PANAMA CITY, Panama -- Huge yellow dump trucks resemble Tonka toys in a sand pile as they haul tons of rust-colored dirt and basalt rock from a 56-foot gash in the earth that will become a new access channel in the $5.25 billion expansion of the Panama Canal.

The trucks keep rumbling up muddy terraced slopes as a quick-moving storm blurs the horizon. The rain chases away workers pouring concrete for a mammoth set of locks that will lift super-size ships for their transit across the narrow Isthmus of Panama, but the crews are back in the pit as soon as the sun returns.

By April 2015, it will all be under water — ready for the ever-bigger vessels revolutionizing international trade. The expansion is expected to double the canal’s capacity.

The 2015 target is about six months behind schedule, but U.S. ports are still scrambling to ready their channels for so-called post-Panamax ships and some say they welcome the reprieve. At this point, Baltimore and Norfolk, Va. are the only ports along the Eastern Seaboard with channels deep enough to handle the vessels when they’re fully loaded.

Call it the race for deep water as ports up and down the East Coast, including PortMiami and Port Everglades, and along the Gulf of Mexico make plans to dredge their channels, shore up their docks or rustle up funding for renovations to receive the big ships. Many won’t be ready by the time water floods the new locks.

PortMiami in position to cash in

PortMiami is further along than most and is hoping that early advantage and its position as the first major U.S. port north of Panama will make it a preferred port of call for post-Panamax ships.

Latin American and Caribbean ports also are trying to figure out how to capitalize on the expansion.

As this new phase of canal construction nears completion with 13,000 people working around the clock, there is renewed interest in preserving the history of the old Panama Canal Zone as well as the legacy of those who worked and died building the canal.

While the 50-mile-long Panama Canal has provided a maritime shortcut between the Atlantic and Pacific for the past 98 years, it’s just about maxed out.

This year vessels from the four corners of the globe — car carriers from Japan, bulk carriers loaded with soybeans and wheat from the U.S. heartland, oil tankers, towering container ships carrying the output of Chinese factories to U.S. retailers — are expected to move a record 332 million tons of cargo through the waterway, said Jorge L. Quijano, chief executive of the Panama Canal Authority.

That’s only about 20 million tons short of the canal’s capacity, he said. The canal is also popular with cruise lines and dozens of cruise ships are being built that exceed the size limits of the current canal.

But the more immediate problem is that the huge cargo ships increasingly favored for trade with Asia are too wide, too long and too heavy for the current canal.

With a growing number of ships in the post-Panamax category — exceeding the specifications for the largest ship that can fit through the existing locks — the Panama Canal must expand or risk losing market share.

And post-Panamax vessels aren’t even the biggest on the high seas. Post-Panamax Plus ships, such as most U.S. tankers that carry liquefied natural gas bound for Asia, are five times too big for the Panama Canal.