The Massachusetts Port Authority will increase the height of two container cranes at its Conley Terminal so vessels stacked high with containers can be unloaded at high tide.
At present, large, fully loaded containerships must be unloaded at low tide
because of the height limitations of the cranes.Work on one of the Paceco cranes at the South Boston terminal is due to be completed by the end of November, while the second crane is scheduled to be raised by Dec. 5, officials said. The contractor on the complex job is Thomas O'Connor and Co., based in Canton, Mass.
The $2.8 million job will increase the height of both cranes from 125 feet at mean low water to 145 feet, said Lana Razdan, Massport spokeswoman.
Twenty-foot fabricated steel inserts will be placed in each leg of the cranes. A computerized jacking system will be used to lift the top of each 900-ton crane while the inserts are set and welded in place.
Thomas O'Connor, president of the contracting firm, said the job calls for ''zero downtime" so that incoming vessels can be unloaded within 24 hours of arrival notice.
The crane work is part of a $50 million capital investment program for Conley over the next four to five years, said Alden S. Raine, Massport's executive director. The upgrade includes a 950-foot berth extension, an increase in back-lot storage space and the addition next year of two new cranes to serve post-Panamax containerships (vessels that are too wide to travel the Panama Canal).
The development still leaves some uncertainty over how containers unloaded at Conley will reach a proposed double-stack rail service at Massport's other facility, Moran Terminal in Charlestown, at the other end of Boston Harbor.
Officials said consideration is being given to both trucking and barging
from Conley, which is a more convenient way to reach open water. Either operation would raise costs, however, cutting into the benefits of double- stack efficiency at Moran.
The proposed stack line would be operated jointly by Guilford Transportation Inc. of North Billerica, Mass., and Canada's CP Rail System. Massport officials said no similar dockside service is expected at Conley
because existing Consolidated Rail Corp. tracks there run through South Boston streets.