Definition
ANCHOR carries two distinct legal meanings, neither of which connects to the other except by historical coincidence of the same word appearing in different legal contexts.
1. Unit of liquid measure. In older commercial and mercantile law, an anchor is a unit of liquid capacity equal to ten gallons. This meaning appears primarily in contracts, customs documents, and cargo manifests from the era of bulk liquid trade, where quantities of wine, spirits, and oils were expressed in traditional merchant measures.
2. Nautical fixture and vessel appurtenance. In admiralty and maritime law, an anchor is the iron instrument attached to a vessel by cable or chain, cast overboard to grip the seabed and hold the vessel at a fixed position. In this context, anchor is legally significant not merely as a physical object but as part of the vessel's appurtenances — equipment considered legally attached to and part of the ship for purposes of sale, mortgage, lien, seizure, and insurance.
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Common Language
Modern common usage (Wiktionary): A tool used to moor a vessel to the bottom of a sea or river to resist movement; also used figuratively for anything that holds or stabilizes.
Historical common usage (Webster's 1913): An iron instrument attached to a ship by cable, cast overboard to hold the ship in a particular station by gripping the earth; also any contrivance serving an analogous stabilizing function.
The common meaning and the admiralty legal meaning largely align on the physical object. The legal gap arises in two directions: first, the commercial-law meaning as a unit of measurement has no counterpart in ordinary usage and will catch researchers by surprise in contract and customs documents; second, the admiralty treatment of the anchor as an appurtenance of the vessel — with legal consequences for ownership, encumbrance, and seizure — goes well beyond the physical object that common usage describes.
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Common Confusion
Two related distinctions require care. First, a vessel fastened to a pier is not "lying at anchor" in the legal sense — the vessel's status under maritime law (whether at anchor, moored, or beached) carries specific consequences for liability under collision rules, salvage law, and insurance policy terms. Second, a vessel purposely beached, even if an anchor is deployed as a precautionary measure, is not "at anchor" for legal purposes. These distinctions, noted in Anderson's, matter when reading historical admiralty cases or policy language that conditions coverage or liability on the vessel's status.
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Recognized Forms
/SUBTYPES
As a unit of measure, the anchor appears alongside related historical liquid measures including the firkin, kilderkin, barrel, and hogshead. The precise gallon-equivalents of these measures varied by commodity (wine, beer, spirits) and by jurisdiction, so the ten-gallon figure cited in the legal dictionaries should be verified against the specific trade context of the document under examination.
As an admiralty term, the anchor's legal significance flows from its classification as part of the vessel's furniture or appurtenances — a category that also includes masts, sails, rigging, and ship's tackle.
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Why It Matters in Research
Researchers encountering ANCHOR in historical legal documents face a threshold question: which meaning is operative? In admiralty pleadings, maritime insurance policies, ship mortgage instruments, and collision cases, anchor functions in its nautical sense and frequently carries appurtenance analysis with it. In commercial contracts, customs entries, excise records, and cargo disputes from the eighteenth and nineteenth centuries, anchor may simply be a unit of measure requiring conversion before any quantity dispute can be understood.
The admiralty meaning has corpus connections running to APPURTENANCE, FURNITURE OF A SHIP, and the body of law governing what passes with a vessel upon sale or mortgage. A ship's anchor is not mere movable property — its status as appurtenance means it travels with the vessel legally even when not physically attached at the moment of a transaction or seizure.
The measurement meaning is largely obsolete in modern commercial practice but surfaces frequently in historical cargo manifests, bond documents, and excise records. Researchers working with pre-twentieth-century trade documents should not assume gallons without verifying whether a named measure like anchor, firkin, or tierce is being used instead.
The "lying at anchor" distinction identified in Anderson's connects to a discrete body of admiralty liability rules. Whether a vessel was at anchor, moored, or underway at the time of an incident governed which rules applied to collision liability, salvage rights, and insurer obligations under voyage versus time policies.
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Historical Dictionary Support
The historical dictionaries are in agreement on both core meanings but contribute unevenly. Black's (both editions) and Bouvier's define anchor primarily as the ten-gallon liquid measure, with Bouvier's adding the maritime-instrument definition and citing admiralty authorities. Anderson's contributes the most practically useful guidance for legal research: the clarification that a vessel fastened to a pier is not "lying at anchor," and that a purposely beached vessel with an anchor deployed for caution does not qualify either. Anderson's cross-references to APPURTENANCE and FURNITURE OF A SHIP point researchers toward the doctrinal context where the anchor's legal status as vessel equipment becomes consequential.
What the historical dictionaries collectively miss is any treatment of the anchor as a unit of measure in relation to other contemporary measures or commodity-specific variations. The flat "ten gallons" definition, consistent across sources, obscures the variation that existed in practice. Researchers relying solely on these sources for quantity conversion in historical trade disputes should consult contemporary merchant manuals or commodity-specific statutory tables.
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Jurisdictional Note
The admiralty meaning is governed by federal admiralty jurisdiction in the United States and falls under the general maritime law, making it largely uniform nationally. The measurement meaning is a historical artifact of English and early American commercial practice; its precise equivalents varied by English statute and commodity type, and American practice sometimes diverged from English standards.
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