Materials Marvels: A strategic waterway

Materials World magazine
,
1 Jun 2018

A major part of global trade routes, the Panama Canal celebrated its centenary in 2014. However, the first attempt to build the canal failed. Kathryn Allen examines how the waterway, nevertheless, became a vital access point.

Cutting through one of the narrowest pieces of land separating the Pacific and Atlantic Oceans – more locally the Caribbean Sea – the Panama Canal is one of the most important waterways in the world. 

It shortens sea journeys between the east and west coasts of North America by about 15,000km, as ships would alternatively have to go round Cape Horn, South America, as well as shortening trade routes between Europe and the west coast of North and South America, and Oceania. Goods transported through the canal range from automotive vehicles and grains, to coal, petroleum products, and coke. 

The yearly transit of around 13,000–14,00 ships, with a daily average of 40 in 2016, is enabled by a system of locks, fed by water from the Gatún, Alajuela, and Miraflores lakes. 

Breaking ground 

Prior to the construction of the canal, in 1881 a French-financed private company, Compagnie Universelle du Canal Interocéanique – led by Ferdinand de Lesseps, who built the Suez Canal – attempted to build a sea-level canal across Panama, despite strong opposition from engineer Adolphe Godin de Lépinay, baron de Brusly. Lépinay instead proposed a lock-type canal, by damming Gatún and Miraflores lakes, but was ignored by de Lesseps. De Lesseps’ attempt failed due to a lack of knowledge of the local terrain, insufficient machinery, and widespread disease, including yellow fever and malaria, among workers.

Take two

The USA then attempted to buy the French company’s assets, with the intention of building the canal. However, negotiations with Colombia, of which Panama was then part of, failed. With Panama’s independence declared in 1903, the Panama Canal Zone was created, affording the USA jurisdiction of a strip of land 16km wide along the canal. The USA began work in 1904 with Chief Engineer John Frank Stevens proposing a lock-type canal – similar to the one favoured by Lépinay. 

This plan involved damming the Chagres River, creating the 32km-long Gatún Lake, which formed part of the canal’s path. 

Railroads, steam shovels, rock drills, and dynamite were used to excavate and relocate 73 million m3 of earth and rock along the canal’s route. Built by the USA, the Panama Canal was under the country’s control from its opening in 1914 until 1979, when jurisdiction passed to the Panama Canal Commission – a joint enterprise of the USA and the Republic of Panama – and then, in 1999, complete control passed to Panama. The Neutrality Treaty, 1979, saw the USA and Panama agree access for all countries and non-discriminatory tolls. 

After it opened in 1914, tolls were imposed on vessels based on cargo capacity and type. In exchange for acknowledging Panama’s independence, Colombia was excused from paying tolls on government-owned ships under the Thomson–Urrutia Treaty, 1914. 

Success at last

Ships enter the canal via Limon Bay from the Caribbean Sea, travelling up the 11km-long approach channel to Gatún Locks, where they are raised 26m to Gatún Lake. Crossing the lake, they reach the Culebra Cut, through which they pass to be lowered 9m at the Pedro Miguel Locks. They then pass through Lake Miraflores to the Miraflores Locks, which lowers them to sea level, and out to Panama Bay and the Pacific Ocean. 

The locks – with 300m-long, 33m-wide, 12m-deep chambers – are fed by the flow of water from nearby lakes. 

Electric motors in the lock walls drive the gates, which vary in height from 14–25m. Large vessels are towed through the locks using electric locomotives, but use their own power to navigate the rest of the canal. Breakwaters, built at both entrances to the canal, protect from sea surges and reduce silting. 

Panama’s substantial rainfall allows the canal to operate despite the vast amounts of water used each time a ship passes through. If size allows, multiple ships travelling in the same direction are moved through the locks at the same time. Water-saving basins were built for new locks later during expansion. 

However, by the end of the century, as marine traffic increased in number and size, the need for further modifications was clear. 

Getting bigger

An expansion programme began in 1991 to widen the Culebra Cut – also the Gaillard Cut – from 152m to 222m, to allow two Panamax ships – a term indicating the size limits for ships moving through the canal – to move through simultaneously. Due to their size – the maximum the locks could accommodate – they could previously only move one at a time through the cut. This project was completed in 2001. 

However, further expansion began in 2007 to increase capacity to meet rising demand. This project involved widening and deepening the Pacific and Atlantic canal entrances, building new locks at both ends of the canal – the Third Set of Locks project – as well as expanding the Gatún Lake navigational channel, deepening the Culebra Cut, and building a new 6.1km Pacific Access Channel. The overall project cost US$5.25bln.  

Both the Pacific and Atlantic channel entrances were widened to a minimum of 225m, with the Pacific entrance deepened to 15.5m below the mean low water level of spring tides. The Atlantic entrance also saw the access channel to the new locks widened to 218m.

The project, which began in 2009, involved constructing two locks – one southeast of the Miraflores Locks and one east of the Gatún Locks – each with three chambers 21m wider and 5.5m deeper than the original ones. Water-saving basins – approximately 70m wide by 5.5m deep – at each lock allow 60% of the water used in each transit to be reused. 

Construction of the new locks involved the use of reinforced steel and around 4.4 million m3 of concrete per lock complex. To support the overall expansion project, two concrete plants operated 24 hours a day, six days a week, with some days seeing 8,000 tonnes of aggregate – including rock and fine sand – transported to the site for various concrete mixes. Basalt, for use in the concrete, was quarried onsite. The expansion project was completed two years after the canal’s 100-year anniversary, in 2014.

Not big enough 

In April 2018, the Panama Canal Authority also reported the successful transit of three liquefied natural gas (LNG) vessels through its new locks. These ships are classified as Neopanamax and must use the larger, new locks. According to the Authority, LNG vessels from the USA were, for the first time in 2016, able to move natural gas to Asia at competitive prices, having previously been unable to use the canal due to their size. 

Demand from the LNG sector is increasing, with a weekly average of five vessels transiting the canal. Panama Canal Authority Administrator Jorge L Quijano commented, ‘As exports from the USA increase, LNG transits could increase by 50% by as early as September [2018].’

However, the success of the expansion project, and ability of the canal to cope with increasing LNG shipments, is debated. A paper, Panama Canal and LNG: Congestion Ahead?, written by Howard Rogers, Chairman of the Natural Gas Research Programme and Senior Research Fellow, Oxford Institute for Energy Studies, UK, claims that, ‘The recent expansion of the canal capacity has not been without problems and LNG carriers are but one of many vessel types using the facility. The prospect of the Panama Canal becoming a bottleneck for LNG supply from Atlantic basin to Asian markets is therefore a very real possibility.’ The paper predicts that, even with two LNG slots per day, this bottleneck could occur in the early 2020s. 

Despite this, in March 2018 the Authority announced it had transited its 3,000th Neopanamax vessel – a containership measuring 300m in length and 48m in width. Of this Neopanamax traffic, 10% were LNG vessels.