In the case of Fane Lozman v. The City of Riviera Beach, Florida (2012), the U.S. Supreme Court ruled in favor of Lozman, a houseboat owner who contested that his floating home was not a vessel and therefore should not be subject to maritime laws. The city had seized his houseboat over disputes about docking fees and used federal maritime law to justify their actions. However, the court decided by 7-2 majority that not all structures or entities that float on water can be classified as vessels under this law. They argued for a more practical interpretation where only those structures with transportation function or purpose could qualify as vessels; since Lozman's houseboat lacked these features it wasn't considered a vessel under maritime law.

In the dissenting opinion for Fane Lozman v. The City of Riviera Beach, Florida, Justice Thomas argued that Lozman's floating home should be classified as a vessel because it was capable of transportation on water. He disagreed with the majority’s interpretation of “capable” and “transportation,” arguing that they were ignoring the plain language of 1 U.S.C §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." According to him, this definition does not require an intent for use in transportation nor does it exclude structures like Lozman's houseboat just because they have some attributes common to land-based homes. Therefore he believed that since Lozman’s structure could and did move over water at various times during its life (even if infrequently), it met all requirements to be considered a vessel under federal maritime law.