Editing Navigation light (section)

==Marine navigation==
In 1838 the [[United States]] passed an act requiring steamboats running between sunset and sunrise to carry one or more signal lights; colour, visibility and location were not specified.

In 1846 the [[United Kingdom]] passed the [[Steam Navigation Act 1846]] ([[9 & 10 Vict.]] c. 100) enabling the [[Lord High Admiral of the United Kingdom|Lord High Admiral]] to publish regulations requiring all sea-going steam vessels to carry lights.<ref>{{citation|title=9th and 10th Vic. c. 100: "An act for the regulation of steam navigation, and for requiring sea-going vessels to carry boats|url=https://archive.org/stream/statutesunitedk39britgoog#page/n674/mode/2u|access-date=6 July 2019|pages=623–624}}</ref>  The admiralty exercised these powers in 1848 and required steam vessels to display red and green sidelights as well as a white masthead light whilst under way and a single white light when at anchor.<ref>{{London Gazette | issue = 20876 | date = 11 July 1848 | page = 2606 | title = Steamers' lights – to prevent collision}}</ref>

In 1849 the U.S. Congress extended the light requirements to sailing vessels.

In 1889 the United States convened the first International Maritime Conference to consider regulations for preventing collisions. The resulting Washington Conference Rules were adopted by the U.S. in 1890 and became effective internationally in 1897. Within these rules was the requirement for steamships to carry a second mast head light.

The international 1948 Safety of Life at Sea Conference recommended a mandatory second masthead light solely for power-driven vessels over {{convert|150|ft|0}} in length and a fixed sternlight for almost all vessels. The regulations have changed little since then.<ref>''Handbook of the Nautical Rules of the Road'' Llana and Wisneskey</ref>

The [[International Regulations for Preventing Collisions at Sea]] (COLREGs) established in 1972 stipulates the requirements for navigation lights required on a vessel.

===Basic lighting===
[[Watercraft]] navigation lights must permit other vessels to determine the type and relative angle of a vessel, and thus decide if there is a danger of collision. In general, sailing vessels are required to carry a '''green''' light that shines from dead ahead to 2 [[Points of the compass|points]] ({{frac|22|1|2}}°) abaft<ref group="note">[[wiktionary:abaft|abaft]]: to the rear/closer to stern/'aft'</ref> the beam on the [[starboard]] side (the right side from the perspective of someone on board facing forward), a '''red''' light from dead ahead to two points abaft the beam on the port side (left side) and a '''white''' light that shines from astern to two points abaft the beam on both sides. Power driven vessels in addition  to these lights, must carry either one or two (depending on length) white masthead lights that shine from ahead to two points abaft the beam on both sides. If two masthead lights are carried then the aft one must be higher than the forward one.

Small power-driven vessels (under {{convert|12|m}}) may carry a single all-round white light in place of the two or three white lights carried by larger vessels, they must also carry red and green navigation lights.  Vessels under {{convert|7|m}} with a maximum speed of less than {{convert|7|kn}} are not required to carry navigation lights, but must be capable of showing a white light.<ref>{{Cite web |title=Amalgamated International & U.S. Inland Navigation Rules: Part C - Lights and Shapes |url=https://www.navcen.uscg.gov/navigation-rules-amalgamated |access-date=July 18, 2022 |website=United States Coast Guard Navigation Center}}</ref> Hovercraft at all times and some boats operating in crowded areas may also carry a yellow flashing beacon for added visibility during day or night.

===Lights of special significance===

In addition to red, white and green running lights, a combination of red, white and green mast lights placed on a mast higher than all the running lights, and viewable from all directions, may be used to indicate the type of craft or the service it is performing. See "User Guide" in external links.

*Ships at anchor display one or two white anchor lights (depending on the vessel's length) that can be seen from all directions. If two lights are shown then the forward light is higher than the aft one.
*Boats classed as "small" are not compelled to carry navigation lights and may make use of a hand-held [[flashlight]].