Previously referred to as the "Old Boyer Firm" that had been known for canal towing, and coal barge operations on the Schuylkill River from Philadelphia to Pottsville, Pennsylvania reorganized in 1928 to become Interstate Oil Transport.
In 1931, Interstate Oil Transport was approached by a man by the name Thornton Dayton Hooper. Thornton who had been a schooner captain that later enlisted in the American army during World War I. While in combat, Thornton was injured and his foot had been amputated above the ankle. Following the war, Thornton worked for a company called S.C. Loveland. At the time Thornton was supporting a family of five sons had been seeking out new opportunities, at the behest of his wife.
He approached Lewis Boyer of Interstate Oil Transport with an idea to service and establish a route on the Cape Fear River from Wilmington, North Carolina to Fayettville, North Carolina. Although a route from Philadelphia to Wilmington had already been established via the Intercoastal Waterway, or utilizing coastal tankers. An extension via the Cape Fear River would allow for product to be delivered to the Piedmont Region. Thornton worked for a year with no salary, his agreement would result in him becoming a partner if the proposal was successful.
The refineries of Philadelphia had been established at the time to handle product that was coming out of Oil City, Pennsylvania (this was one of the first petroleum wells in world located in Western Pennsylvania.) Philadelphia was the largest refining center until the second decade of the twentieth century. As the need for Petroleum products grew (kerosene, heating oil, diesel fuel, lubricants and asphalt). However, the demand exceeded for gasoline forced the refineries to seek more crude oil, far beyond the capacity that railroads could provide.
Interstate Oil Transport began serving this demand, transporting the oil from refineries to points along the Delaware River that included South Jersey, and eastern Pennsylvania. The equipment at the time consisted of wooden scow barges with steel tanks fitted to their decks. The tugs were powered by coal-fired steam engines.
Interstate Operated on the route Thornton establishedfor two years. In 1937, Thornton oversaw the construction of the Interstate 8. A new barge being built for Interstate by Gulfport Shipbuilding of Port Arthur, Texas. That particular barge remained in service forty five years after her construction.
In 1940, Thornton was brought into partial ownership of Interstate. Several managers at Interstate Oil Transport took portions of the ownership through the 1940's (Robery Burrett, Ed Burrett, Horace Pugh and John Kulak) Thornton Hooper oversaw operations and participated in ownership. Throughout the 1940's IOT serviced two areas. In the Delaware River IOT serviced the local refineries to terminals in the Schuylkill River, these served as distribution points for heating oil. This service area included Wilmington, Delaware. The second operating area was in the Chesapeake Bay including Yorktown, Virginia; Baltimore, Annapolis; and Easton, Maryland. Service was provided in the Potomac River to Washington, D.C. however Steuart Transportation became the primary provider in that region.
By 1977, IOT was carrying approximately 230 million barrels per year. as measured in dead weight tonnage, or gross tonnage IOT represented the largest capacity fleet of U.S. flagged vessels. This marked the beginning of IOT's expansion; at the time petroleum barges carried between 16,000 bbls and 17,000 bbls of product (this upper limit was imposed by the New York State Barge Canal). The Thornton Brothers saw opportunities in moving larger barges with larger tugs, in 1960 the decision was made to build a new 40,000 bbl barge. As the size of IOT's barges grew larger tugs where necessary.
After Adrian and his father Thornton visited Main Iron Work in Houma, Louisiana the decision was made to construct the new vessels at the yard. The result was the tug Interstate Transporter, the second was the Mariner. In total Main Iron Works built a total of thirty two boats for IOT. These tug represented innovations in tug design. It was found that the tugs Mariner and Explorer where able to operate in ice bound markets that other tugs where unable to. Other innovations include the first 12 cylinder Fairbanks-Morse turbo charged engine in marine operation that was rated at 3,000 horsepower. Although it was untested IOT installed it in the tug Mariner (the largest engines at the time ran around 1,250 horsepower to 1,600 horsepower) Another was the concept of 110-volt A/C current to East Coast tugs, IOT moved the crew's quarters from the fore peak to regular quarters on the main deck level, as well as fitting fire monitors on top of the tug's wheelhouses.
The 1960's saw further expansions, by this time IOT began to focus on petroleum transportation in lieu of general towing. Interstate Oil Transport had two fleets. There was the Northeast Fleet (Green Fleet) operated in Philadelphia, Pennsylvania. And a Southern Fleet (White fleet) operated out of Tampa, Florida.
During the 1970's IOT reached the peak of it's operations. However, the 1970's proved turbulent for IOT. With key members of managment approaching retirement age there where no family members of age that could assume a position within IOT as a result, in 1974 IOT entered into a merger with Cities Service Tanker Company, but that merger dissolved by 1978.
In early 1981, IOT began to establish an arrangement with a company called Southern National Gas ( which at the time had modified their name to Southern Natural Resources, they were also known for a time as SONAT Marine) SONAT subsequently purchased Interstate Oil Transport. SONAT maintained centers in Norfolk, Virginia; Tampa, Florida; Pascagoula, Mississippi; and Port Arthur, Texas they served two dozen major ports as well as smaller ports in the Delaware River, Chesapeake Bay and the East Coast from Maine to Georgia, as well as the Florida and the Gulf Coast.
Meanwhile, some managers at SONAT Marine offered to form a partnership to raise the funds necessary to purchase the SONAT Marine subsidiary. These eleven partners included some who had worked for IOT since the 1950's. On April 14, 1987 Maritrans Partners, LP assumed control of SONAT's tug and barge business.
However, in March of 1989 the Exxon Valdez ran aground in Prince William Sound; in 1990 the Oil Pollution Act of 1990 was passed calling for the double hulling of all petroleum carrying vessels by 2010 as well as other stipulations that effected Maritrans including manning, preparedness and spill prevention. Maritrans filed suit to fight the stipulations set fourth by OPA '90.
Maritrans had begun to consolidate its business by the mid 1990's by first backing out of the black oil trade and carry only petroleum products and petrochemicals. The phosphate trade and local transport in Baltimore that was part of the Harbor Towing subsidiary did not fit into Maritrans's new business model. As Maritrans backed out local companies moved in that included Bouchard Transportation of New York and Vane Brothers of Baltimore.
As 1993 arrived, Maritrans was incorporated and formed as a Delaware corporation (in simple terms) the company became publicly traded and was listed under "TUG" on the New York Stock exchange. 1994, saw the retirement of three of the original eleven partners.
By 1998 Maritrans began to thin their northeast fleet, eleven tugs where put up for sale. Eight of the tugs and where acquired by K-Sea Transportation of New York, New York; three tugs were purchased by Reinauer Transportation of New York, New York, and three were acquired by Vane Brothers of Baltimore, Maryland; other tugs where bought by companies all over the world.
Maritrans retained the bulk of their 5,600 - 6,000 horsepower "married" units. In 1999, a Federal Claims court dismissed a suit initiated by Maritrans in August of 1996, that attempted to block regulations set fourth by OPA '90. Maritrans subsequently signs a contract to double hull the barge Ocean 244.
However, in 2006, Maritrans Inc. was acquired by Overseas Ship holding Group (OSG). The acquisition significantly expanded OSG's U.S. Flag presence with the addition of twenty one articulated tug barges and "handy size" product carriers.