Nations and empires have been built through the work of seafaring soldiers of fortune. For centuries, maritime history has been a story of one ship’s crew – and whatever power backs it – outmanoeuvring another. As the legendary navigator Ahmad ibn Majid, who was born in the 15th century in present-day Ras Al Khaimah, once wrote of the trade secrets that allowed Arab maritime powers to outcompete European ones: “They cannot understand the way we navigate, but we can understand the way they do.” But fortune-seeking on the high seas can harm nations just as easily as it can help them prosper. The world’s oceans can be a haven for criminals, particularly smugglers – of drugs, weapons, people and more. Understanding the way they navigate and outmanoeuvring them is proving to be one of the most difficult jobs for law enforcement agencies around the globe. On Sunday, the US Navy announced that it had seized a cache of illegal arms smuggled aboard a dhow in the Arabian Sea. The haul included assault rifles, machine guns, anti-tank guided missiles and rocket-propelled grenade launchers. While the vessel’s point of origin and final destination are yet to be established, the ongoing conflict in Yemen continues to see a significant degree of maritime smuggling to supply weapons to the Houthi rebel group that overthrew the legitimate government of the country. Although the materiel aboard the dhow was intercepted, delivering justice to those who dispatched and paid for it will be made harder by the fact that the vessel bore no national flag. International law mandates that any ship travelling for commercial purposes be registered in a particular country, its “flag state”, and be subject to its maritime and taxation laws. This is precisely why smugglers so often choose to either fake their flags, or not fly them at all. Prosecuting activities that occur in international waters is already a murkier area of international law, and it is made much more difficult when those carrying out the activities present no return address. The policing of the waters surrounding the GCC region is providing a model for how the problem can be overcome. While Article 110 of the UN Convention on the Law of the Sea allows for navies to board so-called “stateless vessels”, exercising jurisdiction over such vessels, their cargo and their crew becomes more complicated. The first two are more straightforward, provided that the vessel is suspected of committing certain crimes, such as piracy, which could be policed under the principle of universal jurisdiction. The US and its allies have over the years expanded the boundaries of universal jurisdiction to encompass activities such as arms smuggling and sanctions busting. Exercising jurisdiction over crews, however, who are usually not stateless, but rather citizens of a country, is much thornier. The home nation of those caught carrying out shady activities in international waters are usually reluctant to protect them, and any effort to prosecute them elsewhere becomes crippled by legal ambiguities. In the case of the stateless dhow, the US Navy questioned the crew, fed them and gave them water before releasing them. It is not a perfect solution to what is becoming an increasingly serious problem. Regulating the high seas and preventing them from becoming staging grounds for wars happening ashore will continue to be a challenge in international law. But in the Arabian Sea, at least, the smuggler's life is getting harder.