The Two-Tier Sea: Why Shipping Fragmentation Is the Real Geopolitical Risk

The sea is no longer a commons

Eighty percent of global trade moves by ship. That number has been true for decades — a fact so familiar it barely registers. What is changing, and fast, is that the ocean is no longer a single legal and commercial space. It is being partitioned into two regimes: one governed by international rules, standard insurance, and transparency frameworks, and another operating in the shadows, outside those systems entirely.

The Consultative Shipping Group (CSG), an informal coalition of maritime authorities from 18 countries, issued a stark warning this week. Geopolitical pressures on shipping are not episodic shocks that recede, the group said. They are signals of a structural shift. The Strait of Hormuz, through which roughly 20 million barrels of oil per day flow, has become a chokepoint of disruption rather than a reliable artery. Blockades, fighting, and retaliatory measures have turned a waterway into a lever of economic coercion.

The consequence is not just higher freight costs. It is the slow unmaking of a system that has underwritten postwar prosperity.

Who builds the parallel system

The CSG did not name names, but the architecture of the shadow fleet is well known to anyone who follows energy flows. Hundreds of vessels — aged tankers and bulk carriers, many older than 20 years — operate without protection and indemnity insurance, without transparent beneficial ownership, and without adherence to international safety and environmental standards. These ships carry sanctioned cargo: Russian crude, Iranian petroleum, Venezuelan refined products, and goods routed through third countries to obscure their origin.

The mechanism is not subtle. When a major insurer declines to cover a vessel, a secondary market emerges. Flags of convenience multiply. Ship-to-ship transfers in international waters erase paper trails. The cargo arrives. The rules do not.

This is not a marginal phenomenon. The shadow fleet handles a significant share of the world’s sanctioned energy trade — estimates by independent analysts place it in the range of several million barrels of oil per day. That volume is not incidental to the global market. It sets prices. It creates parallel supply chains that run on different legal and moral premises.

Who wins, who loses

The immediate winners are states and traders who benefit from circumventing sanctions. Iran and Russia gain revenue streams that would otherwise dry up. Certain neutral shipping nations find themselves positioned as intermediaries — providing vessels, insurance alternatives, and logistical pathways that Western firms cannot or will not use. There is money to be made in opacity.

The losers are harder to pinpoint precisely because the damage is cumulative rather than dramatic. Cargo owners who rely on predictable shipping lanes face rising insurance premiums and longer transit times. Consumers pay more for goods whose supply chains have grown thicker with risk. And the rule-abiding segment of the shipping industry — the vast majority — operates under constraints that its shadow competitors do not. This is not competition. It is a system layered on top of another system, with different rules and different enforcement.

Insurance markets are the canary. P&I clubs, which provide mutual protection and indemnity coverage to shipowners, have repeatedly warned that expanding sanctions and the growth of uninsured fleets create moral hazard and financial contagion. When a shadow fleet vessel spills oil or suffers a catastrophic failure, there is no insured party to compensate affected states or industries. The risk does not disappear. It externalizes.

The chokepoint calculus

The CSG specifically named the Strait of Hormuz. But the chokepoint logic applies across the board. The Malacca Strait, through which China imports most of its energy, is equally vulnerable. The Suez Canal, already stressed by Houthi attacks and reduced transit volumes, faces new pressures. The Bab el-Mandeb, the Bosporus, the Taiwan Strait — each represents a potential point of escalation where a single incident could reroute global supply chains overnight.

What makes the current moment different is that these chokepoints are no longer primarily geographic vulnerabilities. They are instruments of policy. States are increasingly willing to use maritime access as leverage — not just by threatening closure, but by creating the conditions of uncertainty that make commercial planning impossible.

China faces a particular contradiction. It is the largest user of global shipping by cargo volume and the largest importer of seaborne oil. Yet it also benefits from the parallel system: Russia has redirected enormous volumes of crude to Chinese buyers at discount, and Chinese shipping entities have expanded their role in sanctioned trade routes. Beijing walks a careful line — publicly advocating for open seas while quietly profiting from their fragmentation.

What happens next

The CSG called on maritime nations to enforce existing international rules across jurisdictions and support common standards. That is correct advice. But the group’s statement also reveals the central problem: there is no coherent political strategy behind the warning.

The United States has expanded sanctions regimes that necessarily drive trade underground. European nations are divided on how aggressively to enforce those sanctions. Gulf states navigate between Washington and Tehran with pragmatic nonchalance. India and other non-aligned shipping nations treat sanctions as commercial considerations rather than moral imperatives.

Without a coordinated response, the two-tier system will deepen. Insurance premiums will rise further. Shadow fleet activity will normalize rather than recede. Chokepoint disruptions will become expected rather than exceptional.

The CSG’s most important line may be the smallest: “Shipping routes are increasingly instruments of leverage and risk.” That sentence describes a world in which the open sea is no longer open. The question is whether the powers that shaped the current order are willing to invest politically in restoring it — or whether they will accept, grudgingly, a fracturing maritime system as the cost of geopolitical competition.