The Yard Transformed
It was not a dramatic launch—no gathering speed down the shipways and plunging into Boston Harbor. Instead, the water flowing into Dry Dock 1 rose slowly around U.S.S. MacDonough until the destroyer lifted off the keel blocks and was towed out of the dock. The 1934 “floating” was low-keyed but significant. MacDonough was the first warship built by Charlestown since the wooden screw sloop Vandalia slid down the ways in 1874.
The technological leap between the two vessels—partially bridged by the steel supply and fuel ships Charlestown built in the World War I period—was considerable. Except for its coal-fired auxiliary steam propulsion, the 216-foot Vandalia did not differ significantly from the old Constitution. MacDonough was a modern destroyer—the sloop-of-war’s 20th-century counterpart—incorporating the advances of the past 60 years. It was powered by geared turbines driven by steam generated in oil-burning boilers, and relied on sophisticated electrical, hydraulic, and communications systems. At 341 feet, its steel hull took up most of Dry Dock 1.
As soon as MacDonough was moved out of the dock, the destroyer Monaghan, just floated from Dry Dock 2, was moved into #1 for completion and outfitting. Two more keels were immediately laid in #2. It is noteworthy that neither dry dock was being used to repair ships. In fact, the whole yard’s traditional role as repair facility had given way in the past year to a new one as shipbuilder, a status it maintained through World War II. Charlestown built 12 destroyers in the 1930s and 24 more by the end of the war. Of course the yard built and serviced other types of vessels—especially destroyer escorts and LSTs (Landing Ship Tank)—but Charlestown acquired a reputation as a “destroyer yard” and thereafter specialized in this workhorse of the Navy.
Navy Yard Complex During World War II
This map of Boston Harbor in 1942 shows the five units of Charlestown Navy Yard during World War II. By war’s end the South Boston Annex was the largest, with dry docks big enough to repair battleships and heavy cruisers. The Chelsea and East Boston Annexes repaired small vessels, and the Fuel Depot Annex served the great number of naval vessels entering the harbor during the war.
CHELSEA Chelsea Naval Hospital Chelsea Naval Annex Fuel Depot Annex CHARLESTOWN Navy Yard EAST BOSTON East Boston Annex Pipeline DOWNTOWN BOSTON BOSTON HARBOR Deep Water Pier SOUTH BOSTON South Boston Annex
Ironically, the change had been brought about by the same economic crisis that almost put an end to the yard. After considering closing all yards but Norfolk and Philadelphia to save money, the Hoover administration in 1931 proposed closing only the Charlestown yard. Reaction was swift: committees were formed in Boston; petitions protesting the closing were signed. But it was probably the fact that MacDonough had been ordered a month earlier that tilted the scales in the yard’s favor. The keel was not laid for two years, however, and 1932 was the yard’s bleakest year since before the Spanish-American War, with only 1,500 people employed.
The Roosevelt administration’s program to stimulate the economy, provide jobs, and pull the nation out of the Depression was the first step in Charlestown’s transformation into a true ship construction yard. Under FDR’s 1933 National Industrial Recovery Act, 32 new warships were authorized, 20 of them destroyers, of which two were assigned to Charlestown. The following year, growing worries about Japanese aggression moved Congress to further expand the Navy.
The yard kept a rapid pace in the 1930s, laying two keels simultaneously in Dry Dock 2 in 1934 and again in 1935. (As the shipways was inadequate for destroyers, all keels were laid in this dock until 1939.) After floating, the hulls were moved into Dry Dock 1 for completion, the whole process taking about two years.
Repair work was much reduced in the 1930s by federal economy measures specifying lengthened maintenance intervals. As both dry docks were in any case usually tied up in construction work, and because most of the ships in for repair were relatively small, many of these vessels were floated into a large cradle and hauled from the water up the tracks of the yard’s marine railway. Others were taken across the harbor to the South Boston dry dock.
Technological change transformed many of the yard’s oldest trades by the 1930s, while the growing size and complexity of ships required more and more workers. Such large government employers as shipyards were seen by policy makers as places to both promote economic stability and save money. Early in the Depression these two goals were addressed, respectively, with lower and upper limits for each yard’s workforce—at Charlestown, 1,500 and 1,800. The workforce stayed generally within these limits until 1935, when it began growing, reaching some 5,000 workers by late 1939. (During hard times the yard kept its eye on the future, exempting apprentices from layoffs.)
By the time war had begun in Europe in 1939, with “readiness” again America’s watchword, the yard was operating at an even faster rate of production than in the mid-thirties. With the shipways enlarged to handle destroyers, six ships were in some stage of construction that summer. In October four destroyers were floated out of Dry Dock 2 on the same day. The yard also prepared 18 of the old World War I four-stacker destroyers for transfer to Britain under the 1940 destroyers-for-bases agreement.
Then came the war. If the thirties had been a period of gearing up, wartime pushed the yard into overdrive. It took a great war effort for the yard to realize its true shipbuilding and manufacturing potential, confirming a statement by Secretary of the Navy George von Meyer in 1910: “Navy yards are primarily for war and only incidentally for peace.” One historian’s conservative estimate: under the goad of war the yard built, repaired, overhauled, converted, or outfitted some 6,000 vessels between 1939 and 1945.
The raid on Pearl Harbor in December 1941 made every naval installation fearful of enemy attacks. Charlestown installed anti-aircraft batteries on roofs and camouflaged waterfront buildings. Some security measures were disruptive of yard routine. Blackouts and dim-outs were in force, especially in the early years of the war, to reduce the chances of ships being silhouetted against lights. When the air raid whistle blew, workers had to stop what they were doing and go to shelters. Throughout the war, yard officials juggled the conflicting demands of security and production.
Other security measures had more personal consequences. Some yard workers were banned from certain areas, and everyone was forbidden to speak foreign languages while at work. A number of workers were suspended in 1941 as security risks. “Remarks ... inimical to the government” were enough to earn an employee a place on the suspension list.
The huge number of people working at Charlestown was another sign that the yard had been remade by war. The U.S. Navy became the world’s largest single employer of industrial labor during the conflict, and the Charlestown yard held the same status in the Boston area. The yard’s force rapidly swelled from 5,000 workers in 1939 to a high of about 50,000 at Charlestown and its annexes in mid-1943, working around the clock in three eight-hour shifts.
As in World War I, the yard again had to protect its essential employees from the draft board. But voluntary enlistment proved to be the real drain on the workforce. Although yard foremen tried to dissuade crucial employees from going, some 13,000 workers left the yard to join the fight. Throughout the conflict, even when more than 50,000 people worked there, the yard was shorthanded.
Mainstays of the Yard: Warship Overhaul and Repair
After the construction boom created by World War II, Charlestown resumed its traditional role of “serving the fleet” (the yard’s motto). In the early 1950s it was the home yard for 121 vessels, including U.S.S. Cassin Young, the destroyer now on exhibit at the yard. All types of ships, but especially destroyers, came for everything from minor repairs to overhauls on established cycles. The latter, which often involved some degree of modernization, could require 800 to 900 workers a day. After the war the yard preserved decommissioned vessels of the Atlantic Reserve Fleet berthed at the South Boston Annex. Charlestown also prepared ships for transfer to allies, outfitted vessels built elsewhere, and repaired equipment, especially sonar.
Charlestown was busy in 1960 with overhauls and modernizations. In the foreground: aircraft carrier Wasp (whose crew presented the yard with the plaque shown above); floating dry dock (in a yard dry dock); heavy cruiser Macon (CA-132).
To make up for the shortages, the yard began for the first time hiring significant numbers of women and African Americans. Their door of opportunity, unlocked by the needs of a war economy, was kept open by pressure from civil rights groups on the Roosevelt administration (often relayed by a sympathetic Eleanor Roosevelt). Women at the yard had traditionally worked in clerical positions and as phone operators, and this remained true at war’s outset. But more and more women found work in the industrial shops, notably as welders and at the ropewalk (the latter having employed them during World War I). At least in some shops, however, there were restrictions. Gloria Brandenberg, who worked in the Paint Shop, recalled that all painter’s helpers were female, supervised by a woman (the “leading lady”), while all painters were male. Brandenberg said there was no chance for advancement.
By 1943 female blue-collar workers outnumbered women in clerical positions. Some 7,700 women were on the rolls in late 1944—far above their prewar level and about 19 percent of the workforce. Many worked as welders on ships under construction, but yard officials wary of contact between female workers and male crews barred women from all vessels in for repair. Painter’s helper Brandenberg recalled that the women were not allowed even to talk to sailors.
While African Americans were not officially excluded from Charlestown’s prewar workforce, few had been employed. When the war created opportunities for them, some whites openly resisted their presence in skilled positions. But this was not a universal attitude. Allan Crite, a black illustrator in the Design Department, said he experienced no racial problems. Inevitably, though, tensions arose in some areas. Gloria Brandenberg recalled an evening at a social club with her coworkers from the Paint Shop, one of whom was African American. She was asked to leave. The group talked it over; they all left. But the records show no major racial conflict at the yard. At war’s end more than 2,300 African Americans were in the force of 32,000 workers.
By late 1942, the yard had settled into a wartime routine—to the extent that routine is possible during war. Normal peacetime constraints didn’t apply. “During the war there wasn’t much emphasis on estimates,” recalled plumber Lyman Carlow. “For one thing, there wasn’t time. Here’s the job; we need the ship right away; get it done and whatever it costs it costs ... it was just a real frantic pace ... the material just flowed in ... plenty of people, so we could really get the work done.”
More than the higher level of general activity and the large numbers of workers (around 36,000 at this point), it was the volume of new construction that characterized the wartime yard. A walk around the yard on November 23 would have revealed ships being built in every facility but Dry Dock 2, used only for repairs.
Workers generally laid down and launched large vessels in pairs. But while floating two at a time out of a dry dock was standard practice, it was never approached casually. John Langan, a shipfitter during the war, recalled: “It was quite a feat, two destroyers right alongside each other, flooding the dock, and not having them crash.”
A new shipways built in early 1941 helped quicken the pace of production. In that year 10 destroyers were laid down, the most in any one year. By late 1941 the yard’s workers had pushed the time for building a destroyer down to a little over a year and would cut it to three or four months from keel to launching by the end of the war.
Women in the Workforce
“We all felt that we were doing our job, and the harder we worked, the faster we would get the ships out and the faster it would get over. Deep down, everyone was very serious about it, because ninety-nine out of a hundred people had a husband or a brother or somebody close to them that was overseas.” —Gloria Brandenberg, WW II Charlestown yard worker
Welders at Charlestown during World War II.
As enlistments and competition from private industry depleted the pool of male workers during World War II, the Navy looked to the large numbers of women who wanted to do their part for the war effort. Women had long worked at the Charlestown yard, although almost exclusively (except during World War I) in clerical positions. But beginning in 1942 the easing of state workweek restrictions for women hastened their recruitment into the yard’s manufacturing and traditional shipyard shops. The intention was to have them replace men in relatively unskilled positions requiring little training. And in fact most women did work as helpers in their shops, often with little chance of advancement. But some moved into the trades as machinists, riveters, painters, riggers, pipefitters, and especially as welders and ropewalk workers. At the same time women still occupied more than half of the yard’s clerical positions. Altogether, they made up about one-fifth of the yard workforce by 1945. Those in the trades knew their jobs would likely end when the war did, but the point had been made. In 1945, a yard historian wrote: “Experience over the past two years has proven that female employees are able to work efficiently on an equal basis with men on many jobs that were formerly considered to be men’s jobs.”
Welders at Charlestown during World War II.
The yard’s clerical workers enlisted as Yeomen-F (female) at the outbreak of World War I. Women also worked as radio operators and at the ropewalk.
Many responded to posters urging women to fill an industrial job and “free a man to fight.”
The new shipways was also used to build destroyer escorts (DEs)—smaller, slower, and less expensive versions of destroyers designed for escort duty and antisubmarine warfare. Escorted convoys had proven to be the only effective way to thwart U-boat “wolf packs” preying on allied shipping. In 1942, after the Navy ordered the first of more than a thousand DEs, Charlestown built a new dry dock in which it could turn out four at a time. The next year 50 DEs were laid down at the yard, half of which were destined for Britain in accordance with the Lend-Lease Act of 1941. Charlestown got the production of DEs down to an art: of the 62 it built, workers launched an impressive 46 in the first eleven months of 1943.
If 1941 was the year of the destroyer at the yard and 1943 belonged to the DE, 1944 was the year of the LST (Landing Ship, Tank). These seagoing assault vessels carried tanks and other vehicles during amphibious landings. The yard laid down 30 in 1944, taking only a month to complete one of the 328-foot vessels.
In all, Charlestown built 174 large vessels during the war, including 12 barracks ships and four submarines. There were also hundreds of smaller craft, such as wooden motor launches and diver boats. The South Boston Annex played a part in the yard’s strong wartime performance, doing much of the repair and conversion work and fabricating hull sections that were towed to Charlestown for incorporation into ships under construction.
Not all vessels were built outside: in the summer of 1942, shipfitters fabricated in their shop 150 fifty-foot LCMs (Landing Craft, Mechanized)—also called “tank lighters”—for the British-American invasion of North Africa. Shipfitter John Langan remembered it as a “crash program.... We just stopped everything else and concentrated on them and delivered them for the invasion.”
While this kind of rapid, assembly-line construction was Charlestown’s specialty during the war, there were other claims on the yard’s time. By late 1942 war’s reality was being brought home to Charlestown in the shape of battle-scarred ships needing quick repair. When a damaged ship arrived, it was given priority until it was ready to return to combat.
There was another reason for the air of urgency around war repairs: ship repair generally called for more skill than did shipbuilding. Because workers often had to work blind on battle damage until its nature and extent could be determined, such work called on all the workers’ resourcefulness. John Langan remembered “everybody fighting to get them [war-damaged vessels], because it is good work.” Langan recalled one vessel towed into the yard: it had been “torpedoed and cut right in halves ... and the fireroom was open to the seas ... [They had] tied her down with big I-beams ... tied them the full length, all the way around”—to keep the ship afloat until it reached the yard.
Even without the shell-torn hulls and shredded superstructures, war is hard on ships. Pushed faster, farther, and longer under less than ideal conditions, they needed more than routine maintenance. And on top of the already demanding schedule of ship construction, repair, and maintenance, other tasks competed for time and resources. Yard workers outfitted naval vessels built at other yards. They converted private vessels and old naval ships to wartime uses. They manufactured turbines and thousands of tons of die-lock chain (see pages [60-61]). They “degaussed” hulls—neutralized their magnetic fields so they would not trip mines. Together these activities suggest the scope and grueling pace of the yard’s war effort.
In such an atmosphere, mishaps caused by fallible humans dealing with complex machinery were inevitable. One particularly embarrassing, and nearly tragic, incident was related by electrical shop foreman Mel Hooper. His men were completing electrical work on the new submarine Lancefish (built at another yard) in 1945. “Some machinist went down,” he recalled, “and opened up the front gate on the torpedo tube and forgot to close it; then he went back in the ship and opened up the inside one and then it started to flood. And they had a hell of a job trying to close it, and they couldn’t close it, and everybody ran aboard the dock to get the hell out of there before they got drowned. And then the ship sank.”
The stepped-up safety program was almost certainly an improvement on the pre-war conditions, when, as remembered by plumber Lyman Carlow, “It seemed to me that everyone was supposed to look after himself.” But while the program called for more protections for workers from open machinery, hazardous fumes, and other dangerous conditions, a survey in 1944 noted that workers were rarely disciplined for safety violations, machines lacked guards, and most workers did not wear their hard hats, goggles, or ear protection. “You [went] down to the tanks with the chipping hammers and riveting guns going all around,” recalled Carlow, “and you wouldn’t be able to hear for a couple of hours afterward. But nobody did anything about it, or thought anything of it. You just got deaf, and that was it.”
A shipyard was a dangerous place to work even in peacetime; war multiplied the hazards. Charles Snell, an apprentice rigger at the yard, recalled 40 years later, “We had a lot of close escapes, because safety wasn’t really stressed then as much as it is today ... we lost a lot of riggers, strangely enough, and I can never account for this, being run over by the cranes ... the operator of the crane, when it was traveling, had very limited visibility close ahead. And we lost an inordinate number of riggers because they’d stumble and the crane would run over them.... We had quite a few falls into the dry dock, not riggers, but all trades.”
Snell left the yard in 1943 and served in Europe for the duration of the war. He recalled his impressions upon returning in 1946, comparing the yard to “a runner, which was running for an objective, and all of a sudden, the objective wasn’t there. The need for everything had suddenly evaporated. And it was a question of what do you finish and what don’t you finish, and what’s important.”
With peace came the end of Charlestown’s brief period as a major shipbuilding center. But the war-seasoned yard did not simply revert to what it had been before. Charlestown found a new postwar role as a place where old vessels were remade from the inside out, transformed into modern warships. Old did not necessarily mean long in years. In the 1950s, ships that had performed admirably in the late war were being left behind in a world of accelerating technological change. Charlestown extended their careers, installing state-of-the-art electronics. When advances in missile technology opened a new era in naval weapons and strategy, Charlestown played a leading role in the changeover. The life of the crowded and aging yard itself was extended by such activities, enabling Charlestown to render another three decades of service to the country.
In the months after war’s end, the level of activity naturally fell off, but the yard remained busy converting transports to bring home the troops, inactivating ships, and completing the last few LSTs, barracks ships, and subs laid down in 1945. Charlestown also carved a niche for itself in sonar, a technology dating to the World War I period and considered standard equipment since the 1930s. Beginning in 1948 the yard became a center for the repair of sonar equipment, establishing a sonar laboratory and developing techniques adopted by other electronics repair centers throughout the Navy.
Radar, developed in the 1930s, had come into widespread use during the war. The yard undertook a major conversion program in 1950 when it began upgrading radar and sonar systems on a number of destroyers and destroyer escorts, converting them to radar picket and antisubmarine warfare (ASW) roles. Charlestown also planned and designed all alterations, wherever they were performed, to cruisers, destroyers, escort carriers, LSTs, and several auxiliary vessel types.
While the yard accepted a variety of vessels, including aircraft carriers, it continued its traditional specialization in destroyers and destroyer escorts. In 1955 the yard converted the 10-year-old Gyatt into the world’s first guided missile destroyer.
That year the yard laid down the keel of its only postwar vessel and the last one it built: the LST Suffolk County, first of a larger and faster class of LSTs. Charlestown also served as the design yard for the other six LSTs, built in private yards.
In the 1960s the yard stayed busy with outfittings, missile and ASW conversions, and Fleet Rehabilitation and Modernization (FRAM) overhauls that added five to seven years of service to aging warships. Charlestown’s FRAM program specialized in World War II-era destroyers. Ranging from brief dockings to major operations of a year or more costing millions, these projects involved such sophisticated work as installing or upgrading sonar (see pages [76-77]), radar, communications, and computer equipment; major alterations such as replacing engines and entire superstructures; and the more prosaic tasks the yard had been performing for over a century: cleaning and painting hulls, renovating propellers and rudders, and rebricking or replacing boilers.
Nevertheless, by 1972 work was falling off at Charlestown, and signs did not bode well for the yard’s future. For years the Navy had invested little there for maintenance or modernization, making it harder to stay efficient. The marine railway and ropewalk had been shut down in 1971. Elsewhere, superfluous or inefficient military bases were being closed to save money. (The New York Navy Yard was closed in 1966.) A massive infusion of funds was needed to upgrade the old Charlestown yard—too small in any case for proper expansion of its facilities.
The Navy in general was retrenching for economic reasons. The destroyer fleet, especially—the lifeblood of the yard in the 20th century—had steadily dwindled since 1960. The fewer destroyers there were to service, the harder it was to justify the Charlestown yard’s existence. The failure of the Navy to carry through modernization plans, including one whereby the majority of the yard’s industrial activity would be transferred to an enhanced South Boston facility, helped to hasten the inevitable. Many associated with the yard also suspected that Massachusetts, as the only state going Democratic in the 1972 presidential election, would pay a penalty for failing to back the winner.
On April 16, 1973, the yard commander, Captain R. L. Arthur, announced that the Charlestown yard, along with the yard at Hunter’s Point in San Francisco, was to close. Over the next year it ceased all fleet servicing and manufacturing operations, and on July 1, 1974, nearly 175 years of service to the nation ended with a formal disestablishment ceremony. Only one naval activity remained at Charlestown: the protection and maintenance of the old warship long associated with the yard, U.S.S. Constitution.
The launching of a ship celebrates the time, energy, and skill spent in its making. Here U.S.S. Guest, one of 24 destroyers built at Charlestown during World War II, slips into Boston Harbor in 1942. The big Fletcher-class destroyer took only five months to build.
A destroyer is traditionally named for a distinguished naval figure, and if possible the closest female relative sponsors the namesake ship. In a centuries-old ritual, DD-461’s sponsor Eileen Fairfax Thomson breaks a bottle of champagne against the ship’s bow in 1941, sending it down the ways with the words, “I christen thee Forrest, and may God bless all who sail in her.” Captain French Forrest commanded the Charlestown-built Cumberland in the Mexican War. Siding with the Confederates during the Civil War, he oversaw conversion of the burned U.S.S. Merrimack into the ironclad C.S.S. Virginia—destroyer of Cumberland (see pages [28-29]).
Ships for World War II
From 1933 to the end of World War II, the Charlestown yard moved outside its traditional role as repair yard and became a shipbuilding facility. It began with destroyers—ships it had long specialized in repairing—averaging two a year in the 1930s. This period of steady production was preamble to the World War II crash building program. Charlestown launched almost 200 vessels, including 24 destroyers, between 1939 and 1945. In 1942 it began building destroyer escorts—smaller, less expensive versions of destroyers designed to counter German submarines. The final big program was the production of LSTs (Landing Ship, Tank) for amphibious assaults in Europe and Asia. LSDs (Landing Ship, Dock) for carrying other vessels; submarines; and various auxiliary vessels also came down the ways during the war. These programs spurred major changes at the yard. Greater specialization, for instance, broke up traditional shops. The biggest change was in construction methods, most notably prefabrication. Several bow and stern sections, each with its own keel, were built separately—many in the Shipfitters Shop, but also “in playgrounds and schoolyards and parts of the yard, and all around greater Boston,” remembered Rigger Charles Snell. These were then joined to the midship hull section rising on the shipways. “Economy was not the name of the game,” recalled Snell. “The name of the game was time.”
Hulls were launched from shipways or dry docks, then moored alongside piers for completion. Here, yard workers, who labored round the clock during the war, outfit a Fletcher-class destroyer as night falls. At top, a five-inch gun is lowered by a mobile crane.
Destroyer (36 built)
A fast, versatile, relatively small ship, it was equipped for anti-submarine warfare, escort duty, scouting, antiaircraft warfare, torpedo or gun surface engagement, and shore bombardment.
LST (Landing Ship, Tank; 44 built)
This craft carried tanks and other vehicles for amphibious landings. The water ballast system allowed it to vary its draft: deep for stable ocean travel and shallow for moving in close to shore.
Destroyer Escort (62 built)
This smaller, more quickly built version of the destroyer was designed to protect allied shipping convoys from German U-boats, freeing destroyers for other duties.
New Careers for Old Ships
During the long era of wooden sailing ships, when naval technology changed only gradually over the decades, a warship’s service lasted as long as the materials from which it was built. But as the pace of change quickened in the mid-19th century with the advent of steam propulsion and iron hulls, a vessel quickly grew obsolete without continual incorporation of the latest technology. This state of affairs, which intensified in the 20th century, provided Charlestown Navy Yard with a new role after World War II: lengthening or transforming the careers of old ships, otherwise destined for mothballs, through modernization and conversion. Modernization meant updating old electrical, propulsion, or weapons systems or performing structural surgery without altering the vessel’s function. This ranged from installing a sonar dome on the bottom of the hull to dismantling the entire superstructure and building a new one. The process normally took several months. Conversion, which could take years, involved major alteration of a vessel to prepare it for a different tactical mission. A typical example would be the conversion of a conventional scouting, escorting, and submarine-fighting destroyer to a radar picket destroyer, whose role was to provide mid-ocean radar warning. A notable postwar task undertaken by the yard was the 1956 conversion of the destroyer Gyatt into the world’s first guided missile destroyer. Basically, the vessel’s aft five-inch guns were replaced with a twin missile launcher. But the ship had to be significantly altered to perform its new function. The yard designed automated systems that first affixed a booster charge to the missile and then moved it from the air-conditioned belowdecks magazine to the launcher. The decks and superstructure had to be reinforced to withstand the tremendous pressure and temperature of a launch. A system of ducts and blowout plates was installed to minimize damage and injury in the event of a premature explosion. Innovative retractable fins at midships helped stabilize the vessel for firing. With these and other changes, the yard remade Gyatt into a sophisticated missile-firing machine.
In the late 1950s the Navy began installing sonar equipment in bow domes. Bow domes reduced hull resistance and were less susceptible to bubble noise. The Charlestown yard, already a leader in sonar technology, performed a prototype dome installation in 1958. To install a dome, workers first cut away part of the old bow, then fitted the prefabricated dome ([next page], on U.S.S. Willis A. Lee in 1961).
Sonar works actively and passively. In active sonar, the transducer in the dome transmits sound pulses through the water. When the pulses reach an object (or the bottom), they are reflected and received by the transducer as echoes. Distance is determined by time elapsed between transmission and echo. In passive sonar, hydrophones pick up noises generated by underwater sources.
