Port Side

What is the port side of a yacht?

On a yacht, the port side is the left-hand side of the vessel when you stand on board and face the bow. It is one half of the maritime world's most basic reference frame, with port to the left and starboard to the right, and unlike "left" and "right", it does not depend on which way the speaker is facing.

The convention has practical roots. Before stern-hung rudders became standard, ships were steered with a steering oar mounted on the right-hand side (the steerboard, from Old English stéor + bord), because most sailors were right-handed. With the steering oar to the right, vessels berthed against a quay with the opposite side facing the wharf, so cargo and passengers loaded across the port side. The OED cites usage from 1543. The Royal Navy formally replaced larboard with port in 1844.

On board a modern superyacht, port-side references remain in constant operational use. Under the COLREGS, the port side carries a red sidelight visible from dead ahead to 22.5° abaft the beam, while starboard carries green.

Why it matters for yacht owners

For an owner, port and starboard are the operating language of the yacht. Every General Arrangement plan, every bridge command, every mooring brief and every dock instruction uses these references.

The distinction also drives design decisions. Layouts often place galleys, crew passageways and service routes to port, leaving starboard for guest circulation and the principal cabin, though there is no rule. At night, the colour of the sidelights tells you what every other vessel around you is doing: a red light crossing right-to-left means you must give way.

Key facts

• Port is the left-hand side of a vessel when an observer on board faces the bow; starboard is the right.
• Both terms are fixed to the hull, not to the observer.
• Port carries a red sidelight, starboard a green sidelight, visible from dead ahead to 22.5° abaft the beam under COLREGS Rule 21.
• The term replaced larboard by Royal Navy order in 1844; the US Navy adopted the change in 1846.
• Etymology: from the side facing the port (harbour) during loading, OED records use from 1543.
• The COLREGS framework (IMO, 1972) standardises sidelight colours worldwide.
• Common mnemonic: "port" and "left" both have four letters; port wine is red.
• On many superyacht GA plans, galley and service routes run port, guest circulation starboard. Convention, not regulation.