Several dozen protesters carrying placards reading "Local People, Local Jobs" marched Friday at Eighth and Market Streets, complaining that Aker Philadelphia Shipyard and its scaffolding contractor had turned their backs on local workers.

The timing came as a surprise because, while many members of Aker's regular unionized workforce were laid off during the recession and a downturn in shipbuilding in 2010, they have been recalled and are back on the job.

Employment at the nation's second-largest commercial shipbuilder is 1,100 - what it was in July 2010.

Lou Agre, president of the Philadelphia Metal Trades Council, the collective bargaining representative for 11 unions, said he did not know anything about the protest when initially told about a notice e-mailed Thursday to news organizations.

The dispute apparently stems from a change in a subcontractor.

The former scaffolding contractor, Safway Services L.L.C., decided not to renew its contract with Aker. Safway used laborers from the carpenters' union.

A new contractor, Diamond Scaffold Services Group Inc., does not use the carpenters' union and, according to leaflets distributed by marchers Friday, employs out-of-state workers, "adding on to the increasing number of out-of-state workers that are employed at the yard."

The leaflet said: "We are local workers who were recently laid off. ... We are appealing to the general public to tell our side of the story."

Edward Coryell Sr., leader of Carpenters District Council, could not be reached for comment.

Aker said Friday: "We have more people from the tristate area here today than we did 12 months ago."

The only recent shift in work practices was a change last summer in scaffolding subcontractors, Aker said. Diamond employs 30 to 40 scaffold builders, Aker said.