What flies on the bow of a ship when it is in port?

When a ship is in port, the Union Jack is traditionally flown on the bow. This practice signifies that the vessel is in a harbor and serves as a visual cue that distinguishes a ship as a Royal Navy vessel, or in some instances, a merchant ship under British registration.

The Union Jack is flown in situations specifically to denote a ship's presence in port, particularly when the ship is not under way. It is important to recognize that this flag signifies the nation of the vessel and enhances the understanding of maritime customs and traditions related to flags.

In contrast, the national flag typically flies at the stern of the ship, and the ensign is usually displayed at the stern when a vessel is on the high seas. The jack staff is a separate flagpole located at the bow, specifically used to display the naval jack, which is often the same as the Union Jack when in port. Understanding these specific usages of flags helps in grasping the naval insignia protocols and the traditions associated with maritime operations.