by Mattia Micheli, SeaNewsEditor

In 2023 alone, the Panama Canal had 14080 transits, averaging 38 daily.

Navigating this impressive facility is possible thanks to a series of locks, but it necessitates knowledge of a few regulations, which are necessary for the security of the Canal officers, the seafarers, and the facility managers.

Vessel sizes

The canal is a man-made facility; for this reason, the passage is allowed only to vessels with specific dimensions, which fit through the locks. Before 2016, small vessels were allowed to go through the Panama Canal, but it has been expanded since then, increasing capacity and efficiency. Vessels currently meeting the new dimensions, known as “Neopanamax”, have:

• Length 289.65 meters or less
• Width 32.31 meters or less
• Height 57.91 meters or less

For organizational reasons, the Panama Canal Authority assigns the date for transiting the canal after verifying the vessel’s dimensions. If it is effectively “Panamax” or smaller, it is allowed to enter the locks. These procedures are necessary to avoid congestion at the Canal.

The fee depends on the vessel’s dimensions and includes the transit fee, an inspection fee, a border fee, and a deposit that will be returned if there is no damage during transit.

The fee is calculated based on the vessel's size, type, and cargo.

After the fees are paid, the Authority assigns a transit slot for when the vessel should be at the facility's main entrance.

Transit from The Caribbean to Gatun

A vessel must pass through three locks to travel from the Caribbean to the Pacific (and vice versa). The Miraflores lock, the Pedro Miguel lock on the Pacific side and the Gatun lock on the Atlantic side.

The first is the “Gatun Lock,” which connects the Caribbean Sea to Gatun Lake. It is the only one on the Atlantic side of the Canal. The other two, the locks of Miraflores and Pedro Miguel, are both on the Pacific side of the Canal.

They're all filled with water from Gatun Lake, an enormous artificial lake that extends for most of the Canal. The lake ensures a steady water supply when operating the Canal, which is why the water levels there could determine the number of transits.

When entering the lake, vessels are guided by “mulas”: small and powerful locomotives. Every vessel is then followed and preceded by two small but powerful tugboats.

Locks are necessary since the Gatun Lake sits 26 meters (85 feet) above sea level.

When a ship enters the canal from either ocean, it first passes through a lock chamber. Water is pumped into the chamber, lifting the ship to the level of Gatun Lake.

After crossing the lake, the ship proceeds through another set of locks. Water is drained from the lock chambers, lowering the ship back to sea level.

Locks in history

The ancient Egyptians likely used the first locks in the world, as they had a canal between the Nile River and the Indian Ocean. However, this has never been proven, and the first example of a lock was documented in China in the year 983 A.D., near the city of Nanyang, built under the rule of the Commissary of Transport Chaio Wei-Yo.

Other locks could be found in Medieval Europe, especially in the north (such as in Belgium or the Netherlands), but the “modern system” was invented only in 1497, thanks to Leonardo da Vinci.

The modern locks, projected in 1482 when Leonardo was a Ducal Engineer for the Duke of Milan, consist of two pools divided by a gate.

The vessel enters the first pool, and a gate is closed, separating it from the rest of the Canal. The second pool in front of the first, divided by another gate, communicates with the first one through small canals, acting like “communicating vessels.”

The weight of the ship in the first pool pushes down the water and, from the first pool, moves it in the second until they’re both on the same level. At this point, the gate between the two pools is opened.

The Exit on the Pacific side

Transiting the Panama Canal can take from 6 to 8 hours (depending on conditions such as the climate, the fog, or the water levels). For exit on the Pacific side, it will be necessary to pass another lock, the Pedro Miguel lock, which links Gatun Lake with the smaller Miraflores Lake.

The last lock, with the same name as the lake, divides finally the vessels from the Pacific Ocean. Going through this lock will allow communication with the other ocean, sailing close to the quarter of La Boca in Panama City. 

Panama Canal and climate change

The entire canal spans approximately 80 kilometres and has facilitated trade movement from the eastern hemisphere to the west since its opening in 1914.

Climate change has recently significantly affected ships' transit through the Canal. A severe drought in Central America led to a 40% reduction in traffic.

In the past year, the Panama Canal Authority has limited the number of vessels passing through, causing delays and disruptions to global trade.

However, rainfall in the area permitted the gradual increase of the draft levels, and the number of vessels allowed transit. Most recently, Canal raised the draft level to 15.24 m (50 ft) and the number of available slots to 36.

To know more about the history of the Panama Canal, read Anchored in History: The Panama Canal.