The lighthouses of Puerto Rico are the product of a master plan prepared by the government in response to the needs of maritime trade, which during the 19th century was the only way to import and export products, and the main route for transporting goods from one place to another on the island. The requirements of the plan, the dominant architectural style in Puerto Rico, and the economy of the era are clearly reflected in the location, style, size, and functionality of these buildings. Several elements common to all our lighthouses are presented here in order to provide a unified view and to avoid repetition in the text corresponding to each structure.

    The main criterion used for choosing the location of the lighthouses was the need to illuminate specific areas of the coast so that any ship approaching the island would always have one or more lights to guide it on its way to other countries, or in navigating to one of the local ports. For this reason many of the lighthouses were built in remote locations, some still difficult to reach, such as the Caja de Muertos, Culebrita, and Mona lighthouses. Remoteness, the need to manually operate the lights (electricity had not yet been invented), and the preference for integrating the tower and the keepers’ residence in a single building explains why the lighthouses are not isolated towers but rather homes equipped to meet all the needs of the families of that era.

    The architecture of our lighthouses is Neoclassic, a style dominated by simple but elegant straight lines. Only the Guanica and Rincon lighthouses deviated notably from this style, since they had complex brick cornices and parapets that reveal some Moorish influence. The San Juan lighthouse also has a Moorish touch which was repeated in the Ceiba lighthouse.

    Our lighthouses can be separated into two groups with respect to their size and importance. Large or primary lighthouses, like those at Cabo Rojo, Maunabo, and Fajardo were built for two keepers and their families. Typically, the building has one door, a central corridor leading to the tower, and identical living spaces on both sides of the corridor. The main function of these lighthouses was to illuminate strategic points along the coast, and since the light had to be visible from afar, they were equipped with second, third or fourth-order lenses. Small or secondary lighthouses, like those at Arroyo, Ponce and Vieques, were designed for one keeper and his family. These lighthouses, which illuminated ports and areas reached marginally by the larger lighthouses, were equipped with fifth or sixth-order lenses.

    All the lighthouses had a cistern for storing rainwater collected on the roof. The roofs were constructed of balata wood beams and trellises which generally supported several layers of bricks joined by a sand and lime mortar, the top layer of bricks was covered with tar or pitch to reduce filtrations. The inner layer of bricks was covered by a lime wash and the beams and trellises were painted to protect them from moisture. Walls were built of brick and stone, while external doors and shutters were made of capá or other local woods. At a minimum, the floor of the lobby, the main corridor, and the base of the tower were covered in marble (Genoa slabs). The floor of the keepers’ quarters were covered with pine wood, while that of work areas, fuel deposit, and kitchen were made of cement. The large lighthouses had modern kitchens and toilets, while the small ones had wood-burning stoves and latrines.

    The lighthouse tower is cylindrical, hexagonal or octagonal and may be at the center of the building or attached to the rear facade. The most notable element of its interior is the spiral iron staircase, imported from France, that leads to the building’s roof and then to the lantern. The tower’s height depends on the terrain’s elevation and the power of the lens: lights located at sea level require higher towers than those built on promontories, while primary lighthouses have to project their light from a higher point so as to reach further. The towers of the local lighthouses are short  when compared to those of most Spanish lighthouses built in Cuba and the Philippines.

    The lantern is the metal and glass structure crowning the tower. All the lanterns of the Spanish lighthouses, complete with their lamps and lenses, were purchased in Paris, where several companies specialized in lighthouse equipment operated. The lantern was surrounded by a decorative iron balustrade that protected the keepers when they cleaned the exterior. The roof of the lantern has a ball with ventilation holes, followed by indicators of the cardinal points, a vane to indicate wind direction, and a platinum-tipped lightning rod. A steel-wire cable descended from the rod to the ground. In the center of the lantern was the lamp, surrounded by the lens. The lamps burned fuel imported from New York, where a specific variety called bright light was distilled for use in lighthouses. The fuel was stored in an oil room, which in some lighthouses is below the tower. Whale oil was not used as fuel in Puerto Rico.

    The lighthouses were equipped with Fresnel lenses, named in honor of French physicist Augustine-Jean Fresnel (1788-1827). The size of the lens and the number of prisms are proportional to its power and range. First-order lenses have a range of 24 miles, are formed by over a hundred lenses and prisms, are about 10 feet tall and weigh over a ton. At the other extreme, sixth-order lenses have a range of eight miles, are about 2 feet tall, have about a dozen lenses and prisms, and are relatively light. The most powerful lens used in Puerto Rico was the second-order optic of the Mona lighthouse. The other primary lighthouses used third or fourth-order lenses, while the secondary lighthouses used fifth or sixth-order lenses. The only lighthouses that retain their original lenses are those at Maunabo and San Juan, all others have beacons installed later. The Coast Guard has a small museum in San Juan where several lenses are exhibited, including the original lens of the Ponce lighthouse.

    Fifth and sixth-order lenses were fixed but the others were mounted on a base that rotated around the lamp. The shape of the lens and the rotational speed produced a flashing pattern specific for each  lighthouse, thus allowing its identification from afar. The force needed to rotate the lens was provided by a clock mechanism driven by weights which in most of lighthouses descended through the stairway’s column. When the weights reached the bottom, which could happen in just two hours, the keeper had to climb to the lantern and turn a lever to raise them. During the day a curtain protected the lamp from the sun’s concentrated rays.

    During the first decades of the last century electrification of the lighthouses started, first through  generators and then through power lines. The oil lamps were replaced by light bulbs and the clock mechanisms by electric motors. With the lights automated, resident personnel was no longer necessary and the structures began to be closed, abandoned, and inevitably deteriorated. The classic era of the lighthouses reached its end. After half a century or more of neglect, interest for the lighthouses has revived and several have been beautifully restored. Slowly they return to life and begin a second era, where as tourist attractions and as part of our cultural heritage they are witnesses of a very special past.

One of several maps illustrating the maritime illumination plan. This undated version includes the Desecheo and Mayagüez lighthouses, which were not built and does not include Vieques’ Puerto Ferro lighthouse.