In the late 2000s, single-hulled tankers were being phased out in favor of double-hull designs, and several bulker owners bought obsolete single-hull VLCCs for conversion to ore carriers. The demand for Capesize bulkers was high at the time, and the conversions were common enough that Steamship Mutual published a guide to the process. Typically, these converted VLCCs were fitted to utilize the center tanks as ore cargo holds, with the side tanks left empty or used for ballast.
The converted VLOC class has been implicated in several safety incidents, notably the loss of the converted VLOC Stellar Daisy in 2017. The Republic of the Marshall Islands Maritime Administrator (Stellar Daisy's flag administration) concluded that the likely cause of her sinking was a catastrophic structural failure of the ship’s hull, resulting in loss of buoyancy and uncontrolled flooding. The administrator determined that the strength of the ship’s structure may have been compromised over time due to material fatigue, corrosion, structural defects and multi-port loading, in addition to weather effects. In inspections conducted after the vessel's loss, several other converted VLOCs in the same operator's fleet were found to have structural issues.
“The tragic Stellar Daisy accident brought the safety aspect of VLOCs into question. Now, three years on, three out of five VLOCs are no longer in operation as their long-term charters have now expired," said BIMCO Chief Shipping Analyst Peter Sand. “Going forward, the obsolete VLOCs will be phased out of the market and replaced with technologically superior and more reliable ships."
BIMCO says that once these aging converted vessels come off charter, they are no longer economically competitive due to their high maintenance costs. There are only 28 VLOCs remaining in service, according to the association, and eight of them are laid up. All are nearing the average demolition age and have been superseded in capability by larger, newer Valemaxes.