Every deep-sea mining company’s planning documents contain a passage where the focus switches from robots to ships. It’s not a glamorous change. Investor decks are not written about it. However, it may prove to be more significant than anything occurring on the Clarion-Clipperton seafloor four kilometers below.
After a harvester scrapes polymetallic nodules off the abyssal plain, how do you actually transport them to an onshore refinery? This is an oddly difficult problem to solve despite its seemingly straightforward form. It sounds like a typical shipping inquiry that any port authority deals with on a daily basis. It isn’t. The industry is just starting to consider the implications of the fact that the vessel performing the work, now colloquially referred to as a STARS (Shuttle Transport and Resupply Ship), does not yet exist in any standardized form.
Imagine the arrangement. Above the mine site, a huge Production Support Vessel weighing about 100,000 tons pulls harvesters along a slow, pre-planned track at a speed of about half a knot. It must continue to crawl forward while dragging equipment across the seafloor below; unlike a typical ship, it cannot simply weathervane and point into the wind. In order to transport thousands of tons of wet, slurry-like nodule cargo without colliding, spilling, or stopping the ongoing mining operation, a second, smaller bulk carrier must pull alongside it or fall in behind it. Shuttle tankers offload floating production vessels in this type of operation, which is loosely borrowed from the oil and gas industry. However, a bulk carrier isn’t a tanker, and nodules aren’t oil, and the analogy breaks down after a certain point.
In general, there are two methods for carrying out this transfer. A wider weather window is provided by tandem offloading, with the STARS positioned astern of the PSV, but it necessitates almost constant repositioning because the larger vessel cannot remain motionless. Although side-by-side mooring, lines bridging the gap, fenders absorbing impact, and simultaneous refueling and crew swaps are beneficial, the risk of collisions increases and choppy seas have the potential to completely halt operations. Instead of selecting a single, perfect solution, engineers researching this seem to be forced to choose between two problematic options, which is rarely a comfortable situation for a sector looking to secure funding.
Observing this from outside the engineering rooms, it’s striking how little institutional guidance there is. Every tanker captain is familiar with the well-worn rulebook that OCIMF and SIGTTO published years ago regarding the transfer of petroleum and liquefied gas between ships at sea. For the dry bulk transfer of seabed minerals, there is nothing comparable. There are rumors that that standard may eventually be written by a new institute connected to ocean engineering research in Texas. Investors enjoy hearing the timeline “eventually.”
Considering how unglamorous this bottleneck is, it’s worthwhile. For years, deep-sea mining has made headlines about sediment plumes, biodiversity loss, and geopolitical competition for nickel and cobalt. Shipyards are hardly mentioned in any of that coverage. However, shipyard capacity and lead times are precisely the kind of routine limitation that subtly decides whether a project meets its first production date or delays by two years, as so many offshore energy projects have done.
Additionally, no one seems willing to talk about the insurance aspect in public. It is difficult to underwrite a vessel class without a defined regulatory category, and assets that are difficult to underwrite often result in project financing costs that are prohibitively high. It’s easy to envision a situation in which the harvester, metallurgy, and offtake agreements are completed, but everything comes to a standstill because no one constructed, insured, or classified the ship intended to transport the goods home.
Perhaps that settles itself quietly, as is often the case with maritime standards, which are created by committees that are never noticed by anyone outside the industry. Or perhaps STARS ships turn into the obvious chokepoint in a narrative that has primarily been presented as a struggle between environmentalists and mining corporations. In any case, it’s difficult to ignore the fact that this industry’s unsexy components—ships, fenders, and classification societies—may have just as much of an impact on its future as anything occurring on the ocean floor.
