Background 

In my previous column, I had touched upon the term “Naval blockade.” Aim of this brief is to explain the complexities of implementing a Naval blockade in a narrow navigational strait for the reader to understand the complexity of the subject better.

Brief Explanation of a Naval Blockade 

Naval blockades are an act of war and are complexstrategic operations that involve significant operational,legal and economic challenges, with the aim to restrict maritime access to target nation’s coast and cripple its economy or military capability. Modern blockades are rarely total and focus on specific goods, requiring constant monitoring of high traffic areas and creating high risks of escalation. A blockade works by positioning warships and aircrafts/ Helicopters around an adversary ‘s coast. Submarines also can be deployed in open oceans to achieve the objective. In the West Asia context, the aim of the US Navy is to restrict tankers carrying crude oil leaving Iranian ports and vessels entering the ports to load cargo thus weakening their economy without a full-scaleinvasion.

Types of Blockades 

• Close Blockade – This is an operation involving highest risk to the blockading force as they operate continuously at sea near enemy coast, vulnerable to surface, underwater and air threats from the adversary. The current US implemented blockade can be classified as a close blockade. 

• Distant Blockade – A safer approach for the blockader is to implement a blockade at a distance from the objective area. This operation would be undertaken in an open ocean and require many units to implement the intent. Any blockade that the US Navy would attempt at the seaward entrance of the strait of Hormuz (Gulf of Oman/ Oman sea) would fall in this category.

• Loose Blockade – A close blockade that positions behind the horizon to bait the adversary into exiting the port with the aim of intercepting the target using the element of surprise. 

• Total Blockade – The most severe form designed to completely shut down all entry / exit to a region. 

• Paper Blockade- A blockade that is announced but not effectively enforced is referred to as a paper blockade which is invalid under international law,

How does a Blockade work? 

• • Establishment & Monitoring Naval forces establish patrol zones, deploying ships, Aircrafts/ Helicopters usingradars and other sensors, satellite imagery, and aerial surveillance to identify and monitor vessels in the area. 

  • Interdiction Blockading forces intercept, board and search incoming/ outgoing ships.

  • Enforcement Ships deemed to be violating the blockade are either turned back, boarded, or seized.

Strategic aims of a blockade 

• Economic warfare. Starve the adversary of critical resources (oil, food and essential goods) to paralyze their economy and livelihood.

• Military Restriction – Prevent supplies, troops and weapon systems from reaching the adversary.

• Psychological Pressure- Demoralize the adversary’s population and government by showcasing total isolation. 

• Strategic US aim for implementing blockade in Hormuz

The US intent is to sever Iranian oil exports and penalize Tehran for interfering with maritime traffic in the strait of Hormuz, following failed ceasefire negotiations.

• Control of Strait of Hormuz 

The strait of Hormuz is not controlled by a single entity: It is legally bordered by Iran and Oman, which hold sovereign rights over their coastal waters, but international law guarantees transit passage for global shipping. Under international law (UNCLOS- United Nations Conventions for Laws of the Sea) both Iran and Oman control up to 12 nm of sea room from their coastline. During this conflict, Iran has turned this shared maritime route into a controlled area by attempting to regulate and even charge tolls on vessels passing through the straits. 

• Maritime Exclusion Zone 

Maritime Exclusion Zone is closely linked to a blockade. As of April 2026, and as a counter to the US blockading Iranian ports, the strait of Hormuz is experiencing a severe, de facto maritime exclusion zone with Iranian forces restricting or blocking commercial ships from transiting through the strait of Hormuz in response to the US actions. This action is legally contentious under UNCLOS and Iran has imposed operational restrictions forcing vessels to follow alternate routes approved by the IRGC. 

Complexities of a Naval Blockade in Strait of Hormuz

Naval blockades are complex, high stakes maritime operations that function as a form of economic warfare. Their execution involves significant logistical, legal and operational challenges often subjected to intense international scrutiny and severe economic impacts on global shipping. 

Enforcement Challenges – Enforcement of a Naval blockade in strait of Hormuz implies severe operational, legal and economic complications. It requires huge manpower and resources. These waterways are crucial for global trade and restricting movement of ships leads to rapid escalation of conflicts , intense logistical challenges for the blockading force and major disruptions to the global energy supply .The current blockade in the strait of Hormuz face additional challenges of heavy maritime traffic where it is impossible to board, inspect and redirect every ship in such a manner that smooth movement of trade is not affected. The sheer volume of commercial traffic makes it nearly impossible to stop every vessel for investigation.

Dark fleet/ Ghost ship problem – Non cooperative vessels frequently use GNSS (Global Navigation Satellite System) spoofing, false port records, false cargo manifest, false vessel registration records and AIS (Automatic Identification System) blackouts to evade detection & identification. 

Asymmetry of Naval strength – An effective blockade is only feasible when the blockading power has a vastly superior Naval force compared to the opponent. In the current scenario, the US has a superior force undoubtedly,but this force is vulnerable to Mines, unmanned craft attacks, shore based Anti-ship missile batteries to name a few. Narrow straits allow defenders to use swarm tactics with small fast attack crafts which are difficult to counter. 

Limited Maneuvering Room – Blockading US force have limited space in the straits to maneuver increasing the danger of accidents due to the restricted sea room. 

Logistics difficulties – Sustenance of ships and crew at sea for long periods far from shore support makes the operation logistically complex.

Mine Warfare – The deployment of Naval mines ranging from contact based to advanced magnetic, acoustic,pressure & combinations makes detection difficult and presents severe danger to all ships. This threat can only be countered by specialized Mine countermeasures operations which is slow and time consuming.

International Law & Legal Risks 

Legality – A blockade must be formally declared,officially notified and applied with impartiality.

Neutrality Rights – Interdiction of neutral ships can create huge legal risks for ship owners as it leads to conflict with international freedom of navigation principles elaborated in UNCLOS. 

Humanitarian Concerns – Blockades that cause severe civilian starvation or violate humanitarian law (blockingfood / medical aid are regarded as illegal.

Global Economic impact 

Chokepoint sensitivity – Blockades in vital navigational straits such as Hormuz directly impact global energy supplies and disrupt the movement of vital cargo such as fertilizers and essential goods.

Rising Freight Costs – Insurance premiums often spike to prohibitive levels due to war risk insurance and commercial ships are forced to take longer routes thereby increasing fuel consumption resulting in high freight costs.

Supply chain Disruptions – Even a partial blockade can cause severe port congestion and threaten global food and economic security to the region.

Limitations of Effectiveness of Blockade 

• Effectiveness
  Blockades rarely produce immediate results and are often used as tools for gradual economic pressure rather than swift military victory.

• Substitution by Alternate modes
  Targeted nations find ways to import / export through alternate sources by land routes limiting total isolation the blockade seeks. 

• Might is right Scenario 

If the enforcing power is not bound by or ignores UNCLOS, the enforcement becomes a geopolitical contest reducing the effectiveness of international law and third-party intervention/ mediation.

• Other Factors 

US has embarked this conflict with multiple aims and objectives viz destroying Iran ‘s nuclear infrastructure and enrichment capability, seizing Uranium stockpile, capping their nuclear program, destroying missiles / Drone stocks and the ability to replenish them and cutting off Iran ‘s support to proxy groups in the region. Although these facets may not directly impact the effectiveness of the blockade, but indirectly it may determine the duration of the blockade. Also, execution of multiple aims in a conflict may stretch the availability of resources and logistics that is paramount to achieving an effective blockade.

Effectiveness of blockade is also indirectly linked to the third front war between Israel and Lebanon, total lack of international support to the US operations and the lack of convergence on the terms/conditions projected by US and Iran in peace negotiations. 

Conclusion 

The US blockade on Iranian ports is aimed to curb Iranian energy exports thereby crippling its economy to force Iran back to the negotiating table. While the US Navy has successfully intercepted vessels and maintained a firm presence, success remains uncertain as the blockade hinges on high stakes with global ramifications which could lead to a long-term war of attrition. Iran has retaliated by closing the straits and attempting to maintain its own control over ship traffic. The current situation involves significant military risks with potential for further escalation unless and until both sides agree to reach a consensus during future peace negotiations.