''Luna'' is a historic

tugboat A tugboat or tug is a marine vessel that manoeuvres other vessels by pushing or pulling them, with direct contact or a tow line. These boats typically tug ships in circumstances where they cannot or should not move under their own power, su ...

normally berthed in

Boston Harbor, Massachusetts Boston Harbor is a natural harbor and estuary of Massachusetts Bay, and is located adjacent to the city of Boston, Massachusetts. It is home to the Port of Boston, a major shipping facility in the northeastern United States. History Since ...

. ''Luna'' was designed in 1930 by John G. Alden and built by M.M. Davis and Bethlehem Steel. She is listed on the

National Register of Historic Places The National Register of Historic Places (NRHP) is the United States federal government's official list of districts, sites, buildings, structures and objects deemed worthy of preservation for their historical significance or "great artistic v ...

and is a U.S.

National Historic Landmark A National Historic Landmark (NHL) is a building, district, object, site, or structure that is officially recognized by the United States government for its outstanding historical significance. Only some 2,500 (~3%) of over 90,000 places listed ...

. In 1985, the Luna was designated as a

Boston Landmark A Boston Landmark is a designation by the Boston Landmarks Commission for historic buildings and sites throughout the city of Boston based on the grounds that it has historical, social, cultural, architectural or aesthetic significance to New Engla ...

by the

Boston Landmarks Commission The Boston Landmarks Commission (BLC) is the historic preservation agency for the City of Boston. The commission was created by state legislation i1975 History Urban renewal in the United States started with the Housing Act of 1949, part of Preside ...

. ''Luna'' is the last surviving full-sized wooden ship-docking tug on the US Gulf and Atlantic coasts and was the world's first diesel-electric tugboat built for commercial service. These two distinctions have led to designation of ''Luna'' as a US National Historic Landmark. Today ''Luna'' is preserved in Boston Harbor, where her rehabilitation process has been underway since the tug was rescued from being broken up in 1995. ''Luna'' is the responsibility of the Luna Preservation Society and its progress is recorded in their website. Due to her wartime service with a civilian crew, ''Luna'' is also a member of the Naval Historic Vessel Association.

Vessel design

''Luna'' was designed by John G. Alden (1884–1962), one of America's greatest and most prolific yacht designers, but was heavily influenced by the preferences of the tug's owner, the Mystic Steamship Company, and its subsidiary Boston Tow Boat Company. As a result, ''Luna''s aesthetics embody the classical sweeping profile of the American harbor tug. The tugboat also had a very innovative propulsion plant: two diesel engines, each turning a generator and exciter to create DC current, which was then shunted (via prototypical switchboards) to a single DC motor (weighing 20 tons) attached to a single propeller shaft. The project was a showpiece for

Thomas Edison Thomas Alva Edison (February 11, 1847October 18, 1931) was an American inventor and businessman. He developed many devices in fields such as electric power generation, mass communication, sound recording, and motion pictures. These inventio ...

General Electric Corporation General Electric Company (GE) is an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, and incorporated in New York (state), New York state and headquartered in Boston. The company operated ...

, which seized the challenge to design, build and deliver the components, in conjunction with their control subcontractors. Six years after ''Luna''s delivery, GE reported that there were 33 diesel-electric tugs in service, 21 of which were GE installations. ''Luna''s wooden hull and deckhouses were built by the M.M. Davis Shipbuilding Company in

Solomons, Maryland Solomons, also known as Solomons Island, is an unincorporated community and census-designated place (CDP) in Calvert County, Maryland, United States. The population was 2,368 at the 2010 census, up from 1,536 in 2000. Solomons is a popular weekend ...

. The empty hull was towed from the Chesapeake to East Boston for outfitting at the Bethlehem Steel Shipyard in East Boston.

Operational history

Boston harbor

Upon completion, ''Luna'' was delivered to the Mystic Steamship Company of Boston as the first diesel-powered tug in their fleet. All the other tugs in the Mystic Steamship fleet - commercially known as the Boston Towboat Company - were powered by coal and oil-fired boilers and steam engines. The Mystic Steamship Company could trace its roots to the Boston Towboat Company, which had been founded by Boston's maritime executives to assure salvage, icebreaking, and ship towing services in 1857. The Mystic Steamship Company operated coal-carrying colliers and coal barges to transport coal from railroad piers in New York Harbor, Philadelphia, Baltimore and Newport News. This coal was used as a fuel, and as the basis to make lamp gas from coal and coke. Later, Boston Towboat was operated by Eastern Enterprises, owners of Boston Gas and various maritime operations, which is active to this day as Eastern Enterprises. ''Luna'' and her sister, ''Venus'', were the most powerful, reliable, and efficient boats in the Boston Towboat fleet and therefore were the first boats to be assigned every day. The majority of the tug's work involved docking and undocking ships in every part of greater Boston Harbor, from Salem's coal-fired powerplants and industries in the north, to

Plymouth Plymouth () is a port city and unitary authority in South West England. It is located on the south coast of Devon, approximately south-west of Exeter and south-west of London. It is bordered by Cornwall to the west and south-west. Plymouth ...

harbor in the south. Most of the time, the tugs were busy pushing and towing tankers, freighters, refrigerated cargo ships, passenger liners, warships, and large barges within Boston Harbor including

Chelsea Creek Chelsea Creek, shown on federal maps as the Chelsea River, is a waterway that runs along the shore of Chelsea, Massachusetts, and separates that community from the cities of Boston and Revere, as well as feeding part of the current Belle Isle ...

, the

Mystic River The Mystic River is a riverU.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed April 1, 2011 in Massachusetts, in the United States. In Massachusett, means "large estuary," alluding to t ...

, the

Charles River The Charles River ( Massachusett: ''Quinobequin)'' (sometimes called the River Charles or simply the Charles) is an river in eastern Massachusetts. It flows northeast from Hopkinton to Boston along a highly meandering route, that doubles b ...

and

Fort Point Channel Fort Point Channel is a maritime channel separating South Boston from downtown Boston, Massachusetts, feeding into Boston Harbor. The south part of it has been gradually filled in for use by the South Bay rail yard and several highways (specif ...

. They occasionally operated on assignments as far away as

Maine Maine () is a state in the New England and Northeastern regions of the United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Canadian provinces of New Brunswick and Quebec to the northeast and north ...

and

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

World War II

During

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

, ''Luna'' was mobilized for service with the

US Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of ...

and

US Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...

. She was used as a civilian-crewed and privately owned and managed tugboat at shipyards, repair yards, terminals, piers and anchorages from

Bath, Maine Bath is a city in Sagadahoc County, Maine, in the United States. The population was 8,766 at the 2020 census. It is the county seat of Sagadahoc County, which includes one city and 10 towns. The city is popular with tourists, many drawn by its ...

to the

Cape Cod Canal The Cape Cod Canal is an artificial waterway in the U.S. state of Massachusetts connecting Cape Cod Bay in the north to Buzzards Bay in the south, and is part of the Atlantic Intracoastal Waterway. The approximately canal traverses the neck o ...

. ''Luna'' handled the many ships launched at the yards, guided damaged ships into drydock, took over the towing of damaged ships in the harbor from seagoing rescue tugs, undocked warships, transports and troopships bound for war, towed barges laden with ammunition, stores and fuel. She greeted returning warships and troop ships at the end of the war. ''Luna'' was the flagship of the Boston Towboat fleet until the end of the war, when modern surplus war-built tugs were sold off by the government. General Electric was so proud of ''Luna'' that its marine advertisements featured ''Luna'' into the early 1950s, a period that spanned almost two decades. During the 1930s, post war 1940s and early 1950s, ''Luna'' assisted the with her annual turnaround.

Postwar service and retirement

As more powerful diesel tugs and diesel-electric tugs were delivered to Boston Towboat, ''Luna'' was gradually relegated to back-up status and was retired in 1971. The tug was then used as an office and floating home, until it was acquired by a non-profit research institution in 1979. She was maintained on a shoestring budget by Captain Frances Rose Gage and many volunteers but sank twice in this period. The ''Luna'' Preservation Society took responsibility for her in 1995. ''Luna'' was declared a National Historic Landmark in 1989.
Since being rescued from a graving dock in East Boston in early 1995, ''Luna'' has been rehabilitated for her role in Boston Harbor as an operating Landmark and educational vessel. In October, 2000 ''Luna'' was towed to

Boothbay Harbor, Maine Boothbay Harbor is a town in Lincoln County, Maine, United States. The population was 2,027 at the 2020 census. It includes the villages of Bayville, Sprucewold, and West Boothbay Harbor. During summer months, the entire Boothbay Harbor regio ...

to begin a major overhaul of her hull structure and returned to Boston in May 2002. In October 2007, ''Luna'' began a major rehabilitation of all three decks (pilothouse roof, boat deck, and main deck) as well as deckhouse structure and coamings. This work was completed in May 2008 and was followed immediately by cleaning and coating of all original machinery and steel structure in her engine room. Plans are being developed for the installation of a small, modern diesel engine for "shadow" propulsion of the tug, permitting the original machinery to be restored to its original appearance, despite its corrosion damage suffered when the tug sank in fresh and salt water in the late 1980s and early 1990s.

Current status

''Luna'' has been undergoing continuous rehabilitation by volunteers and shipyard personnel since October 2007.

Specifications

*Length Overall *Length Between Perpendiculars *Breadth (width of hull) *Depth (main deck to keel) *Draft fully loaded *Height above waterline (fixed) *Gross Tonnage (cubic) 165 tons *Net Tonnage (cubic) 112 tons *Displacement fully loaded 325 tons *Displacement light ship 315 tons *Engine horsepower *Motor horsepower *Top speed running free *Fuel capacity (4 tanks) *Operating range about 30 days at full power *Harbor day shift crew typical service: 5 persons (Captain, Chief Engineer, Cook, Deckhand, Oiler) *Minimum crew required in 1930: 3 persons (captain, chief engineer, deckhand) *Total crew accommodations: 9 berths

Main machinery components

There are two Winton 6-cylinder, in-line

diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...

s produce each. At 300 rpm, they create the power that is converted into direct electric current. Two

General Electric General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energ ...

direct current generators, of 250 kilowatts each, are connected to the main engines and create the electricity that is delivered to the main propulsion motor. Aft of each generator is a General Electric exciters, directly connected to a diesel engine. Exciters induce a current in the rotating armature of the generators. The engines are

two-cycle A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being completed in one revolution of t ...

and have fresh water cooling by a sea water

heat exchanger A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contac ...

. Salt water/fresh water condensers are installed port and starboard to cool the fresh water that is circulated through the diesel engines to cool the engine blocks. The fresh water loops are surrounded by circulating sea water. One General Electric deadfront switchboard controls the creation of electricity by the generators and the delivery of electricity to the motor which is a General Electric DC electric motor with armatures. It is directly connected to the

propeller shaft A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power and torque and rotation, usually used to connect ...

and turns the iron, four-bladed

propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...

. The motor is controlled directly from the steering stations. Two

compressors A compressor is a mechanical device that increases the pressure of a gas by reducing its volume. An air compressor is a specific type of gas compressor. Compressors are similar to pumps: both increase the pressure on a fluid and both can transp ...

and four compressed air storage tanks are used to crank-start the diesel engines prior to the introduction of

diesel fuel Diesel fuel , also called diesel oil, is any liquid fuel specifically designed for use in a diesel engine, a type of internal combustion engine in which fuel ignition takes place without a spark as a result of compression of the inlet air and t ...

. ''Luna''s horn is also air-powered. A set of batteries is installed to store emergency electric power for lighting and starting the compressors. ''Luna'' is equipped with various pumps, including a fuel transfer pump, to shift fuel from one fuel tank to another and to a day tank, a bilge and salvage pump, to pump water from the tug and from

barge Barge nowadays generally refers to a flat-bottomed inland waterway vessel which does not have its own means of mechanical propulsion. The first modern barges were pulled by tugs, but nowadays most are pushed by pusher boats, or other vessels ...

s and ships in case of an emergency, and a fire pump to deliver water to several

hydrant A hydrant is an outlet from a fluid main often consisting of an upright pipe with a valve attached, from which fluid (e.g. water or fuel) can be tapped. Depending on the fluid involved, the term may refer to: * Fire hydrant for firefighting water ...

s for fire-fighting and deck washing.

Galley A galley is a type of ship that is propelled mainly by oars. The galley is characterized by its long, slender hull, shallow draft, and low freeboard (clearance between sea and gunwale). Virtually all types of galleys had sails that could be used ...

water is delivered by

hand pump Hand pumps are manually operated pumps; they use human power and mechanical advantage to move fluids or air from one place to another. They are widely used in every country in the world for a variety of industrial, marine, irrigation and leis ...

. There is also a steering engine which is an electro-hydraulic motor-driven

winch A winch is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the tension of a rope or wire rope (also called "cable" or "wire cable"). In its simplest form, it consists of a spool (or drum) attache ...

that takes directions from the steering wheel and pulls a steering cable connected through pulleys to the tug's

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to ...

from port to starboard.

Woods used in construction

Several different kinds of wood are used in the construction of the ''Luna''.

White Oak The genus ''Quercus'' contains about 500 species, some of which are listed here. The genus, as is the case with many large genera, is divided into subgenera and sections. Traditionally, the genus ''Quercus'' was divided into the two subgenera '' ...

is a strong, dense wood used for outboard hull planking, pilothouse planking,

keel The keel is the bottom-most longitudinal structural element on a vessel. On some sailboats, it may have a hydrodynamic and counterbalancing purpose, as well. As the laying down of the keel is the initial step in the construction of a ship, in Br ...

s and

keelson The keelson or kelson is a reinforcing structural member on top of the keel in the hull of a wooden vessel. In part V of “Song of Myself”, American poet Walt Whitman Walter Whitman (; May 31, 1819 – March 26, 1892) was an Ame ...

s, hull structure and frames, and

knees In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...

to connect right angles.

Cypress Cypress is a common name for various coniferous trees or shrubs of northern temperate regions that belong to the family Cupressaceae. The word ''cypress'' is derived from Old French ''cipres'', which was imported from Latin ''cypressus'', the ...

is a highly rot-resistant wood used for main deckhouse planking, boat deck (also called the "Texas") and pilothouse decking, and bulwark planking (original). It is being replaced by cedar during restoration.

Douglas Fir The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three va ...

is a straight-grained and strong wood used for main deck planking, and fore and aft masts. Live

Yellow Pine In ecology and forestry, yellow pine refers to a number of conifer species that tend to grow in similar plant communities and yield similar strong wood. In the Western United States, yellow pine refers to Jeffrey pine or ponderosa pine. In the S ...

is rot-resistant and flexible; it is used for inboard hull "ceiling" planking, deck beams, deckhouse coamings, and deckhouse studs.

Locust Locusts (derived from the Vulgar Latin ''locusta'', meaning grasshopper) are various species of short-horned grasshoppers in the family Acrididae that have a swarming phase. These insects are usually solitary, but under certain circumstanc ...

is a tough wood that expands. It is used for wooden

treenail A treenail, also trenail, trennel, or trunnel, is a wooden peg, pin, or dowel used to fasten pieces of wood together, especially in timber frames, covered bridges, wooden shipbuilding and boat building. It is driven into a hole bored through two ...

s, also called trunnels, to fasten wooden planks to frames in drilled holes.

References

External links

*
Tugboat Luna Preservation Society
* City of Boston
Landmarks CommissionTugboat Luna Study Report
1985 {{DEFAULTSORT:Luna (Tugboat) National Historic Landmarks in Massachusetts Museum ships in Massachusetts Tugboats of the United States Ships on the National Register of Historic Places in Massachusetts 1930 ships Boston Harbor National Register of Historic Places in Boston Landmarks in Boston National Register of Historic Places in Chelsea, Massachusetts