Algonquin Gas & Transmission Hubline

The Algonquin Gas Transmission is a 1,100 miles long pipeline system, which delivers natural gas to New England. It is connected to the Texas Eastern Pipeline and the Maritimes & Northeast Pipeline. The Algonquin Gas Transmission pipelines transport about 20 billion cubic meters of natural gas per annum. It generally receives gas that originated in the Gulf of Mexico, although it also receives gas from an LNG terminal in Massachusetts.

CASHMAN was part of the team that installed a 29-mile underwater gas and transmission line from Beverly to Quincy, Massachusetts. CASHMAN'S team designed, furnished and installed a critical cofferdam in Beverly Harbor to connect a portion of the gas main installed by shallow rock boring with the cut & cover main. This connection was made with the rock at or near the surface of the seabed, and required an innovative approach to design and construction. 


  • As a subcontractor to Horizon Offshore Contractors (now Cal Dive Int’l.), CASHMAN provided support of pipe fabrication and placement. 
  • As a subcontractor to Michels Corp., CASHMAN provided support of horizontal directional drilling (HDD) work including the installation of steel piles to support the drill strings. 
  • CASHMAN worked directly for owner Algonquin/Spectra, providing welding services, testing support, and the furnishing and installation of the gas main backfill for nearly the entire exposed 29-mile length of the main. 
  • This operation featured the creative use of dump scows and positioning barges to deposit a precise amount of rock backfill directly onto the gas main. 

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Algonquin Gas & Transmission Co. of Spectra Energy Corp.
$30 million
2003 - 2004