The embarkation of private armed guards on commercial ships in Somalia has provided a unique opportunity to test the bounds of international law. The phenomenon was new. Until that point shipowners had been reticent to carry weapons or engage the services of those carrying weapons. The legal and practical risks of such carriage or engagement outweighed the potential benefits they offered to defend vessels. Somalia, however, was genuinely peculiar. While shipowners had contended with piracy before, for example in the Straits of Malacca, Somalia represented a potent combination of a failed State with a large, difficult-to-patrol and strategically vulnerable coastline. Shipowners began to engage the services of private maritime security companies (PMSCs) and their privately contracted armed security personnel (PCASP) to safeguard the passage of vessels through the Gulf of Aden, adjacent to Somalia, which is also the second busiest shipping lane in the world. By 2011 it was estimated that up to 50% of vessels sailing through the Gulf of Aden were using the services of armed guards. This new phenomenon gave rise to particular concerns under public international law regarding the law of the sea (and the safety of life at sea in particular) and international human rights protection. These concerns reverberated into private domestic legal concerns as shipowners, marine underwriters and indemnifiers became alarmed at the potential vulnerability of their commercial arrangements on the grounds of illeg- ality and public policy, in addition to their potential liability stemming from the use of force.

While international law did have some norms relevant to the embarkation of armed guards, targeted regulation was lacking. Applicable rules had to be distilled from a variety of legal worlds: international and domestic, public and private. Member States of the International Maritime Organization (IMO) were slow to respond to this phenomenon. Many States were reticent to cooperate on regulatory initiatives out of fear that such initiatives would be seen to condone the use of guards. Despite this, shipowners and PMSCs did not stop embarking armed guards due to the lack of regulation. Rather, some PMSCs took advantage of the lack of regulation to cut corners and contract on terms that were arguably a prima facie violation of the law of the sea (in particular the role of the shipmaster). The use of armed guards off the Somali coast has tested the ability of the law of the sea framework enshrined in the United Nations Convention on the Law of the Sea (UNCLOS) to respond to the use of force at sea. A lack of targeted governmental regulation motivated the shipping and insurance industries to develop regulatory initiatives including: the ISO 28007-1:2015 Guidelines for PMSCs Providing PCASP on Board Ships (ISO 28007:2015), the GUARDCON Contract for the Employment of Security Guards on Vessels and the 100 Series Rules as to the Use of Force (100 Series RUF). These instruments incorporate international norms concerning the law of the sea and human rights law into commercial shipping and insurance arrangements.

This dissertation examines both the public international law framework and the role of private ordering in this context. The following research questions are addressed:

1. Who is responsible for the acts of PCASP at sea and why?
2. How does private ordering contribute to the governance of PCASP at sea?

This dissertation argues that, despite public international law having the substantive norms necessary to address the embarkation of armed guards at sea, it is undermined by the prominent and problematic doctrine of flag State jurisdiction over vessels. The result has been gaps in the enforcement of international law giving rise to a practical impunity being enjoyed by armed guards in terms of their conduct. The industry initiatives have a unique role to play alongside public international law in helping to close these enforcement gaps. Despite this, the potential of these industry initiatives is weakened by the difficultly of measuring their effectiveness given the lack of transparency over how they are enforced in practice. Their potential is further undermined by a lack of dispute resolution options to effectively redress harm caused by armed guards. While industry contributions to regulation have great promise, they would be strengthened through stronger reporting requirements and the adoption of current proposals to allow arbitration of human rights violations committed at sea.