Luna (tugboat)

From SpottingWorld, the Hub for the SpottingWorld network...
LUNA (tugboat)
U.S. National Register of Historic Places
U.S. National Historic Landmark
Location: NDC pier, Boston, Massachusetts
Coordinates: 42°22′4″N 71°4′27″W / 42.36778°N 71.07417°W / 42.36778; -71.07417Coordinates: 42°22′4″N 71°4′27″W / 42.36778°N 71.07417°W / 42.36778; -71.07417
Built/Founded: 1930
Architect: Alden, John G., & Co.; Davis, M.M. & Sons
Governing body: Private
Added to NRHP: October 6, 1983[1]
Designated NHL: April 11, 1989[2]
NRHP Reference#: 83004099

The Luna (tugboat) is a historic tugboat in Boston, Massachusetts. The Luna was built in 1930 by John G. Alden and M.M. Davis. It is listed on the National Register of Historic Places and is a U.S. National Historic Landmark.

The American tugboat Luna is today (2009) the last surviving full-sized wooden ship-docking tug on the US Gulf and Atlantic coasts and is the world's first diesel-electric tugboat build for commercial service. These two distinctions have led to designation of the Luna as a US National Historic Landmark. Today the Luna is preserved in Boston, Massachusetts, where its rehabilitation process has been underway since the tug was rescued from being broken up in 1995. The Luna is the responsibility of the Preservation Society and its progress is recorded in their website. Due to her wartime service with a civilian crew, the Luna is also a member of the Naval Historic Vessel Association.

Vessel Design and History

The 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, the aesthetics of the Luna 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's General Electric Corporation, 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.

The Luna's wooden hull and deckhouses were built by the M.M. Davis Shipbuilding Company in Solomons, Maryland. The empty hull was towed from the Chesapeake to East Boston for outfitting at the Bethlehem Steel Shipyard in East Boston.

Upon completion, the 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.

The Luna and her sister, the Venus, were the best boats in the Boston Towboat fleet and therefore were the "first boats" to be assigned every day. Not only were the two tugs the most powerful tugs, they were also the most reliable, and the most efficient. 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 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. One hour they might be operating in the main ship channel, another hour they might find themselves far up the Chelsea Creek, the Mystic River, the Charles River, the Fort Point Channel, Island Creek, the Reserve Channel of South Boston, handling a ship at Quincy or Salem, or handling warships in the Boston Naval Shipyard. The tugs occasionally operated between Maine and New York on assignments.

World War II

During World War II, the Luna was mobilized by the US Navy and US Army and used as a civilian-crewed and privately-owned and managed tugboat at shipyard, repair yards, terminals, piers and anchorages from Bath, ME and the Cape Cod Canal. The Luna handled the many ships launched at the yard, 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. The Luna was the flagship of the Boston Towboat fleet until the end of World War II, when modern surplus war-built tugs were sold off by the government. General Electric was so proud of the Luna that its marine advertisements featured the Luna into the early 1950s, a period that spanned almost two decades. During the 1930s, post war 1940's and early 1950s, Luna assisted the U.S.S. Constitution with its annual turnaround.[3]


As more powerful diesel tugs and diesel-electric tugs were delivered to Boston Towboat, the 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. The Luna's fortunes improved over the next 16 years. She was restored on a shoestring budget by Captain Frances Rose Gage and an army of volunteers. Without the efforts of "Tugboat Franny" both the Luna and her sister ship, the Venus would be worm food. The Luna Preservation Society took responsibility for her in 1995. Luna was declared a National Historic Landmark in 1989.[2][3] Since being rescued from a graving dock in East Boston in early 1995, the Luna has been rehabilitated for her role in Boston Harbor as an operating Landmark and educational vessel.

In October, 2000 the Luna was towed to Boothbay Harbor, Maine to begin a major overhaul of her hull structure and returned to Boston in May 2002. In October 2007, the 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

The Luna has been undergoing continuous rehabilitation by volunteers and shipyard personnel since October 2007. It is expected that by early 2010 the rehabilitation process will be substantially complete. At that time, the Luna expects to be on display to the public in Boston Harbor and open on certain weekend days.

Particulars of the Luna

Length Overall 100.0 feet Length Between Perpendiculars 90.3 feet Breadth (width of hull) 24.8 feet Depth (main deck to keel) 18 feet Draft fully loaded 13 feet Height above waterline (fixed) 24.6 feet Gross Tonnage (cubic) 165 tons Net Tonnage (cubic) 112 tons Displacement fully loaded 325 tons Displacement light ship 315 tons Engine horsepower 760 Motor horsepower 600 Top speed running free 13knots Fuel capacity 4,000gallons (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 Engines - two Winton 6 -cylinder in-line diesel engines produce 380 hp each at 300 rpm. create the power that is converted into direct electric current. Engines are four-cycle (inlet, compression, power, exhaust) and have fresh water cooling by a sea water heat exchanger.

Generators - two General Electric direct current generators of 250 kilowatts each connected to the main engines create the electricity that is delivered to the main propulsion motor.

Exciters - two General Electric exciters are located aft of each generator, directly connected to a diesel engine. Exciters induce a current in the rotating armature of the generators.

Switchboard - one General Electric deadfront switchboard controls the creation of electricity by the generators and the delivery of electricity to the motor.

Motor - one General Electric 400 kW (600 hp) DC electric motor with armatures, directly connected to the propeller shaft turns the propeller shaft and the propeller. The motor is controlled directly from the steering stations.

Propeller - one iron, four-bladed propeller. transforms the rotation of the propeller shaft into lift on the propeller's forward surfaces and pulls the tug and its payload.

Compressors - two compressors and four compressed air storage tanks are used to crank start the diesel engines prior to the introduction of diesel fuel. The Luna's horn is also air-powered.

Pumps- the 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 barges and ship in case of an emergency, and a fire pump to deliver water to several hydrants for fire-fighting and deck washing. Galley water is delivered by hand pump.

Batteries- a set of batteries is installed to store emergency electric power for lighting and starting the compressors.

Condensers-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.

Steering Engine-is an electro-hydraulic motor-driven winch that takes directions from the steering wheel and pulls a steering cable connected through pulleys to the tug's rudder from port to starboard.


White Oak - a strong, dense wood Outboard hull planking Pilothouse planking Keels and keelsons Hull structure and frames Knees to connect right angles

Cypress-a highly rot resistant wood Main deck house planking Boat deck (also called the "Texas")and Pilothouse decking Bulwark planking (original) replaced by cedar (rehabilitation)

Douglas Fir - straight-grained and strong Main deck planking Fore and aft masts

Live Yellow Pine - rot resistant and flexible Inboard hull "ceiling" planking, deck beams, deckhouse coamings, deckhouse studs

Locust-a tough wood that expands Wooden "treenails" called trunnels to nail wooden planks to frames in drilled holes


  1. "National Register Information System". National Register of Historic Places. National Park Service. 2007-01-23. 
  2. 2.0 2.1 "LUNA (Tugboat)". National Historic Landmark summary listing. National Park Service. Retrieved 2008-07-06. 
  3. 3.0 3.1 Kevin Foster (August 5, 1988). National Register of Historic Places Registration: Luna / Tugboat LunaPDF (32 KB). National Park Service  and Accompanying one photo, Luna escorting Normandie in New York harbor, from 1935PDF (32 KB)

External links