I've watched the film The Trouble with Pirates [IMDb] and the one thing that is most surprising to me is that those captured ships offered no resistance and were virtually defenseless. The pirate ships are small boats that would be easily sunk with a single torpedo or a heavy machine gun.

The galleons were heavily armed. Why are contemporary cargo ships travelling unarmed in such dangerous regions? Are there any regulations in international law forbidding the use of heavy weapons in self-defense for private ship operators?

What legal consequences would have arming the cargo ships with torpedoes and machine guns and sinking approaching pirate boats?

  • I think this is about law more than politics. However you might look at this report. It seems machine guns are a perfectly adequate deterrent and heavier weapons probably unnecessary. Commented Oct 27, 2013 at 19:08
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    This question appears to be off-topic because it is about law rather than politics. Commented Oct 27, 2013 at 19:08
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    @DJClayworth international law IS a subject of political studies, so the question certainly is on topic. Commented Oct 27, 2013 at 20:11
  • It's up to the flag state of the ship to supply some kind of police (not military) to defend the ship. I don't see e.g. Panama doing that. Commented Oct 30, 2013 at 22:48
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    A torpedo or missile and everything that goes with it (fire control system, space in the hull, personnel, maintenance) is actually very very expensive. Much more than paying some insurance premium and/or ransom from time to time. Even a an actual naval gun is expensive (and exports are severely restricted). OTOH, I think there have occasionally been armed guards on ships, but that's not necessarily very effective either.
    – Relaxed
    Commented Apr 18, 2016 at 17:34

4 Answers 4


What actions are legal against pirates for private ships?

It depends on the maritime laws of the flag state and whether the ship is in international or national waters at the time of the incident. Hence the answer is highly variable depending on the exactly which marine treaties the flag state has signed and ratified.

However the doctrine of universal jurisdiction does apply against certain marine crimes such as piracy. Specifically, since as a pirate is considered hostes humani generis (enemy of the human race), a merchant ship could kill pirates with impunity and probably pass any legal challenges in their next port of call.

But merchant ships usually do not carry lethal ordinance for several reasons:

  • Historically a heavily armed merchant ship crosses the line into a warship or privateer of the flag states. Essentially a part of the nation's auxiliary navy and treated as such.
  • Some countries and ports of call will consider a heavily armed merchant ship to be gun-running. Which is more common than you might think.
  • Lethal ordinance can and often does cause conflict escalation; to an extent that only the pirates can afford.

Why are contemporary cargo ships travelling unarmed in such dangerous regions?

Saves fuel + the reasons for being unarmed. Besides at its height, the dangerous region was very large as the speed boats usually docked with ocean-going support ships instead of the land ports; extending the effective range (and requiring a greater capital investment by the pirates to pay off).

Are there any regulations in international law forbidding using heavy weapons in self-defense for private ship operators?

International law? We don't actually have much true international law yet. Simply conventions and treaties signed by nation states. As such, the exact constraints depends on either the flag state or whatever any nation feels like enforcing on merchant ships in international waters.

What legal consequences would have arming the cargo ships in torpedoes and machine guns and sinking approaching pirate boats?

As above. Specific consequences depend on specifics, such as:

  • Where the incident occurred.
  • Whether it occurred wholly or in part in international or national waters; or multiple potentially overlapping national waters.
  • The flag-state of ship.
  • The nationality of the company owning the ship.
  • The nationality of each crew member, especially the captain.
  • The port that the ship is currently docked at during trial.
  • The country the trial actually occurs in.
  • The state of belligerency between any of the nations or nationalities listed above.
  • The nature of business that the merchant ship was undertaking. Whether the merchant ship itself was hostis humani generis.

And the list goes on.

A political aspect to this question:

Somali piracy was initially a reaction to fish poaching inside Somali national waters due to the collapse the Somali government and coast guard. The recent history of Somalia is a rich vein (of deeply depressing) political fundamentals with the normal buffer of diplomacy stripped away. That is, small fish (fishermen) eaten by bigger fish (poachers) eaten by bigger fish (pirates) eaten by bigger fish (foreign navies). The smallest fish eating actual fish due to the collapse of inland agriculture.

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    Actual examples of the court cases would make this a truly excellent answer, but +1 nonetheless.
    – user4012
    Commented Oct 28, 2013 at 15:42
  • Having re-read the answer, one part stands out as extremely weak - you gave zero evidence that "Conflict escalation" is an actual reason and concern for not arming.
    – user4012
    Commented Aug 11, 2014 at 13:52
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    @DVK Opinions on the role of conflict escalation in the re-allocation of opportunity costs of increased armament tends to break along classical party lines especially in the US due to its bitter gun debate. As such, exploration the topic requires a full Q&A itself. I've left the conflict escalation in as a reason, as the pirates are parsimonious and wouldn't pro-actively purchase advanced weapons and armor above and beyond what is readily available in Somalia unless they had to. Commented Oct 22, 2014 at 0:56
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    @sjoerd Google found it easy. hakaimagazine.com/news/foreign-fleets-plundered-somalias-fish As for the causal link - people of a specific country don't wake up one morning and say "hey I'm going try my hand at piracy". The first pirates were fishermen armed to take back stolen fish within their EEZ. Expansion of piracy happened later; to chase more lucrative ships. Commented Mar 18, 2019 at 14:43
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    @sjoerd It's not my job to convince you; this isn't high school debating. Post an alternate answer if you have one. Try this article on for size: theguardian.com/world/2015/oct/31/… You can see the causal link reforced forwards and backwards. It got so bad, Somalia basically gave up and sold their EEZ to China. Commented Mar 18, 2019 at 15:10

"...But perhaps the ultimate security measure a ship owner can adopt is the use of armed security personnel, either provided by their government as Vessel Protection Details (VPDs) or through employing Privately Contracted Armed Security Personnel (PCASP), where Flag state rules allow. The latter are often made up of former members of various armed forces, who embark on merchant ships and guard them during transits through high risk waters. To date, not a single ship with armed security personnel aboard has been successfully hijacked. These teams have served as a game-changer in the effort to combat piracy.

For our part, the U.S. government has mandated that U.S.-flagged merchant vessels transiting the high risk area conduct a risk assessment with specific consideration given to supplementing onboard security with armed personnel.

When PCASP emerged on the scene a few years back, there were reservations. Many feared that armed security personnel would escalate the level of violence during pirate encounters, further endangering mariners. The opposite appears to have happened. From the evidence that we have seen, in most engagements, the attack ends as soon as pirates realize an armed security team is on board. Pirates often break off their boarding attempt and turn their skiffs around to wait for another less protected ship. These teams therefore have served as an effective deterrent.

However, PCASP teams come in varying sizes and, to be frank, in varying degrees of quality. Their emergence as a security option has brought with it complications. Varying national legal regimes complicate the movement of these teams and their weapons from ship-to-ship or ship-to-shore. Some flag states do not have clear legal guidelines for addressing armed security personnel and are struggling to formulate positions vis-à-vis armed security personnel at sea.

Untangling legal and policy issues related to armed security will take time. But the U.S. government is hoping to make progress. Last month, the U.S. Department of State hosted a working level meeting of policy specialists from 23 nations and international organizations. The intent of the meeting was to give participants an opportunity to share information about their national or organizational law and policy on PCASP, thereby allowing all involved to gain a more complete picture of the overlaps and gaps in legal regimes and policies from country to country. This is a crucial step in figuring out a way forward that addresses the thorniest differences.

As a legal matter, authority over the use of privately contracted armed-security personnel beyond territorial sea limits (12 nautical miles from land) falls to the flag State. Once a vessel with armed personnel embarked enters territorial seas it may carry such personnel provided it is engaged in innocent passage or transit passage. If a vessel with an armed team embarked intends to enter a port, the port State may exercise authority for regulating the personnel or their arms."


  • One fix for this is the "floating armory which is a boat or ship which the security contractors will sail just outside of international waters of countries that ban fire arms and wait for their contracting ship. They then board the ship and continue the voyage over the leg of international waters. For the Somali Piracy area, many of these floating armories make port in the Seychelles.
    – hszmv
    Commented Jul 16, 2019 at 15:16

The nearest response legally speaking of legitimate commercial enterprises acting in an armed manner (ie: guns on ships) would be closest resembling the Commerce Raiders of the latest world wars. The trading companies prior to the 18th Century were armed because of the laws relating to imperial networks, such as the British East India Trading Company having a royal charter, and therefore the authority to use military and naval force in Imperial Territories under its jurisdiction, with the added bonus of being able to fend of pirates and privateers. That was 200 years ago. Things are vastly different now. The most recent armed vessels remotely resembling armed merchant vessels or privateers were the commerce raiders employed most recently in WWII. These vessels, however, were commissioned by the nation of origin as naval vessels, and subject to the codes such forces abide by. As such, lack of legal precedence is only due to a lack of court cases relating to such actions in the modern age. The cases relating to piracy have regarded individuals, not whole ships or companies and their fitting out (what they carry onboard), at least since the Numenburg Trials post WWII.

Furthermore, weapons such as large cannon and torpedoes are virtually useless against vessels such as the skiffs, small fishing vessels and fast motor vessels most commonly used by pirates these days. The torpedo runs too deep to detonate under such a small hull, and a cannon would have a hard time aiming, even with modern electronic and mechanical stabilizers. The best weapons are small arms (such as the Browning 9mm pistol, AK-47, etc.) up to heavy machine guns (such as a Browning 12.5mm/.50 cal machine gun), as these are much more manouverable and fire more effectively at closer distances (you would only ever engage pirates at only a few hundred yards distance, as that is when their intention would become definitively known).

  • Welcome to SE. This response has a lot of good information but does not answer the question. The question is "What would be legal?" You talk at first about equivalency, but do not elaborate on what would be legal. Furthermore, it is strange that there is neither mention of UNCLOS or any LOS, formal or traditional whatsoever, in a question on piracy. Commented Feb 3, 2016 at 21:16

It's my understanding that when in international waters you are under the laws of your home country.

If you are American you could carry firearms on the boat, you would have to look up the laws on declaring them before entering any country's waters though. If you are a good rifleman you could probably kill them from several hundred yards out before then get close enough to use their crappy 40 year old AKs that probably haven't been properly cleaned in decades or RPGs. Do you think they can nail you at even 100 yards with one of those?

Just shoot them in the chest or head before they get close enough to get you.

I'd consult a lawyer before sailing around the world to make sure you are familiar with the laws.

Personally I think it should be legal to blood eagle them, crucify them on a mast, and cut off their heads but I wouldn't do that.

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    It's my understanding that when in international waters you are under the laws of your home country. That doesn't exactly fill me with confidence. care to validate that statement for us? Commented Apr 18, 2016 at 17:21

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