if not impossible, to determine the use of a human “contrivance” without some consideration of human purposes. At the same time, we have sought to avoid subjective elements, such as owner’s intent, by permitting consideration only of objective evidence of a waterborne transportation purpose. That is why we have referred to the views of a reasonable observer. Supra, at 1. And it is why we have looked to the physical attributes and behavior of the structure, as objective manifestations of any relevant purpose, and not to the subjective intent of the owner. Supra, at 5–6. We note that various admiralty treatises refer to the use of purpose-based tests without any suggestion that administration of those tests has introduced too much subjectivity into the vessel-determination process. 1 Benedict on Admiralty §164; 1 Admiralty and Maritime Law §3–6.
Second, the City, with support of amici, argues against the use of criteria that are too abstract, complex, or openended. Brief for Respondent 28–29. A court’s jurisdiction, e.g., admiralty jurisdiction, may turn on application of the term “vessel.” And jurisdictional tests, often applied at the outset of a case, should be “as simple as possible.” Hertz Corp. v. Friend, 559 U. S. ___, ___ (2010) (slip op., at 1).
We agree with the last-mentioned sentiment. And we also understand that our approach is neither perfectly precise nor always determinative. Satisfaction of a design-based or purpose-related criterion, for example, is not always sufficient for application of the statutory word “vessel.” A craft whose physical characteristics and activities objectively evidence a waterborne transportation purpose or function may still be rendered a nonvessel by later physical alterations. For example, an owner might take a structure that is otherwise a vessel (even the Queen Mary) and connect it permanently to the land for use, say, as a hotel. See Stewart, supra, at 493–494. Further,
