Lights, Shapes, and Sounds

• Introduction
• Chapter 1 The Law of the Dark: Ancient Sea Customs and Night Navigation
• Chapter 2 Unregulated Waters: Early Collisions and Common Law Admiralty
• Chapter 3 The Trinity House Rules of 1840: Codifying the First Signals
• Chapter 4 Coal, Steam, and Iron: The Speeds That Demanded Lights
• Chapter 5 The British Steam Navigation Act: Legislating Lanterns
• Chapter 6 Port Red, Starboard Green: The Birth of Colored Running Lights
• Chapter 7 The Masthead Lamp: Defining Heading, Speed, and Range
• Chapter 8 Anchored in the Channel: The Evolution of Riding Lights
• Chapter 9 The Merchant Shipping Act of 1854: Expanding Statutory Duties
• Chapter 10 From Fog-Bells to Steam Whistles: The Acoustic Frontier
• Chapter 11 Blind in the Bank: Early Fog-Signals and Auditory Jurisprudence
• Chapter 12 The Anglo-French Accord of 1862: The First International Code
• Chapter 13 Spheres, Cones, and Drums: The Introduction of Day-Shapes
• Chapter 14 The Washington Conference of 1889: Standardizing Global Safety
• Chapter 15 Not Under Command: Signaling Distress and Disability
• Chapter 16 Vessels Constrained by Draft: The Legal Struggle Over Deep Hulls
• Chapter 17 Fishing Fleets and Trawlers: Competing Claims in the Dark
• Chapter 18 Maneuvering Whistles: One Blast to Port, Two to Starboard
• Chapter 19 The Danger Signal: Five Blasts and the Burden of Inattention
• Chapter 20 SOLAS 1914: The Titanic Disaster and Enhanced Signal Mandates
• Chapter 21 The Impact of Radar: Sight, Sound, and Blind Reliance
• Chapter 22 Drafting COLREGs 1972: A Unified Legal Framework
• Chapter 23 Modern Special Cases: Hovercraft, Hydrofoils, and Wing-in-Ground Craft
• Chapter 24 Liability and Apportionment: How Signal Failures Are Tried in Court
• Chapter 25 Unmanned Hulls and Digital Oceans: The Future of Maritime Signaling Law

On a moonless night in open water, the sea offers no horizons, no landmarks, and no natural warnings of impending disaster. For centuries of maritime enterprise, ships sailed blind through this liquid darkness, their captains relying on fortune, sharp lookouts, and the unwritten customs of the deep. When two wooden hulls tore into one another beneath a blanket of fog or amidst the black swell of the English Channel, the disaster was often attributed to an act of God or the unavoidable perils of the sea. Yet, as the industrial age replaced wood with iron and wind with steam, collisions ceased to be rare tragedies of the wilderness. Instead, they became a systemic, catastrophic crisis of speed and blind momentum. The ocean had not changed, but humanity had introduced machines capable of crushing one another in minutes, demanding a radical transformation in how mariners perceived each other across the waves.

The answer to this escalating peril was neither higher seawalls nor thicker hulls, but a quiet, rigorous revolution in communication. Over the course of two centuries, the international maritime community constructed a universal, non-verbal syntax designed to pierce fog, cut through darkness, and announce identity across miles of open ocean. Colored lanterns mounted on port and starboard rails, black canvas shapes hoisted into the rigging, and rhythmic blasts of steam whistles and fog-bells ceased to be optional safety precautions. They became codified legal imperatives. This book is the story of how lights, shapes, and sounds—simple sensory phenomena—were forged into the most successful, universally observed system of statutory behavior in global legal history: the International Regulations for Preventing Collisions at Sea (COLREGs).

To understand this transformation is to trace the intersection of technological disruption, admiralty jurisprudence, and international diplomacy. In the early nineteenth century, an illuminated candle hung over a bow was an idiosyncratic choice made by an anxious master; by the end of the Victorian era, the omission of a ten-point green light was prima facie evidence of statutory fault before an admiralty judge. The path between those two points was fraught with trial, error, and immense loss of life. It required the pioneering intervention of Britain’s Trinity House, the legislative muscle of the Merchant Shipping Acts, the bilateral cooperation of the Anglo-French Accord of 1862, and the landmark international assembly at the Washington Conference of 1889. Each mandate—the arc of visibility of a masthead light, the precise geometry of a black ball signifying a vessel at anchor, the five rapid blasts of a whistle signaling acute doubt—was paid for in wreckage and hammered out in maritime courtrooms.

Yet Lights, Shapes, and Sounds is not merely an engineering manual or a technical digest of navigational equipment; it is a legal history of perception and liability. Long before radio, satellite transponders, or digital networks, the law demanded that a watch officer interpret an abstract language of photons and sound waves and make split-second determinations that carried severe legal and mortal consequences. When two vessels converged, the legal duty of each master was dictated entirely by what could be seen or heard: a solitary white lamp meant an overtaking vessel or a vessel at anchor; a red light crossing from left to right meant a give-way obligation under the force of law; three black shapes in a vertical line declared a ship not under command, altering the legal rights of every hull within sight. Maritime courts in London, Paris, and Washington had to develop an entirely new body of jurisprudence to apportion blame when lights failed, horns were muffled by atmospheric acoustics, or lookouts misread the silent geometry of the night.

The relevance of this history has never been sharper. Even in an era dominated by automated radar plotting aids, Electronic Chart Display and Information Systems (ECDIS), and satellite-linked Automatic Identification Systems (AIS), the primary legal instruments of collision avoidance remain anchored in sensory signaling. Courts across the globe still hold fast to the fundamental principle that electronic screens do not relieve a mariner from maintaining a proper lookout by sight and hearing. Furthermore, as the maritime sector stands on the precipice of its next great transformation—the deployment of autonomous, unmanned surface vessels—the ancient grammar of lanterns, day-shapes, and acoustic blasts faces its most profound test. How an artificial intelligence processes a cone hoisted point-downwards, or how an unmanned hull communicates its legal status to a passing trawler, forces us back to the foundational questions that confronted the steamship pioneers of the 1840s.

This book invites readers into the wheelhouses, shipyards, and admiralty courtrooms where the modern law of the sea was forged. It explores how engineers calculated the visibility of whale-oil lamps, how jurists grappled with the deceptive acoustics of fog banks, and how sovereign nations surrendered pieces of their domestic prerogatives to establish a single, unbreakable code for all who navigate the water. By examining the legal architecture of these signals, we uncover not only the mechanics of marine navigation, but a profound testament to international law itself: an enduring, elegant framework built to ensure that amid the isolation of the sea, no vessel travels entirely alone or entirely in the dark.

For the greater part of human history, taking a vessel out upon the water after sunset was regarded as an invitation to catastrophe, if not an act of outright madness. Mediterranean sailors of antiquity—Phoenicians, Greeks, and Romans alike—practiced what was essentially an amphibious form of coasting. They hugged the shoreline, watched the flight of migrating birds, tracked the jagged contours of headlands, and, whenever the purple shadows of evening began to stretch across the Aegean or the Tyrrhenian, promptly dragged their keels up onto the nearest shingle. Night was not merely an inconvenience; it was an existential void. Without the sun to fix a bearing, without coastal landmarks to warn of shoals, and without the slightest artificial illumination to reveal another ship plunging through the swells, the open sea after dusk was regarded less as a highway and more as a vast, unlit grave.

When merchants and commanders did find themselves caught offshore beneath an overcast night sky, they had no governing framework for avoiding one another beyond panic and prayer. There were no lights mounted to the bows of an Athenian trireme or a Roman corbita. The concept of affixing an open flame to a hull constructed of dried wood, sealed with flammable pine pitch, and packed with dry cordage was universally understood to be far more dangerous than the remote chance of striking another hull in the dark. Fire was the sailor’s most terrifying enemy, far outstripping the menace of unseen timber in the night. To carry an exposed brazier or a smoking tallow torch along the bulwarks while rolling in a cross-swell was to invite instantaneous immolation. Consequently, ancient mariners navigated the night wrapped in total, deliberate blackness, listening intently for the roar of breakers or the frantic shouts of another crew drifting helplessly down the wind.

The earliest surviving legal compilations reflect this maritime terror, yet they are strikingly silent on the mechanics of night signaling. The celebrated Lex Rhodia—the Rhodian Sea Law, whose fragments were preserved within Byzantine codifications such as the Digest of Justinian and later the Nomos Rhodion Nautikos—devoted meticulous attention to the economics of disaster. It established elaborate formulas for general average, dictating who should pay when cargo was jettisoned to save a wallowing hull, who owned the salvage hauled from the seabed, and what penalties awaited a helmsman who ran a ship aground while drunk. Yet it offered virtually nothing on how two vessels meeting in the pitch-black Mediterranean should conduct themselves, let alone how they ought to announce their presence. The law assumed that if two ships collided in the dark without deliberate malice, the incident was simply an unavoidable misfortune—a stroke of vis major, or an act of God. The sea was an inherently dangerous arena, and the state did not presume to tell the master of a merchantman how to display a lantern he did not possess.

The physical reality of ancient navigation made complex rules of the road almost irrelevant. Vessels were slow, heavily dependent on seasonal winds, and rarely traveled in dense formations outside of military expeditions. A Roman grain ship lumbering between Alexandria and Ostia moved at the whim of the Etesian winds, its massive square sail offering negligible maneuverability to windward. If two such leviathans encountered one another in a squall at two o’clock in the morning, their rudders—large steering oars lashed to the quarters—were rarely nimble enough to execute a sudden avoidance maneuver, even had the lookouts spotted the opposing canvas in time. When collisions occurred in the ancient world, they were almost exclusively harbor accidents, occurring where vessels were crammed into tight anchorages, or disastrous strandings where a ship parted its cables and drifted into its neighbors.

In these crowded anchorages, the first recognizable ancestor of maritime traffic management began to emerge, though it relied on stationery sentinels rather than moving lights. The great Pharos of Alexandria, burning wood and perhaps bituminous coal at the entrance to Ptolemaic Egypt’s premier port, was designed to mark the threshold between the chaos of the open sea and the safety of the harbor. Similar towers at Ostia, Ravenna, and Dover cast a smoky, flickering beam over dangerous headlands and narrow channels. But these grand structures were fixed geographic warnings, not interactive navigational dialogues. They informed the mariner where the land ended, but they did nothing to tell him whether another ship was bearing down on his larboard quarter.

To the extent that lights were employed at sea at all during antiquity and the early Middle Ages, they served a strictly vertical, hierarchical purpose rather than a lateral, communicative one. In naval warfare, an admiral’s flagship—the vessel that held the commander, the treasure, and the tactical plan—would occasionally display a large lantern, or fanal, hoisted high upon its stern pooped deck. This was not a warning beacon to prevent merchant ships from blundering into the fleet; it was an organizational tether. In the Strategikon of Maurice, a sixth-century military manual from Byzantium, and in later Venetian fleet orders, we find directives instructing subordinate captains to keep their eyes fixed upon the lantern of the commanding galley. If the admiral tacked, the fleet tacked; if the admiral anchored, the trailing ships let go their iron. The light was an emblem of command and cohesion, an imperative of obedience. It was certainly not an instrument of public safety, and outside of fleet operations, displaying such a light was generally considered a foolish invitation to pirates, wreckers, and corsairs who patrolled the Mediterranean littoral.

As maritime trade revived in Western Europe during the high Middle Ages, the center of maritime legal gravity shifted northward toward the Atlantic coast, the English Channel, and the Baltic Sea. Here, sailors encountered an entirely different oceanic environment: tides that rose and fell dozens of feet twice a day, perpetual gray mists, fierce westerly gales, and long winter nights that lasted sixteen hours. In these treacherous, hyper-active waters, merchant syndicates and seafaring communes began to record regional compilations of maritime custom. Chief among these were the Rôles d'Oléron, traditionally attributed to the influence of Eleanor of Aquitaine in the late twelfth century, which circulated across northern Europe and became the foundational text for the English High Court of Admiralty.

The Rôles d'Oléron are famous for their salty pragmatism and ruthless common sense. They settle disputes between masters and mutinous crews, lay out the duties of pilots, and address what must happen if a crewman falls sick while on a voyage to Bordeaux to load casks of wine. Article 14 of the Rôles addresses the subject of collisions with startling clarity, though it reveals just how primitive collision doctrine remained. The rule deals with the common scenario of an anchored vessel being struck by a ship entering a harbor or harbor-reach under sail. If the moving vessel collided with the anchored vessel and caused damage, the rule dictated that the total cost of the damage to both ships was to be added together and divided equally between the two parties—provided the master and mariners of the striking ship swore an oath upon the Holy Gospels that the collision was accidental and not malicious.

The logic behind this half-and-half apportionment was remarkably cynical, reflecting the suspicious nature of medieval coastal commerce. The ancient scribes of Oléron noted that if the striking ship had to bear the full cost of the accident, an unscrupulous master whose own ship was aging, rotted, and barely seaworthy might deliberately run down an opulent, well-appointed vessel at anchor simply to claim that the other ship was somehow at fault, or to seek an excuse to abandon his own decaying hulk. By splitting the loss down the middle, the law removed any commercial incentive to ram another craft.

Yet conspicuously absent from the Rôles d'Oléron is any mention of a legal requirement to hang a lantern while riding at anchor in a dark fairway. A vessel anchored in a tidal river like the Garonne or the Thames was under no statutory duty to illuminate its position. The onus fell entirely upon the vessel under sail to exercise extreme caution, to feel its way through the dark with the sounding lead, and to post sharp-eyed men in the bow. If a sailor could see nothing through the black drizzle, he was expected to drop his own anchor and wait for daybreak. The law of Oléron accepted darkness as an immutable condition of nature, an absolute constraint under which mariners proceeded strictly at their own peril.

In the Baltic and North Seas, the great commercial network of the Hanseatic League produced its own legal codes, known collectively as the Wisby Town-Law on Shipping and the Hanseatic Ordinances. The Hanseatic merchants were terrified of collisions, not merely because ships and timber were expensive, but because the waters of the Kattegat and the Skagerrak were notoriously confined, rocky, and choked with sea ice. The Hanseatic statutes expanded upon the Oléron principles, retaining the equal division of damages for accidental collisions and establishing stiff financial penalties for negligence.

Still, neither the Hanseatic merchants nor the authors of the Mediterranean’s sweeping Consolat de Mar—the fourteenth-century Consular Code of Barcelona—mandated running lights for vessels on the high seas. In the vast corpus of the Consolat, which spans hundreds of chapters regulating everything from the rations of deckhands to the legal power of a master to sell the ship’s rigging in an emergency, the sea at night remains an unlit theater. The Mediterranean sailors who answered to the Consolat were navigating lateen-rigged galleys and stout round ships called cochas. They were acutely aware of other vessels, but they communicated by shouting, blowing conch shells or brass horns in coastal fogs, and, above all, by relying on the dark adaptation of their own eyes.

The biological reality of human vision was, in truth, the only regulatory code that operated consistently across ancient and medieval waters. Lookouts were trained from boyhood to distinguish the faint outline of white canvas against black water, or to detect the phosphorescent wake thrown up by an approaching prow. To introduce a small, flickering tallow candle or an open oil dish on one’s own vessel was frequently viewed as a handicap rather than a help: it completely destroyed the night vision of the lookout stationed nearby, casting an impenetrable glare onto the ship’s own gear and blinding the watch to the silhouettes of distant reefs and ships. A lantern illuminated the ship that carried it, but it blinded the men tasked with seeing beyond it.

There were, however, rare exceptions where the law did begin to compel illumination, but these were born of tactical self-defense rather than traffic regulation. As long-distance voyaging expanded toward the end of the fifteenth century, convoys became the dominant mode of international commerce. When Spanish fleets, the Flota de Indias, began carrying silver across the Atlantic from Veracruz to Seville, and Portuguese naus ventured around the Cape of Good Hope on the Carreira da Índia, traveling in tight groups was the only defense against English privateers, French corsairs, and Dutch raiders.

Within these massive, lumbering armadas, strict naval discipline imposed signaling systems that would eventually bleed into commercial practice. The Capitana, the commanding flagship, and the Almiranta, the second-in-command that brought up the rear of the fleet, were required by royal decree to display large, glazed stern lanterns. These lanterns, often magnificent constructions of brass, copper, and horn panes, burned thick wicks soaked in olive oil, whale oil, or rendered beef tallow. The royal instructions issued by the Spanish Casa de la Contratación were unforgiving: if an ordinary merchant vessel lost sight of the flagship’s light during the night and drifted separated from the convoy, its master faced ruinous fines, loss of his commercial license, or even a sentence to the royal galleys for dereliction of duty.

These convoy lights served as homing beacons. In dense weather or total darkness, the flagship would supplement its stern light with auditory signals: a single discharge of a culverin or an arquebus meant the fleet should anchor; two shots meant tack into the wind; three shots meant shorten sail. If a trailing ship observed a sudden squall bearing down, it was instructed to burn a "false fire"—a handful of loose gunpowder ignited in an iron skillet along the deck—to warn the ships astern. These pyrotechnic displays were bright, sudden, and terrifyingly vivid, but they were emergency signals, used sparingly and with tremendous caution to avoid igniting the ship’s own sails.

Outside of these highly militarized, strictly governed convoys, the ordinary free-trading merchantman continued to sail through the night in absolute obscurity. The seventeenth-century sea was an anarchic space. Under the emerging principles of international law articulated by jurists like Hugo Grotius in his 1609 tract Mare Liberum, the high seas were the common property of all mankind, incapable of being appropriated by any sovereign. While this doctrine liberated oceanic commerce from Portuguese and Spanish monopolies, it also created a profound jurisdictional vacuum. No single king, parliament, or maritime court possessed the authority to tell a Dutch fluyt, an English brig, and a French chausse-marée what equipment they had to lash to their masts while traversing the open Atlantic.

Even in coastal waters, where national jurisdiction was claimed under the competing doctrine of Mare Clausum advanced by English scholars like John Selden, the common law and early admiralty courts were intensely reluctant to penalize a shipowner for failing to show a light. If an English collier hauling sea-coal from Newcastle to the Thames struck a becalmed ketch off the Norfolk coast on a pitch-black October night, the resulting litigation in the High Court of Admiralty turned almost exclusively on seamanship and customary craft knowledge, not on the violation of statutory regulations.

The judges who sat in Doctors’ Commons in London, assisted by senior sea captains acting as nautical assessors, asked very specific questions of the surviving witnesses. Did the vessel maintain a sufficient lookout on the forecastle? Were the sails trimmed appropriately for the wind and sea? Did the helmsman respond instantly to the hail of the watch? Was there an unseamanlike delay in letting go the halyards or putting the helm down? If both crews had fulfilled their traditional, unwritten maritime duties according to the ordinary custom of the sea, the collision was ruled to be "inevitable accident." Each party was sent away to repair its own timbers and mourn its own drowned hands, with the court observing that the darkness had simply triumphed over human vigilance.

This customary maritime jurisprudence rested entirely upon unwritten rules that relied on daylight sight lines. By day, seasoned mariners obeyed several intuitive rules of thumb that had crystallized over centuries of working with canvas and wind. A vessel sailing close-hauled—pinching as close to the wind as its sails would allow—was acknowledged to have far less freedom of movement than a vessel sailing with the wind free, running easily before the breeze. It was universally accepted as a matter of common-sense honor and self-preservation that the vessel with the wind free had a duty to maneuver out of the way of the vessel pinned down close to the wind. Similarly, if two sailing vessels were both close-hauled and beating into the wind on opposite tacks, the vessel on the port tack (receiving the wind over its left side) was traditionally expected to give way to the vessel on the starboard tack (receiving the wind over its right side).

These daylight customs worked reasonably well because an experienced lookout, viewing another ship under a clear sky, could instantly calculate the other ship’s heading, its angle of heel, the trim of its sails, and its physical relationship to the prevailing wind. The look of the canvas, the froth under the cutwater, and the tilt of the spars told an unmistakable story to an experienced eye. A captain standing on the quarterdeck did not need to guess whether the approaching ship had the wind free; he could see the billowing square sails and the slackened sheets.

At night, however, that entire visual grammar disintegrated. In the dark, a captain could not see the angle of the other ship’s yards. He could not determine whether the mysterious shadow looming out of the blackness had the wind on its larboard or starboard side. He could not tell if the ship was bowling along at eight knots or wallowing dead in the water, caught in stays with its sails aback. All that appeared to the terrified lookout was a towering mass of black canvas emerging from the night, fifty yards away and closing fast. By the time a master could bellow down the companionway to summon the watch below, the bowsprit of the stranger was already grinding through the bulwarks, splintering oak ribs, snapping shrouds like violin strings, and sending sleeping men into the sea.

The technological limitations of the era’s lighting only deepened the dilemma. Even if a conscientious captain desired to illuminate his ship, the available technology was woefully inadequate. Prior to the late eighteenth century, the primary sources of portable light were candles made of mutton tallow, which guttered, smoked, and extinguished themselves in the slightest sea breeze, or rudimentary iron lamps burning crude fish oils that emitted a murky, foul-smelling glimmer barely visible past the bowsprit. Glass was expensive, fragile, and prone to shattering under the thermal shock of cold sea spray hitting a heated pane. Horn lanterns, which used scraped, semi-translucent animal horn instead of glass, were durable enough to survive a tossing deck, but they shed only a dull, yellow, diffused aura that could not penetrate more than a few ship-lengths through damp oceanic air.

To make matters worse, keeping a flame alive required tending. A lamp left untended in the bows was likely to smoke its horn panes with thick soot within an hour, reducing its already pathetic candlepower to near-invisibility. In heavy weather, when spray broke clean over the forecastle, keeping an oil lamp lit was an exercise in futility. It required an assigned deckhand whose sole task was to shelter, trim, and scrape the lamp—a luxury of manpower that few commercial merchantmen, operating on razor-thin profit margins with skeleton crews, were willing to afford.

Consequently, night navigation remained an exercise in stealth and silent vigilance well into the dawn of the Industrial Revolution. Ships drifted past one another in coastal waters like gray phantoms. A master might burn a lantern on the quarterdeck for a brief moment while consulting a paper chart or reading the compass in the binnacle, but the light was carefully shielded with wooden hoods or canvas screens to protect the helmsman’s eyes from night-blindness. In the English Channel, along the treacherous approaches to Ushant, and across the shoals of the North Sea, thousands of tons of cargo and thousands of human lives traversed the midnight waters in total darkness, relying entirely on the keen ears of the watch, the scent of land, the sounding of the lead line, and the uncertain mercy of the elements.

This status quo was not the result of legislative apathy or criminal indifference. It was the product of a world in which the speed of transit was fundamentally constrained by the natural forces of wind and tide. When sailing ships collided in the seventeenth and eighteenth centuries, their closing speeds were almost always modest. Unless caught in a ferocious gale, two merchantmen meeting bow-to-bow were rarely closing at more than five or six knots. Even in the dark, the human voice could carry across water; a frantic hail of "Luff! Hard down your helm!" through a speaking trumpet was often heard just in time to avert a catastrophic direct impact, resulting instead in a glancing blow, torn rigging, and entangled spars that could be cut away with axes.

The sea, for all its dangers, was also vast, and the volume of commercial traffic, by modern standards, was exceptionally light. A merchantman might spend weeks crossing the Atlantic without ever raising another sail upon the horizon, day or night. In such an environment, the statistical probability of two tiny wooden hulls occupying the exact same point of the surface of the globe at the exact same minute in the dark was remarkably low.

Yet this fragile equilibrium, which had governed maritime life since the dawn of navigation, was already beginning to fracture as the eighteenth century gave way to the nineteenth. The explosive growth of global trade, the colonization of distant continents, and the relentless rise of coastal commerce were steadily filling the traditional choke points of European shipping with unprecedented numbers of vessels. The English Channel, the Kattegat, the mouth of the Scheldt, and the approaches to Liverpool and New York were rapidly transforming from lonely wildernesses into crowded maritime corridors.

As the volume of traffic mounted, the ancient custom of navigating in the dark was shifting from an accepted, unavoidable condition of life at sea into a deadly liability. The law, bound by centuries of precedent that treated collisions as acts of God or shared misfortunes without fault, was entirely unprepared for the sheer volume of tonnage soon to be driven through the dark. Before the legal architects of the maritime world could construct a systematic, statutory code of lights, shapes, and sounds, they first had to reckon with the failures of the ancient customary law—and the mounting wreckage that was beginning to litter the common law admiralty courts of the Western world.