It is truly remarkable that some of the biggest manufactured vehicles are ships. These enormous vessels can stretch over a quarter mile in length and stand hundreds of feet tall. While the normal ship length is under 500 feet, record-breaking ships test the limits of marine design. Building such massive ships is an achievement in planning, engineering, and teamwork.

The world’s largest ships currently in use are transport container ships approximately 400 meters (1312.34 ft) long and 60 meters wide. To put things into perspective, these mega-ships are considerably longer than famous landmarks like the Eiffel Tower or Empire State Building when laid end-to-end. The tallest ships rise higher above the water than the Niagara Falls. Undoubtedly, these giants of the seas represent the height of our ability to construct functional floating structures.

One important limitation on the size of a vessel is the size of the canals they must pass through during voyages (SF Fig. 8.6). Several major canals allow ships to pass between distant ocean basins. The Panama Canal connects the Atlantic and Pacific Ocean basins by cutting through a narrow strip of land in Panama. Before the Panama Canal was completed in 1914, ships traveling between Atlantic and Pacific Ocean basins needed to sail around the southern tip of South America. Similarly, the Suez Canal links the Mediterranean Sea and Red Sea. The Saint Lawrence Seaway links Montreal, Canada, to Lake Superior. The largest modern ships cannot pass through the Panama Canal. Only ships less than 295 meters (967.85 ft) in length and 32 meters in width can fit through the tightest parts of the canal.

Here are just some of the longest ships that have ever been in operation.

Mærsk McKinney Møller

The Mærsk McKinney Møller, at 400 meters (1312.34 ft) long, is among the world's longest ships. It is the first in Maersk's Triple E class, the company's most energy-efficient ships. The Triple E class is owned by A.P. Moller-Maersk and operated by Maersk Line. The Mærsk McKinney Møller is 59 meters wide and 73 meters high, with a cargo capacity of 18,000 twenty-foot equivalent units and a maximum cargo weight of 165,000 metric tons. Launched in February 2013 and christened in June 2013, up to 20 ships in this series have been ordered.

Emma Maersk

Another example of such a colossal ship is the Emma Maersk, measuring 396.85 meters (1302 ft) in length and 59.13 meters in width. The ship boasts impressive features to match its massive size. With a capacity of 15,000 TEU (20 ft equivalent unit) containers, it stands among the largest cargo carriers globally. To handle such an enormous cargo load, the ship is equipped with a Wärtsilä-Sulzer 14RTFLEX96-C diesel engine that generates 97,000 horsepower. This is the largest marine diesel engine ever constructed. When fully loaded, the Emma Maersk displaces 165,000 tons of water, equivalent to the weight of 300 blue whales. Surprisingly, this gigantic ship only requires a crew of 13, plus 5 supercargo workers to oversee cargo operations. Advanced automation makes this minimal crew possible.

Seawise Giant

The Seawise Giant, also known as the Jahre Viking, held the record for the longest ship in the world for over two decades. This massive supertanker measured an astounding 1,504 feet (458.42 m) in length and 226 feet (68.89 m) in width. When it was originally built in 1979 by Sumitomo Heavy Industries Ltd, it had a record-breaking capacity of 564,763 deadweight tonnage (DWT).

At the time, the Seawise Giant was the largest ship ever constructed. It served as an ultra-large crude carrier (ULCC), transporting oil between the Middle East and Europe. The enormous size allowed it to carry over 3 million barrels of crude oil in a single voyage.

The Seawise Giant held on to the record of the world's longest ship for over two decades between 1979 to 2004, until being surpassed by the Emma Maersk. After serving as an FSO, the historic vessel was sold for scrap in 2009, bringing an end to its reign as the largest ship on the oceans.

Prelude FLNG

The Prelude FLNG facility, operated by Shell, is one of the longest ship in service at 1,601 feet (487.98 m) in length. As a floating liquefied natural gas platform, it is also the largest offshore facility ever constructed.

The Prelude FLNG, built in South Korea, has an annual LNG production capacity of 3.6 million tons and can produce 5.3 million tons of liquids. It has been operating off the coast of Australia since 2017, with the aim of monetizing previously stranded natural gas resources.

TI Class supertankers

The TI Class supertankers, constructed in 2002 and 2003, are the largest double-hull oil tankers ever built. These vessels, measuring 1,247 feet (380.09 m) in length and with a deadweight tonnage of 441,893 long tons, carried up to 3.2 million barrels of oil each.

However, due to their massive size and the low demand for oil at the time, the TI Class supertankers were uneconomical to operate. This led to the scrapping of three out of the four vessels that were originally built. Their great size brought efficiencies in principle, but the weak economics in the oil shipping market at the time meant they could not be profitable, despite their record-breaking dimensions.

While briefly holding the record for size, the unsuccessful TI Class experiment showed that giant ships still need favorable market conditions to be practical. Their construction represents an ambitious push for economies of scale that exceeded practical demand. The event highlights the difficult balance in building mega-ships - they can enable great efficiencies but require the economics and infrastructure to match their scale.

CSCL Globe

The CSCL Globe, operated by China Shipping Container Lines, measures at 1,312 feet (399.9 m) in length. Launched in 2014, it was the first ship to exceed 400 meters (1312.34 ft) in length. With a carrying capacity of 19,100 TEU, the CSCL Globe is one of the largest container ships in terms of capacity. Its size and efficiency allow it to transport export goods from China to Europe in a single trip, providing a faster and more efficient route for China's export industry. The CSCL Globe's massive size gives it economies of scale, allowing each container to be shipped at a lower cost than on smaller vessels. This has supported China Shipping Container Lines' competitive advantage in the Asia-Europe container route.

Barzan LNG Carrier

One of the longest ships currently in operation is the Barzan LNG Carrier, a Qatari-owned LNG carrier measuring 1,215 feet (370.33 m) in length and 213 feet (64.92 m) in width. With a cargo capacity of 266,000 cubic meters, the Barzan specializes in transporting liquefied natural gas from Qatar's North Field to global markets.

Equipped with a reliquefaction system, the Barzan maximizes the amount of LNG that can be transported while reducing methane emissions. Its massive size allows it to achieve economies of scale and efficiently deliver large quantities of LNG around the world in a single trip. The Barzan exemplifies how LNG carriers have grown to unprecedented lengths in order to meet the rising global demand for natural gas.

Esso Atlantic

The Esso Atlantic, built in 1977, held the record as one of the longest ships in the world at 1,371 feet (417.88 m) in length. It served as an ultra large crude carrier for Exxon, transporting oil between the Middle East and Europe. As one of the largest ships sailing the seas, the Esso Atlantic garnered significant attention. During its time, it represented the cutting edge in shipbuilding and maritime engineering.

However, despite its massive size and capacity, the Esso Atlantic eventually became uneconomical to operate. With its operating costs high compared to newer vessels, the Esso Atlantic was taken out of service by Exxon in 1998. After over two decades as one of the longest ships ever built, the Esso Atlantic was eventually dismantled at a shipbreaking yard in India.

Pierre Guillaumat

The Pierre Guillaumat, which sailed from 1979 to 2003, held the record for the world's longest ship for over two decades. During this time, it transported crude oil between the Middle East and European ports. Measuring 1,320 feet (402.34 m) in length, the Pierre Guillaumat could carry a whopping 553,611 tons of cargo on each voyage across the seas.

Despite being such a mammoth of a vessel, the ship required a surprisingly small crew of just 44 for normal operations due to a high degree of automation on board.

After 24 years of service spanning from 1979 to 2003, the Pierre Guillaumat was scrapped. Advances in shipbuilding meant newer tankers were more efficient, and the ship had become too costly to run. The grand ship was eventually dismantled in India in 2003, closing the chapter on the world's longest ship for over two decades.

The world's biggest ships demonstrate incredible engineering and innovation in shipping. From container ships to oil tankers and LNG carriers, shipbuilders continue to push the boundaries of size and capacity. What could ship sizes reach next? Some expect container ships could eventually exceed 518.16m (1700 ft) long and 25,000 TEU capacity. LNG carriers and oil tankers will likely grow too. Shipping economics and port restrictions will determine how big ships can realistically become. One thing is certain - naval architects and marine engineers will keep innovating to build the largest ships the world has ever seen.