Low-profile boats could resupply the Marine Corps

US Coast Guard law enforcement crew intercepts a semi-submersible drug boat in the Eastern Pacific (USCG file image)

Posted on October 11, 2022 at 1:44 p.m. by


[By LtCol Brent Stricker, USMC]

The Marine Corps faces an intensified challenge of contested logistics as it employs its new concept of Expeditionary Forward Base Operations (EABO). EABO calls on the Marines to act as reserve forces using low-profile, highly mobile Expeditionary Advance Bases (EABs) that will likely be within the enemy’s Weapons Engagement Zone (WEZ). Supplying these bases will be challenging as their location is expected to change frequently and reliance on the conventional global supply chain may not be responsive in a contested environment. One possible solution is the use of unmanned or autonomous self-propelled semi-submersibles (SPSS) to provide logistical support. It is important to consider how SPSS will be classified under national and international law, and what rights and obligations will be imposed on them in times of peace and armed conflict.

SPSS features

Smuggling provided the impetus for the SPSS. During Prohibition, bootleggers used SPSS to transport liquor down the Mississippi River. Colombian drug traffickers have adopted this technology to facilitate the smuggling of cocaine. Employing naval architects, they built a variety of models. The SPSS or Low Profile Vehicle (LPV) has proven to be particularly useful because it has only a small profile above the water, making it difficult to detect visually or with radar. Newer versions of narco submarines have proven to exhibit significant range and seaworthiness, as evidenced by a recent transatlantic voyage from Brazil to Spain. Similar ships appeared in the Russian-Ukrainian conflict.

These inexpensive vessels and their unmanned variants can provide an effective solution to mitigate degraded logistics for EABO within the WEZ. They are difficult to locate and, if found, easily replaced by a fleet built by commercial shipyards. They can be built to size and in large numbers, controlled remotely or autonomously, and unloaded after grounding before being returned to a logistics hub for recharging. They could be transported to forward areas by amphibious assault ships and landing platform docks and deployed from well decks.

Combining efforts with the US Coast Guard as a red cell could yield lessons learned as they continually search for similar semi-submersibles. This collaboration could lead to better ship design to avoid detection and solve the problem of degraded logistics in the WEZ. These ships could provide a resilient and risky method of distributed resupply that would help reinforcement forces endure combat.

Legal implications

If the US Navy or US Marine Corps chooses to adopt an SSPS, it is important to determine how the ship will be classified. U.S. forces would claim sovereign immunity on the vessel in accordance with NAVADMIN 165/21 preventing it from being subject to “arrest, search and inspection by foreign authorities”. The United States Navy recognizes several types of immune sovereign vessels: warships designated as United States Ship (USS), auxiliary vessels known as United States Naval Ship (USNS), United States Coast Guard cutters United States (USCGC), DoD time charter vessels under the United States flag. vessels used exclusively in non-commercial service and small craft (e.g. Landing Craft Air Cushions (LCACs)). In the case of voyage charter vessels, the United States “generally claims only limited immunity from arrest or taxation.”

A US Navy SPSS used only for logistic support may be classified as an auxiliary vessel or a small craft. The Commander’s Handbook on the Law of Naval Operations (Commander’s Handbook) defines an auxiliary vessel as “vessels, other than warships, which are owned or are under the exclusive control of the armed forces ‘operated’ solely in government non-commercial service “. Exclusive state ownership or control for non-commercial purposes confers sovereign immunity in accordance with Article 32 of UNCLOS and Article 9 of the Convention on the High Seas. or land, are also the sovereign property of the United States.

In 2022, the United States Navy deployed four unmanned surface ships in RIMPAC 2022. Task Force 59 also used unmanned ships to experiment with distributed maritime operations in the Fifth Fleet area of ​​operations. Both NAVADMIN 165/21 and the Commander’s Handbook recognize the sovereignty of unmanned ships that are remotely commanded and crewed.

As nations clash in the gray area below actual armed conflict, SPSS will have to operate in accordance with the international law of the sea. If designated as a ship, vessel or craft, SPSS will have to comply with the Regulations on Collisions (COLREGS) designed to ensure safe navigation in times of peace. The word “vessel” includes “any description of craft, including craft without displacement, [Wing in Ground] WIG boats and seaplanes, used or likely to be used as a means of transport on water. These regulations, also known as the COLREGS of 1972, were adopted as United States law (see 28 UST 3459, 33 USC § 1601–1608, and 33 CFR part 81). Section 1139 of the United States Navy Regulations of 1990 requires that collision regulations be observed by United States Navy vessels. The US Coast Guard implements the Collision Regulations as part of its Navigation Rules for International and Inland Waters (COMDTM16672.2D). SPSS will not be exempt from these requirements on vessels.

The Collision Regulations are intended to maximize the safety of navigation. They require constant watch (rule 5), operation at safe speeds (rule 6) and the use of a series of lights and signals clearly marking vessels (rules 20 to 37). The rules of lights and signals clearly pose a challenge to stealth operation of an SPSS during armed conflict. The lighting requirements for an SPSS pose a problem in the definition of the vehicle. Rule 22 of the Collision Regulations establishes the lighting requirements for a vessel based on its size. Vessels 50 meters or more in length must use a masthead light visible from six miles and sidelights, a stern light, a towing light and a panoramic light visible up to three miles. Small vessels have similar lighting requirements with visibility limited to as little as one mile. Rule 22(d) allows an exception for “an inconspicuous, partially submerged vessel or towed object” requiring a single visible white light all around three miles. Regardless of how an SPSS is classified, visible light out to three miles goes against the stealth approach to logistics.

If there is an armed conflict, there is an argument that the Peacetime Collision Regulations no longer apply. The principle of lex specialis stipulates that specialized law will prevail over general law. If we consider the COLREGS as a law of general application governing the safety of navigation in time of peace, it no longer applies from the start of an armed conflict between the belligerents. It is superseded by the law of naval warfare. Neutral vessels are still entitled to the protections of the Collision Regulations as well as other belligerent obligations towards neutral vessels.

Neutral ships and aircraft may be excluded from an area of ​​operations based on a belligerent’s right to control the immediate area around naval operations. The immediate area refers to “the area in which hostilities are taking place or the belligerent forces are operating”. The Commander’s Handbook notes how this ability to control access or exclude neutral ships and aircraft from operational areas ensures the safety of neutrals and belligerents. It allows the belligerent to operate without interference from a neutral ship or aircraft. This right allows for the total exclusion of neutral vessels or aircraft as long as “another route of similar convenience remains open”. It should be noted that neutral ships would also likely avoid any belligerent areas due to skyrocketing insurance rates, as seen more recently in the Black Sea due to the Russian-Ukrainian conflict.


The Marine Corps and United States Navy could benefit from experimenting with using SPSS for resupply in contested environments. Utilizing a sufficient number of these low observable ships will help enable distributed logistics to expeditionary forward bases. It can also help the United States supply allies and embattled partners, such as crisis-ridden Taiwan, without having to risk dramatically more expensive submarine assets. While some legal implications and platform design issues remain, the capability’s potential is tangible.

Lt. Col. Brent Stricker, US Marine Corps, is Director of Expeditionary Operations and Military Professor of International Law at the Stockton Center for International Law, US Naval War College. The opinions presented are those of the author and do not necessarily reflect the policy or position of the US Marine Corps, US Navy, Naval War College or Department of Defense.

This article appears courtesy of CIMSEC and can be found in its original form here.

The views expressed here are those of the author and not necessarily those of The Maritime Executive.

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