Rio Tinto Takes Delivery of Record-Setting Self-Unloader Built by CSSC
A newly built self-unloader designed to support the African ore operations of Rio Tinto named Wontanara was delivered on July 21 by its Chinese builders. China State Shipbuilding Corp. (CSSC) is calling the new vessel “the king of self-unloading ships” due to three records it reports the ship achieved.
CSSC says the class of five ships will be the world’s largest shallow-water transshipment self-unloaders (by deadweight) as well as the fastest self-unloader in terms of discharge speed among specialized vessels. They are also the first bidirectional self-unloaders in their tonnage class. The vessels were specifically designed for Rio Tinto’s operations at the Simandou iron ore project in Guinea, in West Africa.
The project is being developed in partnership with China and will be a world-class exporter of high-quality ore. A Chinese consortium will operate two of the four mines, with the other two controlled by Rio Tinto. Operations began in late 2025 at the site and have been ramping up this spring, with reports saying the total deposit is valued at more than $24 billion.
Wontanara is said to be the largest and fastest unloader of its kind (CSSC)
Among the challenges at the site is the shallow water position near the mines. The solution is the fleet of five vessels that will load ore and transship it to the larger ocean-going ore carriers that will anchor offshore. Each of the five self-loaders will be 41,800 dwt and 215 meters (705 feet) in length with a capacity for 29,000 cubic meters of ore. The vessels will operate with a draft of just 14.5 meters (47.5 feet) versus a typical large ore carrier, which would have a draft of approximately 18 meters (60 feet) or greater.
The new vessels reportedly also set a speed record for the rate of discharge. Each will move 12,000 tons of ore per hour, which CSSC claims is a 71 percent increase in efficiency. It says the previous record was 7,000 tons per hour, held by another vessel that it refitted in 2023.
With each of the five vessels able to transport 41,800 tons of cargo and their discharge speed, it claims the five vessels will be able to fully load a 200,000-ton ocean-going bulk carrier within 24 hours.
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To increase the maneuverability of the vessels, they can fully operate in either direction. They are powered by a diesel-electric propulsion system. It also features a high level of automation and can be operated with a small number of crew.
Construction on the Wontanara began in May 2025 at the Yangzhou shipyard, and the vessel was completed in just 14 months. The ship underwent 12 days of sea trials in late June and early July before today’s delivery. CSSC reports the second vessel of the class is scheduled to be delivered in October. It launched the two vessels of the class in May and June of this year. All five ships will be delivered before the middle of 2027.
