In 1831, the House of Commons Select Committee on Steam Navigation recommended that two steam vessels meeting unexpectedly head-on should both put their helms a-starboard. The recommendation was not adopted. Five years later, the Royal Commissioners on Pilotage reported frequent collisions between steam vessels, the absence of defined rules and the failure to act on the earlier proposals. Noting that “the evil continues to increase”, they appended a proposed rule of the road.

The Admiralty issued passing rules for steam warships in 1839. These prescribed passing to port, contrary to the common practice of passing to starboard.

On 30 October 1840, Trinity House in London promulgated two provisions for steam vessels. When vessels on crossing courses had to pass close to one another, each was to put her helm to port and pass on the larboard side of the other. A steam vessel passing another in a narrow channel was likewise to leave that vessel on her larboard hand. Both provisions concerned steering; neither prescribed lights.

Parliament incorporated the provisions into the Act for the Regulation of Steam Navigation of 28 August 1846. An amending act followed in 1851, and the Merchant Shipping Act followed on 10 August 1854.

The Trinity House rule of 1840 is sometimes described as the first lighting regulation. It was a rule of the road for steamers, subsequently given statutory force, rather than a requirement governing their lamps.

The Admiralty notice of 11 July 1848 is where the navigation light as it is now known begins.

An Admiralty committee reported on the lights of steam and sailing vessels on 29 March 1857. Its report, published in full in The Nautical Magazine that year, followed the work of a committee in 1856. A central question was whether a sailing vessel's lights should indicate her tack or remain assigned to a particular side.

The committee recommended a fixed arrangement: red to port and green to starboard, as on a steamer. The patterns circulated with the report included a model sidelight and a model anchor light. Lanterns were to be kept ready on their respective sides of the vessel, a recommendation connected with the painting requirements discussed in Painted Ship's Lamps.

The report formed part of the background to the British order of 24 February 1858 and the French decree of 28 May 1858. These national measures preceded the international rules of 1863.

Read the Admiralty committee report, 29 March 1857. 

L. Sautter & Cie reproduced the French decree in their 1858 catalogue, placing the legal requirements alongside the lanterns offered to meet them. Signed at Fontainebleau by Napoleon III and Admiral Hamelin, minister of the navy and colonies, the decree came into force on 1 October 1858.

Lights Under Way

Steamers under steam were required to carry a white light at the foremast head, showing over an arc of 225 degrees. On either side, this extended from directly ahead to two points abaft the beam. The green starboard light and red port light each covered 112 degrees 30 minutes.

Each sidelight had an inboard screen running fore and aft and projecting 0.90 metres ahead of the light. The screens prevented the green light from being seen from the port side of the bow, and the red light from the starboard side. Sailing vessels and steamers with their engines stopped carried the same sidelights, but not the white foremast light.

Pilot Boats and Vessels at Anchor

Sailing pilot boats carried a permanent white all-round light at the main masthead. A second white all-round light was hoisted every quarter of an hour and displayed briefly.

A vessel anchored in a roadstead, channel or frequented route carried a white all-round light. It had to be placed where it could best be seen, but no more than six metres above the gunwale.

Visibility and Fog Signals

On a dark night without fog, the white foremast light had to be visible at five nautical miles, the sidelights at two miles and the anchor light at one mile. Fog signals were required at intervals of five minutes or less.

Steamers used a steam whistle forward of the funnel and at least 2.40 metres above the deck. Sailing vessels used a horn on the starboard tack and a bell on the port tack. Article 7, concerning portable lanterns for small sailing craft, is discussed in Painted Ship's Lamps.

Regulation lanterns and their prices in L. Sautter & Cie's Phares et fanaux lenticulaires, Paris, 1858. The catalogue reproduces the decree that the lanterns were intended to satisfy. Gallica / Bibliothèque nationale de France.

Read the French decree of 28 May 1858.

The Order in Council made at Osborne House on 9 January 1863 brought steering and lighting requirements together in one body of regulations. The British Board of Trade prepared the rules in cooperation with the French government. More than thirty countries adopted the system, including Germany and the United States, while Spain legislated in the same year. In 1864, President Abraham Lincoln signed the Rules to Prevent Collisions at Sea into United States law.

For the collector, Article 7 provides a useful physical specification. It required an anchor light in a globular lantern eight inches in diameter, visible all round at a distance of at least one mile. The lantern was to be carried no more than twenty feet above the hull.

Successive revisions introduced more detailed requirements for particular vessels and activities. Fishing, towing, cable work and overtaking each required lights that could be recognised at night.

The sternlight developed more gradually than the sidelights. In 1879, an overtaken vessel was required to show a white light or a flare-up to the vessel approaching from astern; this did not yet amount to a permanent sternlight.

A fixed sternlight became compulsory for almost all vessels under way in the 1948 rules. Even then, a small vessel unable to mount one could keep an electric torch or a lighted lantern ready to show in sufficient time.

Twentieth-century revisions retained much of the earlier lighting system while changing its dimensions, ranges and application to different sizes of vessel. Adoption and entry into force were separate events.

The interval matters when dating a lantern. A regulation's adoption date does not, by itself, establish when a lamp built to its requirements entered service.

The 1948 Rules

The 1948 text retained compass points and English feet. Power-driven vessels of 150 feet, approximately 45.7 metres, and over had to carry a second masthead light. A fixed sternlight became compulsory for almost all vessels under way.

The rules also specified the positions of the lights. The two masthead lights had to be at least fifteen feet apart vertically, with a horizontal separation of at least three times that distance. The lower light was placed forward. Sidelight screens had to project at least three feet.

The 1960 Rules

The 1960 regulations largely retained the 1948 requirements, including their visibility ranges and the 150-foot threshold for anchor-light arrangements. They introduced concessions for small craft at two additional length thresholds: sixty-five feet and forty feet.

The 1972 Rules

The 1972 regulations replaced compass points and feet with degrees and metres. The threshold for a second masthead light changed from 150 feet to fifty metres.

Required visibility ranges also increased. A masthead light on a vessel of fifty metres or more had to be visible at six nautical miles rather than five, and sidelights at three miles rather than two. Vessels under twenty metres could combine their sidelights in a single lantern on the centreline, the arrangement described under Bicolour.

Transitional exemptions allowed existing vessels to retain certain older arrangements. These provisions are important when considering how long an old lantern might have remained in working service; they are discussed in From Oil to Electricity.

Nineteenth-century British, Spanish and French regulations expressed light sectors in points of the compass. One point equals 11.25 degrees.

The 1948 and 1960 rules gave both measurements, placing degrees in brackets after compass points. The 1972 rules used degrees alone.

Seaplanes were treated differently in the 1948 text. Their sectors were already expressed solely in degrees, at 220 and 110 degrees, while the provisions for ships still used compass points. Both systems therefore appeared in the same document.

In the first half of the nineteenth century, red and green were not consistently assigned to particular sides. The British Admiralty decided in 1847 that starboard should be green and port red. Several European countries adopted this arrangement in 1858, and it was retained in the international regulations of 1889.

Two explanations for the choice circulate among collectors and seafarers. One connects green with the starboard steering oar: a helmsman could more readily see an approaching vessel on that side, supposedly making it the safer side. The other associates red to port with the position of the heart on the left of the body. Neither explanation is documented in the regulations.

The practical reason for standardisation is clearer. Once each colour consistently indicated one side, a vessel's lights could help another vessel determine her heading at night. Agreement on the arrangement was essential, whatever the original reason for choosing the colours.

The collision regulations consulted for these pages, from 1848 through 1972, define lights by their sectors, positions and visibility ranges rather than by prescribing a particular fuel or power supply. An oil lamp could therefore remain in service after electric lighting had become common, provided it continued to meet the applicable requirements. The use of paraffin and the transition to electricity are discussed in From Oil to Electricity.

These texts do not prescribe a manufacturer's mark either. National inspection and approval systems developed alongside the collision regulations, accounting for the different marks found on surviving lanterns. See Identifying a Ship's Lamp.

Early aviation rules borrowed from maritime practice. Sweden's air-navigation rules of 8 December 1922, effective from 1 January 1923, were reported to the Royal Swedish Society of Naval Sciences as broadly corresponding to the steering and lighting rules used at sea, with additions suited to aviation. Their order was also familiar: lanterns and signals first, followed by steering rules.

An aircraft manoeuvring on the water under its own power was subject to the maritime rules themselves. An aircraft anchored or moored on the water had to carry lights like an anchored vessel. Aircraft with a span of fifty metres or more also carried a white all-round lantern at each lower wingtip.

These requirements help explain the use of ordinary ship's anchor lanterns by seaplane stations and flying-boat operators. An aviation provenance need not mean that a lantern was designed specifically for aircraft.

Primary: London Gazette, 11 July 1848; decree on the lighting of ships, France, 28 May 1858, text in L. Sautter & Cie, Phares et fanaux lenticulaires, Paris 1858; Orders in Council of 9 January 1863, 30 July 1868, 14 August 1879, 11 August 1884 and 27 November 1896; Washington Conference recommendations, 1889; US Proclamation 368, 13 July 1894; United States federal ship lighting regulations, 1910; Regulations for Preventing Collisions at Sea, 10 June 1948; International Regulations, 1960 and 1972; The Nautical Magazine, 1857; Tidskrift i Sjöväsendet, 1923, no. 4.

Secondary: J.F. Kemp, Factors in the Prevention of Collisions at Sea, 1973, appendix II, which reproduces the regulations in full; R. Bahr, MPhil thesis, University of St Andrews, 1998; A.N. Cockcroft and J.N.F. Lameijer, A Guide to the Collision Avoidance Rules; M.T. Galindo Guil, on the Spanish regulation of 1863; Office of the Historian, US Department of State, for the committee report of 1876.