The Panama Canal opened almost 100 years ago.It connects the Atlantic and Pacific oceans and reduces travel by about 13,000 kilometers and avoids the need for ships to sail around Cape Horn at the bottom of South America. Built from 1904 to 1914,the canal has seen annual traffic rise from about 1,000 ships early on to 14,702 ships in 2008.In total,over 815,000 ships have passed through the canal.It has been named one of the seven modern wonders of the world.More than forty ships pass through the canal each day. Now,a major expansion  project will permit more ships and bigger ships to pass through the canal.Jorge Quijano,the Panama Canal's executive vice president of engineering,says,"The present canal has a total capacity  of about 340 million tons a year.With the expansion we expect to double that." For years,shipbuilders limited the size of many ships so that they could pass through the Panama Canal.But now many shipping companies use bigger ships to transport more goods as a way to reduce costs.Mr.Quijano says the expansion project will allow many of these larger ships to use the canal. Workers are building the new locks  alongside the old ones,which will remain in use.The existing locks are 305 meters long and 33.5 meters wide.The new ones will be 427 meters long and 55 meters wide.They will be able to handle ships with drafts  of more than 15 meters.At present,ships can ride only 12 meters deep in the canal. Engineers could not make the new locks too big.Mr.Quijano says the plans have to balance the size of the locks with the cost for ships to use the canal. The cost of the expansion is estimated at more than five billion dollars.The new locks are set to open in time to celebrate the 100th anniversary of the Panama Canal. Why not make the new locks too big?
Because they will cost too much. Partly because of the cost for ships. Because there are not so many workers. Because engineers are against it.