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Heavy Lift Ships: Moving Things That Should Be Too Big To Move

In 2005, the US government and its private contractors finished assembling a floating radar system called Sea-Based X-Band Radar in Ingleside, Texas. One problem, though, the system was designed for use in the Pacific with its initial deployment for testing in Pearl Harbor, Hawaii, 15,000 miles away by a sea journey that would require it going all the way around South America. That’s over 24,000 kilometers, nearly three-quarters the circumference of the Earth.

Plus, the fully assembled system weighed roughly 50,000 short tons, or 45 million kilograms. For reference, the Boeing 747-400 passenger plane has a takeoff weight of about 440 tons. How exactly do you transport something heavier than 100 jumbo jets to the other side of the world?

The job fell to the MV Blue Marlin, a semi-submersible heavy-lift ship owned and operated at the time by the Dutch company Dockwise. After carrying the massive floating radar system through the Strait of Magellan in December 2005, it reached Pearl Harbor on January 9, 2006.

Blue Marlin has carried other impressive cargo as well. After the American naval guided missile destroyer USS Cole was damaged in a terrorist bombing in 2000, Blue Marlin carried it from Aden, Yemen, back home to Mississppi. In 2004, it carried Thunder Horse, an oil production rig weighing a whopping 60,000 metric tonnes, from its assembly point in South Korea to the Gulf of Mexico where it now operates.    

And Blue Marlin is not the only heavy-lift ship out there, nor is it even the largest or most powerful. These impressive vessels are essential parts of the world economy, transporting massive industrial facilities and other ships that would otherwise be immovable. But how do they do it?


The ancestor of modern heavy-lift ships is often considered to be the SS Lichtenfels, built by Deutsche Schiff- und Maschinenbau Aktiengesellschaft, also known as Deschimag, in Bremen, Germany, in 1929 for the German shipping company DDG Hansa. It was designed to transport fully assembled locomotive engines from Europe to India and had a total deadweight of 11,000 metric tonnes, meaning this was the maximum amount of total weight it could carry.

The SS Lichtenfels was roughly 160 meters in length, or 525 feet, almost the length of two football fields—European or American, take your pick. It used a three-cylinder steam engine to power a single propeller at 5,100 PSi, rotating it at 74 rpm. This was enough to push the ship up to 13.7 knots, or almost 16 miles per hour, about the same speed as modern heavy-lift ships.

Perhaps the most innovative part of the Lichtenfels were its booms, the cranes used to load the locomotives and other cargo onto the ship, eliminating the need for cranes on the docks. The main boom weighed 120 metric tonnes, or nearly 265,000 pounds, but there were 21 in total, including one weighing 30 metric tonnes, another 15, and 18 booms weighing 5 metric tonnes.

Locomotives weren’t the only thing Lichtenfels carried, though. Elephants from India were another common part of the cargo. Plus, the ship could carry a crew of 74 as well as 12 human passengers.

During World War II, Nazi Germany sent the SS Lichtenfels to the Red Sea along with a number of other merchant marine ships. In 1941 as the British threatened to retake the area, Germany scuttled it to blockade Massawa Harbor in Eritrea. It was ultimately raised in 1950 and used for scrap.

Since then, there has been considerable innovation and advancement in the heavy-lift-ship design. Specifically, heavy-lift ships are now divided into four different categories.


Project cargo carriers are arguably the most similar to the original Lichtenfels. These ships are not especially different from standard cargo ships, but they’re designed to be able to handle loads and cargo that may not fit into the standard intermodal containers that can be easily stacked and arranged on other ships. This is termed “project cargo” and usually means large goods or machinery important to heavy industry.

Most notably, since a project cargo carrier’s cargo doesn’t fit into intermodal containers, dock cranes are usually incapable of lifting it and placing it on the ship. Therefore, these heavy-lift ships have their own cranes, one on either end, which move the project cargo from the dock onto the ship’s low, flat deck.

The two cranes must be located on the same side of the ship, either port or starboard, to adequately lift the cargo, but if you’ve ever tried to lift a cooler into your canoe, you know just how unstable this can make a boat. As a result, project cargo carriers have to have elaborate ballast systems that must be operated with precision to balance the ship, ultimately allowing the cranes to lift with four times the power of standard deck cranes.


Open deck cargo ships are perhaps the simplest type of heavy-lift ship, but that doesn’t mean they aren’t capable of hauling massive cargo. They feature long, low, flat decks of up to 300 meters, nearly 1,000 feet, bookended by the ship’s fore and stern but without any walls on either side. This allows them to carry cargo that’s too wide to fit on standard cargo ships like large cranes, industrial vehicles, construction equipment, and even other boats like yachts and ferries.

At the bow of the ship, there is a tall superstructure that houses just about all the ship’s operations including the bridge, galley and cabins. The main deck is then much lower down closer to the water level. Because it’s so low but must also support such heavy cargo, this deck must be supported from beneath by a tough web of metal framing.

Additionally, the deck must be strong enough to support the ballast tanks and the marine shafts which run from the engines to the propellers. Open deck cargo ships have a kind of catch-22 in that the superstructure at the ship’s bow provides more room for the engines, but this makes the marine shafts much longer and more prone to vibration, which could damage the deck or its cargo. In other words, the metal framing of the main deck must be strong enough to support the engines or the vibrations of the marine shafts, one or the other.

The other primary obstacle for open deck cargo ships is loading and unloading. Considering their cargo often includes cranes themselves, they can’t be loaded or unloaded with dock booms. Instead, the cargo is rolled, towed or otherwise slid onto the deck, which must be lined up level with the dock. 

But, of course, these massive ships weigh tens of thousands of tons and can’t just be floated up to the dock. Instead, elaborate tethering systems are used like pad-eyes, and some of the ships have ramps that help cargo be rolled on and off.


As the name suggests, a dock ship is essentially a floating, mobile dock. There’s a superstructure at the bow that has the bridge and crew quarters while the rest is a submersible deck with walls on the port and starboard sides.

The main deck can be lowered down into the sea so that water floods it, held in by the walls on either side. Cargo can then be floated in through the opening in the stern. Once inside the walls of the dock ship, the deck is raised by pumping out its ballast water and removing the water on the deck.

As you can probably guess, dock ships are primarily used for moving other marine vessels. Specifically, they’re used to move, repair and maintain other boats, even allowing access to parts that would normally be underwater like propellers and marine shafts. Not only are they considerably cheaper than dry docks on land, but they’re mobile. If you’re a damaged ship, you don’t have to come to the dock, it will come to you.


Semi-submersible vessels are what many have come to think of when they imagine heavy-lift ships. They’re shaped similarly to open deck cargo ships with a tall superstructure at the bow and a long, low, flat deck behind. However, unlike open deck cargo ships, their main decks can be submerged below the surface of the water.

Using advanced ballast systems, semi-submersible vessels take in water to increase their draft and sink into the sea. Once the main deck is below the surface, the cargo is floated into position over it. Then pumps remove the ballast water, causing the ship to float back up, lifting the cargo with it.

These semi-submersible heavy-lift ships are used to transport massive structures that you’d otherwise think would have to be built on location. For example, they often carry oil rigs, floating factories, other cargo or naval ships, and things like the Sea-Based X-band Radar.

The previously mentioned MV Blue Marlin is an example of a semi-submersible heavy-lift ship, and with a total deadweight of over 76,000 metric tonnes and length of 225 meters, it was for a time the world’s largest semi-submersible ship. However, in 2011, the Blue Marlin’s owners, the Dutch shipping company Dockwise Shipping BV decided they needed a bigger boat and ordered Vanguard, which has been the current title holder since its launch in 2012.


Vanguard is the industry leader and arguably the most technologically advanced heavy-lift ship to date. It has a displacement—basically the weight of a ship—of over 91,000 metric tonnes, and has a total deadweight carrying capacity of nearly 117,000 metric tonnes. That’s more than 10 times what its ancestor the SS Lichtenfels could carry. At 275 meters or 902 feet long, its deck is 70% larger than Blue Marlin’s. 

Vanguard produces 28,500 kilowatts of total power. That’s over 38,000 horsepower, about the power of 75 semi-truck engines. This is provided by two Wartsila engines running at 8,700 kilowatts each and two more running at 4,350 kilowatts each turning two propellers with controlled pitch that can move the ship at upwards of 14.5 knots, or almost 17 miles per hour. It also has two 3,000-kilowatt retractable azimuth thrusters and one 3,000-kilowatt bow thruster.

Vanguard also has 50% more lifting capacity than the Blue Marlin thanks to a powerful ballasting system. The four main ballast pumps can push out 5,300 cubic meters per hour. That’s nearly 1.5 million gallons or well over two Olympic swimming pools. Another pump pushes out 1,500 cubic meters per hour while two stripping pumps eliminate 400 cubic meters per hour and two stripping ejectors eliminate 300 cubic meters per hour.

This lifting capacity is helping Vanguard set records. In 2020 it made news when it transported FPSO P70, a floating production storage and offloading unit weighing over 91,000 tons from Qingdao, China, to Rio de Janeiro, Brazil, via the Cape of Good Hope in South Africa. An FPSO is a massive vessel similar to an oil tanker that can produce, store and transport oil and other hydrocarbons. It was the heaviest cargo ever carried by a semi-submersible heavy-lift ship.  

Vanguard was designed by Dockwise and Finnish company Deltamarin, then built by Hyundai Heavy Industries in South Korea. It cost roughly $240 million and was funded by the Dutch bank ABN AMRO, the Royal Bank of Scotland and Deutsche Bank.

Then in 2013, the Dutch company Royal Boskalis Westminster NV acquired Dockwise, eventually putting their logos and name on the now BOKA Vanguard. Not only that, but they decided they were going to take heavy lifting to the next level. In 2014, they began looking into the possibility of building an even bigger vessel, one that would be capable of carrying Vanguard itself. A ship to carry the ship that carries ships.

In the meantime, Vanguard continues operating in Boskalis’s fleet of 11 semi-submersible heavy-lift ships that also includes Blue Marlin and its sister Black Marlin. Before it gets dethroned, let’s hope it finally finds a cargo heavy enough to max out that unbelievable 117,000 metric tonnes of deadweight carrying power.


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