March 4, 2021: In late 2020 South Korea decided to spend $458 million to purchase 110 M3 amphibious bridging and ferry vehicles. These are used to quickly create a floating bridge capable of moving tanks and the heaviest armored vehicles over a waterway. The South Korea M3 vehicles will all be delivered by 2025. These will be used to replace South Korean bridges damaged by a North Korean attack or to provide needed bridges if South Korea advances into North Korea.

The M3 is the latest improvement over truck mounted pontoon bridge equipment first developed during World War II and widely used ever since. Some pontoon systems used inflatable pontoons but these took more time to prepare and were more susceptible to damage. Russia designed the first self-propelled pontoon bridging system when it put the PMP Folding Float Bridge vehicles into service during the early 1960s. This demonstrated its capabilities during the 1973 Arab Israeli war when the Egyptians used PMP vehicles to quickly construct float bridges across the Suez Canal. This came as a surprise to the Israelis, who expected the Egyptians to use older systems that took longer to implement.

The U.S. was impressed by the PMP ever since it was introduced and in the early 1970s introduced an improved PMP called the IRB (Improved Ribbon Bridge) or SRB (Standard Ribbon Bridge) that used lighter pontoons and improved mechanical elements which enabled the SRB to be deployed faster than the PMP. The next evolution was the German M2/M3 system that had an amphibious truck carrying two aluminum pontoons and roadway planks that enabled more rapid float bridge construction. The M3 was an improved version of the 1970s M2.

The M3 was developed in the 1980s by the same German firm that created the M2. The end of the Cold War in 1991 halted work on the M3 but that effort was revived in the late 1990s and the M3 was in service by 1999. Five countries (Germany, Britain, Taiwan, Singapore and Brazil) bought it and now South Korea is joining that group.

What’s unique about the M3 is that it can be used to quickly form a bridge, but also used singly or with two or three linked together as a ferry. Each of the 4x4 M3 vehicles weighs 28 tons and looks like a large truck. The M3 has pontoons folded up when moving and deployed when used as a ferry or part of a bridge. When the pontoons are deployed each M3 is 6.5 meters (21 feet) wide and 11.6 meters (37 feet long).

In 2016 Germany and Britain used their M3s (30 of them) to form a 350-meter (1,100 foot) bridge over the Vistula River. This took 45 minutes and when the bridge was ready it could carry anything from hummers to the heaviest tanks. The M3 was first used in combat (by the British) during the 2003 invasion of Iraq. The river country of Iraq, like most of East Europe, has a lot of rivers and streams interfering with vehicle movement, especially if the existing bridges had been destroyed. The M3 was designed to deal with that and was used twice under fire, once as a ferry (one M3 and its pontoons can serve as a self-propelled ferry) and once as a bridge. Eight M3s can form a hundred-meter (320 foot) bridge in less than 40 minutes. The U.S. Army also used its SRB pontoon bridge systems in Iraq, although these took longer to build.

M3 bridging amphibious trucks are driven into the water and the pontoons flop over to form a flat deck. The trucks-cum-ferry boats can either be strung together to form a bridge or (as they were during the battle) be joined into smaller combinations of ferries.

The M3 vehicle can do up to 80 kilometers an hour on roads and travel 750 kilometers on internal fuel. In the water the M3 vehicle can move at up to 14 kilometers an hour and carry up to 70 tons of cargo or vehicles on its 6.5 meters wide and 11.6 meters long platform. The PMP and IRB systems carry the pontoon on trucks that are not amphibious.

Army engineers also have rapid bridging equipment to span non-water gaps. These take longer to deploy but have the advantage of more permanency and less vulnerability to weather or debris, which remain a hazard for float bridges.