Definition
A term with two distinct applications in law:
1. As applied to waterways: A stream, river, or body of water that is not capable of navigation — impassable by ships or vessels. This usage is primarily relevant to property law and the law of water rights, where navigability determines public access rights, federal jurisdiction, and the character of riparian ownership.
2. As applied to vessels (marine insurance): A vessel so damaged by perils of the sea that it is no longer capable of making a voyage. A vessel may be absolutely innavigable — beyond any reasonable repair — or relatively innavigable, meaning repairs would cost nearly as much as building a new vessel. This distinction bears directly on insurance loss determinations and constructive total loss analysis.
Common Language
Modern common usage (Wiktionary): Incapable of being navigated; impassable by ships.
Historical common usage (Webster's 1913): Incapable of being navigated; impassable by ships or vessels.
The common meaning captures the waterway sense cleanly. What ordinary usage misses entirely is the vessel-side meaning in marine insurance law — a technical application in which the term describes not a fixed geographic feature but a ship rendered unfit for further voyaging by maritime misadventure. Researchers must determine from context which meaning applies.
Recognized Forms
/SUBTYPES
Absolutely innavigable: A vessel so damaged as to be beyond repair under any practical circumstances; total incapacity for further navigation.
Relatively innavigable: A vessel technically repairable but at a cost approaching or equaling the expense of new construction. This is the more frequently litigated category, as it touches directly on constructive total loss determinations in marine insurance.
Why It Matters in Research
The dual application of this term creates a research trap that is easy to miss. Sources discussing innavigable waterways belong to an entirely different doctrinal conversation than sources discussing innavigable vessels. A researcher working on navigability doctrine under federal admiralty or property law may pull cases or treatise references that are actually addressing the marine insurance question, and vice versa.
The waterway sense of innavigable connects to the broader navigability framework that determines federal admiralty jurisdiction, public trust doctrine, and riparian rights. In that context, innavigable is essentially the negative form of navigable — a term with its own complex doctrinal history and shifting legal tests across federal and state courts. Researchers should not assume that a historical court's finding that a stream is "innavigable" tracks the modern federal navigability standard; the tests have evolved and differ depending on purpose (admiralty, commerce, property).
The vessel sense belongs to marine insurance law and is tied to the constructive total loss analysis. The relative/absolute distinction found in the historical dictionaries — drawn from European insurance law sources, particularly Emerigon and Targa — reflects the civil law roots of much early Anglo-American marine insurance doctrine. Researchers using historical sources here should be aware that the European treatise tradition heavily influenced American formulations through the early nineteenth century, and that Kent's Commentaries (the reference cited across multiple dictionary sources) was a primary transmission point.
For corpus researchers: the term appears infrequently in modern American legal writing. When it appears in nineteenth-century sources, confirm which sense applies before following the citation trail.
Historical Dictionary Support
The five source dictionaries show substantial agreement on the vessel/insurance definition, all tracking the absolute/relative innavigability distinction and citing the same foundational authorities — Emerigon's Traité des Assurances, Targa, and Kent's Commentaries (3rd volume, page 323, note). This convergence suggests that by the mid-nineteenth century, the doctrinal content of the term in insurance law was settled and sourced primarily from the European maritime tradition.
Rapalje & Lawrence and Burrill align most closely in language, both emphasizing "irremediable misfortune" as the trigger for absolute innavigability and the cost-of-repair test for relative innavigability. Bouvier adds the useful qualifier that this is "a term applied in foreign insurance law," acknowledging its civil law origins — a candor the Black's editions do not replicate.
Black's (both editions) is the only source to give meaningful space to the waterway definition alongside the insurance definition, reflecting the increasing doctrinal importance of navigability in American property and admiralty law by the time those editions were published. The earlier civilian-focused dictionaries treat the waterway sense as either obvious or secondary.
What the historical dictionaries collectively miss: they do not address how the innavigability of a vessel interacts with abandonment procedures, notice requirements to underwriters, or the procedural posture of constructive total loss claims. Those questions require moving beyond the dictionary sources to treatises and case reporters.
Jurisdictional Note
The waterway sense of innavigable is subject to significant jurisdictional variation. Federal navigability tests for admiralty jurisdiction, commerce power, and land grant purposes apply different standards, and state courts apply their own tests for property and public trust purposes. A finding of innavigability in one context does not carry across to others.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Navigability; Marine Insurance — Constructive Total Loss; Admiralty Jurisdiction