual slots in the crew management screen can be a real exhausting pain in the butt sometimes. however...
If you take a sailor or petty officer, and click and draft to move him to the
officer slot in any given compartment within the crew management screen, the sailor or petty officer will automatically be dropped in the next available open crewman slot for that compartment
This saves time over trying to fit him into the tiny crewman slot