Arrow should point to raw water pump..
That said your installation should be:
Seacock to male hose adapter to wire reinforced hose to a quality strainer (Groco or Perko bronze) to wire reinforced hose to raw water pump inlet..
Most early Catalina's were not built with true seacocks. The installation of a marelon thru-hull and ball valve threaded onto it is a very weak installation not coming anywhere close to the bare minimum strength to meet acceptable marine safety standards.
By placing more hard objects, such as a strainer, directly on top of the valve this only serves to create more leverage potential for snapping off the thru-hull fitting, a potential boat sinking event..
I am mot a huge fan of those plastic strainers for below waterline use as I have seen far too many split & crack..