Thank you for the clearly stated information.Searchlights were not normally carried by merchant ships in 1912. They are a mixed blessing. They light up a limited area ahead of the ship, while ruining the night vision of lookouts trying to keep an allround watch. They also earn curses from other ships whose lookouts are blinded.
I don't know about modern freighters, but modern passenger ships carry searchlights, usually below the bridge and remotely controlled from the bridge. They are reserved for emergencies, such as searching for somebody overboard or for a small craft in distress.