A group of developers is hoping to win voter approval Tuesday of a plan to build a deck over a downtown San Diego shipping terminal to create space that could be used for a new sports stadium.

Proposition B would change the Port of San Diego's master plan to allow the development of a 40-foot-tall deck over the 96-acre 10th Avenue Marine Terminal on downtown's San Diego Bay.

Supporters, led by developer Frank Gallagher, said the project would create land that could be used for the development of a stadium for the San Diego Chargers, hotels and a new cruise ship terminal.

The proposal has been vehemently opposed by the Port of San Diego, and other bayfront users on the grounds that it threatens high-paying jobs and is incompatible with existing cargo operations.

"The reality is the types of uses this measure proposes cannot possibly coexist with a working cargo facility," said Michael Bixler, chairman of the Board of Port Commissioners.

But Gallagher has said the project would preserve maritime freight operations.

"We would have not written this initiative if it was our intention to do away with marine freight," Gallagher told the City Council.

Gallagher was part of a private group that collected more than 34,000 valid signatures to get Proposition B on the Nov. 4 ballot.

The proposal has been rejected by the City Council, Mayor Jerry Sanders, every local member of Congress and the Navy.

Navy Secretary Donald Winter recently sent a letter to Rep. Duncan Hunter, R-El Cajon, saying the development of the 10th Avenue Marine Terminal was "incompatible" with its use as a strategic military port.

Winter wrote that the Navy is "heavily dependent" on the terminal.

"Over 50 percent of West Coast military support for Operation Iraqi Freedom has passed through this vital hub, which is ideally suited for rapid load outs of heavy equipment for military units associated with contingency operations," Winter said in the letter. "It is also used by various shipyards for maintenance availabilities and provides a critical link to domestic and international suppliers of raw materials, finished goods and equipment utilized by these shipyards."

"In short, the proposed development would have a significant impact on the terminal's operational utility and other essential fleet activities in the area," Winter continued.

If the initiative passes, the port would be forced within 60 days to enter into an agreement with a private developer to redevelop the 10th Avenue Marine Terminal. It's likely the only developer who would be ready to bid are those that proposed the project.