Aker Philadelphia Shipyard held a ceremonial "keel laying" Tuesday for the second of four product tankers for Crowley Maritime Corp. Keel laying is a tradition, signifying good fortune and safe travels, that marks the beginning of a ship's life, even though production began months before.

At the ceremony, coins were placed on a "keel block," which will be part of the engine room of the completed ship. The keel block was lowered in the building dock in South Philadelphia. Officials from Aker and Crowley were present to place the coins and sign the keel block.

Also Tuesday, shipyard workers began cutting the first steel plate for the fourth product tanker in the series with Crowley.

The ships, when completed in 2015 and 2016, will be 600 feet long and can carry 50,000 tons of crude oil or refined petroleum product.

"We now have all four product tankers we are building with Crowley under construction, in various stages, throughout the shipyard," said Aker Shipyard CEO Steinar Nerbovik. "Our workforce has grown, along with our backlog of work, and I look forward to completing these vessels and many more together."

- Linda Loyd