Power ships today represent the cutting edge of innovation, making the source and production of energy movable. Increasing and variable demand for energy has caused local authorities to face new demands for production. Immediate energy demands must be met but investment should not lead to long-term entrenchment of infrastructure likely to be outdated quickly. A solution is to use short-term structures while promoting investment in more sustainable energy resources. In this context, floating power installations may be a useful option.
A power ship project envisages the development of a special purpose marine vessel on which a power plant is permanently installed to serve as a power generation resource.1 The concept at present revolves around the conversion of an existing ship. Such ships can provide immediate solutions to the energy needs of states where the energy needs exceed the capacity of the available infrastructure for energy generation and where imports of energy through neighbouring countries is not possible. Power ships could further be deployed in areas stricken by natural disaster where the energy installations are damaged or destroyed. Such a power ship will moor at a location for a period, which will be in the order of years or even decades. A power ship can thus partly serve a state’s energy demands until national infrastructure is developed.
The fact that power ships are technologically designed to be mobile, but commercially aim to stay in the same location for a number of years raises questions as to the application of maritime law, designed for movable objects. This article explores the characteristics of power ships in relation to the various definitions of “ship” in maritime law.
What is a ship?
Is a power ship a floating power station or a power-generating ship? There is no definition of “ship” that fits all situations. By way of example, neither the 1952 Arrest Convention nor the 1999 Arrest Convention provides an express definition of “ship”, but relies on domestic law to provide such definition. Either Convention may become applicable to the arrest of a power ship, depending on where she is located at the time of arrest: whether stationary in operation or in a temporary port of call. Past and present locations include Lebanon, which has signed (but not yet ratified) the 1952 Convention and Pakistan, which has signed (but not yet ratified) the 1999 Convention.
Section 313(1) of the Merchant Shipping Act 1995 defines a ship as including “every description of vessel used in navigation”, but the use of the word “includes” means that the definition is not exhaustive. A definition of ship has been said to encompass two elements:2 first, it has to be distinguishable with physical characteristics so that it can be described as a vessel; secondly, as to its purpose, it must be used in navigation.3
The issue was memorably stated by Scrutton LJ in 1926: “One might possibly take the position of the gentleman who dealt with the elephant by saying he could not define an elephant, but he knew what it was when he saw one”.4 In other words, a person cannot define a vessel or ship but can recognise it when he encounters it.5 The importance of the physical characteristics of a ship is that without this characteristic, it cannot be measured under the tonnage regulations,6 a surveyor cannot issue a tonnage certificate and the ship will not be registered.
By way of example, in Wells v Owners of the Gas Float Whitton (No 2)  AC 337, the House of Lords considered whether a gas float should be treated as a ship. A gas float – shaped like a boat but neither intended nor fitted to be navigated – was moored in tidal waters to give light to vessels. It was held that not being a ship or part of a ship or of her apparel or cargo, the structure was not the subject of a claim for salvage within the Admiralty jurisdiction.
Thus, in order to satisfy the first element of the definition, physical characteristics take an important role. It is submitted that a person encountering a power ship will generally perceive and recognise it as a ship. A power ship would thereby satisfy Scrutton LJ’s “elephant test”.
The second characteristic of being a “navigable object” was discussed in Perks v Clark  2 Lloyd’s Rep 431. The definition followed by Carnwath J provides that navigation “does not necessarily connote anything more than ‘movement across water’” (at para 47). There are two different aspects related to the notion of a navigable object. Numerous cases have attempted to explain whether an object is sea-going so that it may be considered as a ship. They consider whether an object is sufficiently mobile to be a vessel as opposed to some other structure.
Thus Ex parte Ferguson (1871) LR 6 QB 280 concerned a coble, a form of fishing boat, which had been run down by a steamer. The question for the court was whether the craft was navigable and also sea-going, although she could be propelled by oars. The court referred to the “business” of the craft, that is to say, its nature and the intention to use it “really and substantially to go to sea”. Neither the size nor the tonnage was a factor to be taken into account for a structure to be qualified as a ship. A power ship can therefore arguably satisfy the criteria of being a navigable object. Since part of the purpose of a power ship is to go to sea, a power ship can be considered a ship.
In R v Goodwin  1 Lloyd’s Rep 432, the Court of Appeal considered that to be a ship, a vessel has to move from one place to another, and considered that a jet ski was not a sea-going ship. Accordingly, a power ship can be considered a sea-going vessel in the sense of being a navigable object, because it does navigate from an originating place A to the operating venue at terminus B.
Moored power ships
A power ship is a ship, dedicated to the purpose of the generation of energy, with an on-board power plant as a resource. In performing this task, the power ship is moored at the port of the state for five or six years, during which period the only purpose and object of the ship is to supply energy to the port state.
Power ships are not unique in having mixed characteristics. The floating liquefied natural gas platform Prelude FLNG of Shell7 is intended to be towed to location and stay moored there. Applying the test in Perks v Clark, such a unit would not be considered a ship because it cannot independently move across the water. In Merchants Marine Insurance Co v North of England Protection and Indemnity Association (1926) 26 Ll L Rep 201;  32 Com Cas 165, the Court of Appeal held that although a floating crane platform had the shape of a vessel and was capable of being moored in different places, it could not be considered a ship. The reason was that it was not used as a navigable object. The court held that the pontoon, although movable for the purpose – it moved approximately five to six times (limited movement) – could not be regarded as a ship or vessel.
Similarly, in The Upcerne  P 160 the question was whether a gas-powered lightning buoy was a ship for the purpose of admiralty jurisdiction. It was held that the primary purpose for which the buoy was designated was not to navigate, although it was fully capable of movement and it moved from time to time in order to operate elsewhere. The buoy did not move from its position while it was performing its work, but it was fixed to the bottom of the sea. Comparing this with power ships, the latter do not, in order to perform their work, move from their position. However, a power ship does have the additional characteristic of being used for navigation. The case is indeed not very helpful in seeking to draw a distinction between vessels with limited use in navigation and those unable to move from their position. Another example is given in the decision R v Carrick District Council, ex parte Prankerd (The Winnie Rigg)  2 Lloyd’s Rep 675. The decision concerned a yacht moored in Truro harbour for 15 years. The issue was whether Winnie Rigg was a ship “used in navigation”. The judge noted (at page 679 col 1) that the phrase “used in navigation” connoted that the ship was actually or potentially capable of being used for navigation and that she remained so although rendered incapable of navigation, so long as there was a reasonable expectation that she would regain her capacity to navigate. The meaning of “used in navigation” was also considered by Sheen J in Steedman v Scofield  2 Lloyd’s Rep 163: “To my mind the phrase ‘used in navigation’ conveys the concept of transporting persons or property by water to an intended destination … Navigation is planned or ordered movement from one place to another”.
To sum up, it may therefore be argued that a power ship does satisfy the element of being a navigable object inasmuch as it does not lack movement. However, considering the periods that the power ship is moored in the port, the result may be different. For example, if a ship “A” is moored in the port for approximately two years, then perhaps the element of movement subsists. Indeed, there appears to be a sliding scale permitting argument one way or another in respect of the ship’s mobility, leaving open the debate as to their navigability. On the other hand, if the same ship “A” is moored in the port for more than 10 years, then it would seem obvious that, due to the lack of movement, the ship is not capable of being considered a navigable object. Further factors the law might be able to take into account in fine-tuning the test for power ships might be whether the ship is disabled somehow during the stationary period, namely whether important engine parts are removed and then refitted before departure. It might also be pertinent to consider whether the vessel is capable of independent movement or must be towed or otherwise aided.
A different test has appeared in United States case law. If the “vessel issue” arises in connection with floating structures or platforms that have a specialised function in a port, harbour or shipyard while they are in use, then such structures are not considered to be in navigation as they are almost permanently fixed to the shore: although in Offshore Co v Robison 266 F.2d 769 (5th Cir, 1959) it was held that an offshore drilling platform was a vessel. According to the “purpose test” in determining whether a structure amounts to a vessel, the following criteria are to be taken into account: (1) In Lozman v City of Riviera Beach 649 F.3d 1259 (11th Cir, 2011), the court considered the vessel’s capacity of transportation across the water under the Rules of Construction Act USC section 3, which defines a “vessel” as including “every description of watercraft or other artificial contrivance used, or capable of being used, as a means of transportation on water”; (2) In Stewart v Dutra Construction Co 543 US 481 (2005), page 495, the court considered whether the object in question was designed to be permanently fixed in position. This must mean, by negative implication, that a permanently moored structure never falls within the definition of ship. Presumably, this encompasses those kinds of ships “otherwise rendered practically incapable of transportation or movement”.
Based on this purpose test, structures such as those under discussion would not be considered ships or vessels. However, it is also important to determine at what point in time the particular claim in question arose. In relation to claims arising when the structures are stationary and not in navigation, they may be denied “vessel” status (Brunet v Boh Brothers Construction Co 715 F.2d 196 (5th Cir, 1983)). For instance, the design of the structure of a fixed platform may show that it is not intended to be moved and it will accordingly not qualify as a vessel (Blanchard v Engine & Gas Compressor Services Inc 575 F.2d 1140 (5th Cir, 1978) (gas compressor station fixed to ocean floor)).
Considering the above, the issues to consider in defining a
power ship as a ship under the law are the following. Is she capable of free and ordered movement? Is she navigable as a sea-going object? Is she capable of use in navigation? In addition, under the “purpose test” as applied in US law, it is pertinent to determine at what point in time the claim arose to determine whether she is a vessel with rights to tonnage limitation of liability, navigational duties and so forth.
What seems apparent is that a power ship should be considered a ship at the beginning of the voyage and during the voyage, because at that stage it certainly meets all the requirements.
Sinem Ogis, LLM student, University of Southampton
(accessed December 2014).
2 Mandaraka-Sheppard, Modern Admiralty Law, 1st Edition, 2001, page 17.
3 Summerskill, Oil Rigs: Law and Insurance (Some Aspects of the Law and
Insurance relating to Offshore Mobile Drilling Units, Stevens & Sons, 1979,
4 Merchants Marine Insurance Co v North of England Protection and Indemnity
Association (1926) 26 Ll L Rep 201;  32 Com Cas 165, CA.
5 See also Shaw, “ What is a ship in maritime law?” (2008) JIML 11(4), pages
247 to 249.
6 Merchant Shipping (Tonnage) Regulations 1997 (SI 1997/1510) as amended.
7 www.shell.com/global/aboutshell/major-projects-2/prelude-flng.html (accessed