Fact-checked by Grok 2 weeks ago

Fathom

A fathom is a unit of length in the imperial and U.S. customary systems, equal to six feet (1.8288 meters; precisely defined in 1959), primarily employed to measure water depth in nautical navigation.^[1]^[2]^[3] Originating from Old English fæþm, meaning the span of outstretched arms, the term dates to before the 12th century and reflects an anatomical basis for early measurements.^[1] By the 1600s, it was in use for measuring depths with sounding lines to gauge underwater depths, aiding safe passage for ships.^[1] Today, the National Oceanic and Atmospheric Administration (NOAA) incorporates fathoms on certain nautical charts alongside feet and meters to denote soundings—the vertical distance from chart datum to the seabed—essential for assessing under-keel clearance.^[2] Historically, fathoms extended beyond maritime use to measure mine depths in the United Kingdom until the early 20th century, though modern applications remain predominantly nautical.^[4] Conversions are straightforward: one fathom equals 1.8288 meters, and depths like "five fathoms" indicate 30 feet or approximately 9.144 meters.^[2] This unit persists in specialized contexts, such as hydrographic surveys and fishing charts, where features like fish havens are marked if their minimum depth is 11 fathoms or less.^[2]

Definition and Etymology

Definition

The fathom is a unit of length in the imperial and United States customary systems of measurement, standardized at exactly six feet or 1.8288 meters in international and US usage (variations such as the former British Admiralty fathom of 6.08 feet are detailed in later sections).^[5] The term derives from the Old English fæþm, referring to the span of outstretched arms, which originally informed its approximate length.^[6] Primarily employed as a nautical unit, the fathom measures water depth on nautical charts and during sounding operations, where depths are often marked in fathoms to indicate safe navigation clearances.^[7] For instance, one fathom equals six feet, facilitating quick assessments by mariners using lead lines or echo sounders calibrated in this unit.^[8]^[9] The fathom's metric equivalent was fixed by the 1959 international agreement defining the yard as exactly 0.9144 meters.^[5] This alignment supported consistent use in global hydrographic practices, though bodies like the International Hydrographic Organization have increasingly promoted metric alternatives for surveys.^[10]

Etymology

The term "fathom" derives from the Old English word fæþm, which denoted the "outstretched arms" or an "embrace," reflecting a unit of measurement based on the human body's span.^[6] This Old English form traces back to the Proto-Germanic root faþmaz, meaning "embrace" or "something embraced," emphasizing the encircling gesture of the arms.^[6] Cognates appear in related languages, such as Old Norse faðmr for "embrace" and Middle Dutch vadem for a similar measure, underscoring its Germanic linguistic heritage.^[11] Through its evolution into Middle English as fathme or fadme, the word retained its core association with arm extension while expanding metaphorically.^[6] By this period, it had developed a verb form, fathmen, meaning "to encircle with the arms" or "to probe by feeling," which later broadened to signify "to comprehend" or "to understand deeply," as in grasping an idea within one's intellectual "embrace."^[6] This shift highlights how the term's physical origins influenced abstract usage in modern English, where "fathom" persists both as a noun for measurement and a verb for penetration of meaning.^[11] Historically, the word's connection to human anatomy is evident in its representation of the distance from fingertip to fingertip with arms fully extended, a practical anthropometric standard that informed early linear measures.^[6] This bodily basis later standardized the fathom at approximately six feet in nautical contexts, linking etymology directly to its functional role in depth sounding.^[11]

Historical Development

Ancient Fathoms

In ancient civilizations such as Egypt, Greece, and Rome, the fathom and its equivalents were non-standardized units of length derived from the span of a person's outstretched arms, typically around 6 feet (1.8 meters), with variations such as the Greek orguia from 1.77 to 2.00 meters based on regional standards. These measures were practical for hands-on tasks like surveying land after Nile floods or estimating construction dimensions, as they required no tools beyond the human body. Archaeological evidence, including cubit rods and inscribed standards, confirms this variability, with lengths adjusted to fit the average physique of workers in each society.^[12] In ancient Egypt, the "meh" (royal cubit) formed the basis for longer spans, measuring approximately 0.525 meters from elbow to fingertip, but longer measures derived from multiples of the cubit were employed in pyramid construction and land measurement, as seen in the precise alignments of Giza structures. Herodotus described the Great Pyramid's height as 100 fathoms (600 feet or 183 meters), equating the fathom to six feet or four cubits, though the actual height is approximately 146 meters, highlighting how such measures facilitated large-scale engineering without uniform tools. Papyri like the Rhind Mathematical Papyrus further illustrate their use in calculating areas for taxation and building.^[13]^[14] The Greek "orguia" directly mirrored the fathom concept as the full arm span, valued at six podes (feet) and ranging from 1.77 meters in Attic standards to 2.00 meters in Aeginetan ones, applied in Homeric epics for describing sea depths and in architectural works like temple foundations. Roman adaptations, influenced by Greek systems, incorporated similar arm-based estimates in military engineering and aqueduct surveys, though often calibrated against the pes (foot) for consistency, with spans approximating 1.6 meters in Vitruvian descriptions of human proportions.^[15] These variable ancient fathoms laid the groundwork for more standardized forms emerging in medieval Europe.^[12]

Medieval and Early Modern Fathoms

During the medieval period, the fathom served as a practical body-based unit for measuring lengths in nautical contexts across England and Scandinavia, typically standardized at 6 feet though with some regional variations. In England, it derived from the Anglo-Saxon term for "embrace," representing the span of outstretched arms, and was employed in shipbuilding to gauge timber dimensions and in fishing to assess net or line depths.^[16] By the 14th century, the fathom was standardized at 6 feet in England for greater consistency in trade and construction, though regional variations persisted among merchants and fishermen.^[16] In Scandinavia, the Old Norse equivalent, faðmr, similarly approximated 2 yards (about 6 feet) and was integral to Viking-era shipbuilding for hull framing and oar spacing, as well as fishing operations along coastal waters.^[17] This unit built upon ancient precedents of anthropometric measures, adapting them to the demands of maritime economies in northern Europe. In the 16th to 18th centuries, British naval practices refined the fathom amid expanding trade and warfare, emphasizing its role in rope-making and vessel outfitting to ensure uniformity in supply chains. Statutes regulating naval provisions, including the production of hempen ropes for rigging, incorporated the fathom as a key measure, with ropes often specified in multiples of fathoms to standardize lengths for anchoring and sails—typically 6 feet per fathom to align with the growing Royal Navy's needs.^[18] These refinements addressed inconsistencies in earlier applications, as an act of Parliament defined the fathom explicitly as the length of a man's outstretched arms, promoting reliability in shipyards like those in Chatham.^[18] By the 18th century, the unit's variability had narrowed in naval contexts, with fishing vessels and merchant ships adopting the 6-foot standard to facilitate international commerce, though some regional uses retained slight deviations for practical tasks like net deployment.^[16] The influence of transatlantic trade routes and exploration further highlighted the fathom's inconsistent applications during this era, particularly in logs from voyages like Christopher Columbus's in the late 15th century. Columbus's journal records depths in fathoms—such as 15 to 16 fathoms near island shores or 40 fathoms off Puerto de San Nicolas—reflecting Spanish braza equivalents (around 5.68 feet), which differed from English standards and led to ambiguities when integrated into broader European navigation records.^[19] These variations arose from regional differences, with explorers adapting local units for sounding lines and cable lengths, complicating standardization until later British naval reforms. Such discrepancies underscored the fathom's evolution from a flexible medieval tool to a more defined measure in early modern maritime endeavors.^[19]

Modern Variations

International Fathom

The international fathom is defined as exactly 1.8288 meters, equivalent to six international feet, establishing a precise metric-aligned standard for length measurement in nautical contexts. This definition stems from the 1959 international agreement on the yard, where one yard was set to 0.9144 meters exactly, making the foot 0.3048 meters and thus the fathom 1.8288 meters; this alignment was adopted by major nations including the United States, United Kingdom, Canada, Australia, New Zealand, South Africa, and India to resolve discrepancies between imperial variants and facilitate global interoperability.^[20] The adoption occurred in the mid-20th century as part of broader efforts to modernize measurement systems for hydrography, ensuring consistency in international maritime documentation. The International Hydrographic Organization (IHO), originally founded in 1921 as the International Hydrographic Bureau, played a role in standardizing the use of the fathom in international nautical charts during the 1920s through 1950s by coordinating hydrographic practices among member states and promoting uniform units for charting ocean depths. Through conferences and publications, the IHO encouraged the use of the fathom in depth soundings while integrating metric equivalents, reflecting its origins in British imperial measurements but evolving toward international precision. This standardization addressed variations in earlier definitions, supporting safer navigation by enabling comparable data across borders. In practice, the international fathom is applied in global nautical charts, where depths may be expressed in fathoms (abbreviated "fm" or "fms") alongside optional conversion tables to meters, particularly on medium- and large-scale charts. The IHO's regulations specify that such usage is at national discretion but must include clear notations like "DEPTHS IN FATHOMS" for transparency, with primary preference given to metric units to align with modern hydrographic standards. The conversion equation remains straightforward: $1 fathom = 6 feet = 1.8288 m, underscoring its utility in legacy and transitional charting systems worldwide.^[21]

British and American Fathoms

The British fathom is defined as exactly 6 feet, equivalent to 1.8288 meters, a standard codified within the imperial system through the Weights and Measures Act of 1856, which established precise definitions for linear measures including the foot from which the fathom derives. Historically, the British Admiralty defined the nautical fathom as 6.08 feet (1/1000 of the imperial nautical mile of 6,080 feet), but modern usage aligns with the international standard of exactly 6 feet.^[22]^[3] This unit has remained consistent in British usage for nautical and surveying purposes, reflecting the arm-span origin but fixed to the imperial yard of 0.9144 meters exactly.^[23] In contrast, the American fathom historically aligned with 6 feet under customary systems but featured slight variations in official surveys, particularly by the U.S. Coast and Geodetic Survey, where it was effectively 6.0802 feet based on the nautical mile definition of 6,080.20 feet until alignment with international standards.^[24] This discrepancy arose from tying the fathom to the U.S. nautical mile, which differed marginally from the British imperial version until metric harmonization efforts. For comparison, the international fathom standardizes at 1.8288 meters, matching the modern British definition.^[25] Following the 1959 adoption of the international foot (0.3048 meters exactly) by the U.S. for general measurements, the American fathom standardized to precisely 6 international feet, aligning fully with the British and global nautical practice. Despite this shift, the fathom persists in specialized U.S. applications such as commercial fishing gear specifications and recreational diving depth assessments, where it continues to denote 6 feet informally.^[26]

Other Definitions

In mining and engineering, the fathom serves as a unit for measuring shaft and seam depths, defined as 6 feet (1.8288 meters). This application appears in historical records of 19th-century U.S. mining operations, where it provided a practical scale for vertical excavations. For instance, at the Wheatley Mine in Pennsylvania's Phoenixville area, an engine shaft was sunk to a depth of fifteen fathoms during early zinc extraction efforts in the 1860s.^[27] Similarly, mining glossaries confirm the fathom's role in denoting shaft depths or seam thicknesses, often in coal and metal extraction contexts, retaining the traditional 6-foot basis akin to its nautical origins.^[28] In modern niche uses, such as recreational angling, the fathom measures water depths for line deployment and regulatory boundaries, applied in both coastal and inland settings beyond primary nautical surveying. This distinguishes it by focusing on angler-specific constraints, like depth limits to conserve fish stocks. In California's recreational groundfish fishery, for example, take of certain species is prohibited inside the 20-fathom (120-foot) boundary line during specific seasons, guiding hook-and-line fishing practices.^[29] Such regulations, enforced by state wildlife agencies, ensure sustainable angling while using the fathom for precise contour delineation on charts.^[30]

Derived Units

Derived units from the fathom include multiples and subdivisions used primarily in nautical contexts for measuring distances and depths. The cable's length, a traditional unit for anchor chains and short nautical distances, was originally defined as 100 fathoms, equivalent to 600 feet or approximately 182.88 meters.^[31] In historical usage, this measure reflected the practical length of a ship's anchor cable, though modern standards sometimes adjust it to one-tenth of a nautical mile (about 101 fathoms or 608 feet).^[31] Another derived unit is the nautical league, defined as 3 nautical miles and historically equivalent to approximately 3,041 fathoms.^[32] This larger measure, rooted in medieval European navigation, provided a scale for longer sea voyages, with the fathom-based reckoning tying it directly to depth-sounding practices.^[32] In river navigation, particularly on the Mississippi, the term "mark twain" denotes a depth of exactly 2 fathoms, or 12 feet, called out during lead-line soundings to indicate safe water for steamboats. This subdivision emphasized the fathom's role as a base for precise depth calls, where "mark" referred to the knotted indicators on the sounding line at fathom intervals.

Nautical Equivalents

The nautical mile, a fundamental unit in maritime navigation, is approximately equivalent to 1,000 fathoms, stemming from the British Admiralty's historical definition of the fathom as 6.08 feet to align precisely with one-thousandth of the imperial nautical mile of 6,080 feet.^[33] The modern international nautical mile, standardized at 1,852 meters or 6,076.11549 feet, equates to roughly 1,012.69 fathoms when using the 6-foot fathom.^[34] This close approximation facilitated practical calculations in navigation and surveying, where depths and distances were often expressed in fathoms relative to the mile. In anchor chain and cabling, a shot or shackle represents 15 fathoms (90 feet), a length standardized for ease of handling and storage in naval operations.^[35] The British Royal Navy adopted this 15-fathom measure in 1949, shifting from an earlier 12.5-fathom standard, while the U.S. Navy and merchant services had already employed it, ensuring interoperability in chain assembly where shots connect via detachable links.^[36] Historically, the fathom tied into sailing logs through speed measurements via the chip log, where knots on the line were spaced 8 fathoms (48 feet) apart to calibrate distance over a 28-second sand glass interval, directly influencing logbook entries of vessel progress.^[37] Additionally, the fathom's length of two yards connected it to the yard unit, derived from a pace-like arm span, allowing both to appear in nautical records for short distances, ropes, and lead-line soundings.^[38] Such as the cable, a traditional unit often reckoned at 100 to 120 fathoms, further integrated the fathom into broader nautical scaling.^[31]

Applications

Water Depth Measurement

The fathom has long served as the primary unit for measuring water depths in nautical navigation, particularly through the traditional method of lead-line sounding. A lead line consists of a weighted plummet attached to a rope marked at intervals of one fathom, allowing a leadsman stationed in the ship's chains to heave the line forward, let it sink to the seabed, and call out the depth once it reaches bottom, often reporting it simply as "X fathoms" to guide safe passage and anchoring.^[39]^[40] This practice, dating back to at least the 5th century BCE, not only determined depth but also sampled the seabed composition via a hollow in the lead filled with tallow or grease, enabling mariners to identify sand, mud, or rock for hazard assessment.^[39]^[41] Historical expeditions exemplified the fathom's role in systematic sounding for exploration and charting. During Captain James Cook's first voyage (1768–1771) aboard HMS Endeavour, soundings were routinely taken and recorded in fathoms to map unknown coasts; for instance, on October 12, 1769, off New Zealand's Cape Table, depths ranged from 20 to 30 fathoms while steering 2–3 miles offshore, and later that day between a rock and the land, readings of 17, 18, and 20 fathoms confirmed navigable channels.^[42] Similarly, on October 15, 1769, in Hawkes Bay, soundings decreased from 12 to 8 fathoms as the ship approached the south point, aiding precise positioning amid reefs and shoals.^[42] Cook's journals, such as entries from August 1768 in Plymouth Sound (9 to 6 fathoms) and December 1768 (50 to 40 fathoms with sandy bottoms), underscore how fathom-based soundings were integral to avoiding groundings and constructing accurate coastal surveys.^[42] In modern hydrographic surveys, the fathom persists on nautical charts despite the global shift toward metric units, providing continuity for mariners familiar with imperial measurements. The National Oceanic and Atmospheric Administration (NOAA) standards specify that depths, or soundings, on U.S. charts may be depicted in feet, fathoms (where one fathom equals six feet), or meters, with the unit clearly stated in the chart's title block and often using subscript notations like "5₂" to indicate 5 fathoms and 2 additional feet.^[7] For example, NOAA's Chart No. 1 outlines conventions where fathom curves connect points of equal depth, and hybrid units (fathoms plus feet) are common on coastal charts to balance precision and tradition, even as multibeam sonar has largely replaced manual lead lines for data collection. This dual-unit approach ensures compatibility with international shipping while supporting detailed bathymetry for safe navigation in depths up to hundreds of fathoms.^[7]

Rope and Line Length

In maritime settings, the fathom has long served as a practical unit for measuring the length of ropes, cables, and lines used in ship rigging and anchoring. Historically, ropes for rigging were manufactured and supplied in standardized lengths measured in fathoms to ensure consistency and ease of handling aboard vessels. For instance, basic ropes were typically produced in 150-fathom lengths, which were then combined into hawsers of 120 fathoms, and further into cable-laid cables of 100 to 115 fathoms, facilitating the construction of durable standing and running rigging essential for sail control and structural integrity.^[43]^[44] These measurements allowed riggers to coil and deploy lines efficiently, with the cable unit—derived as approximately 100 fathoms—representing a key multiple for longer assemblies like anchor cables.^[44] In historical naval practices, fathoms provided a precise increment for paying out anchor lines or chains during maneuvering, enabling captains to adjust scope based on conditions such as tide, wind, and vessel speed. For example, during anchoring to check headway or break a sheer, crews would release initial slack of 2 to 15 fathoms before applying the brake, or extend to 30 fathoms or more if the anchor dragged, ensuring the chain's catenary provided sufficient holding power without excessive strain on the windlass.^[45] This fathom-based system persisted into modern navies, where anchor chains are segmented into "shots" of 15 fathoms each, allowing systematic payout—often 5 to 7 times the water depth—for secure mooring.^[45]^[44] In contemporary sailing and sport fishing, fathoms continue to measure line lengths for practical applications, such as setting lure depths to target pelagic species. Anglers often deploy lines to 20 to 60 fathoms (120 to 360 feet) to position lures along underwater contours where fish like wahoo congregate, using weighted rigs or downriggers calibrated in fathom increments for precision.^[46] Regulatory frameworks, such as those in California, define fishing zones by 50-fathom depth contours, indirectly influencing line lengths to comply with groundfish conservation areas while optimizing catch rates.^[47]

Burial Practices

In maritime tradition, burial at sea during the 19th century often occurred at a minimum depth of 6 fathoms (36 feet) to ensure the body remained submerged and undisturbed, a practice rooted in naval customs to prevent floating remains from resurfacing. This depth requirement, reflected in the phrase "deep six," served as a rule of thumb in naval law and contributed to the unit's cultural significance beyond measurement.^[48] Cultural and religious contexts emphasized ritual to honor the deceased while addressing seafaring superstitions, such as fears of restless spirits haunting the vessel. Bodies were typically weighted with cannonballs, shot, or iron shackles attached to the feet and sewn into canvas hammocks or sailcloth shrouds by fellow sailors, ensuring descent to the specified depth without interference from currents.^[49] Christian services adapted from land funerals were common, featuring prayers like "I am the resurrection and the life" read from the Book of Common Prayer, with the body committed to the deep amid solemn rites to provide spiritual closure at sea.^[50] Historical examples from whaling ships illustrate these practices vividly; on 19th-century vessels like the Continental, deceased crew members were dressed in shore clothes, weighted, and slid from a plank during brief ceremonies, as recounted in sailor accounts emphasizing communal mourning.^[49] In literature, Herman Melville's depictions in works such as White-Jacket (1850) portray similar rituals, where weighted bodies were consigned to fathom-deep waters, underscoring the emotional bonds and superstitions among whalemen far from home.^[51] The Seamen's Bethel in New Bedford, established in 1832, commemorates such losses through plaques honoring drowned whalers, reflecting the prevalence of these customs in the industry.^[49]

Land and Surveying Uses

In the 18th and 19th centuries, the fathom found application in land surveying as part of the imperial measurement system, where it served as a reference for longer units like the Gunter's chain, a primary tool for measuring distances in fieldwork. The Gunter's chain, introduced in 1620 by English mathematician Edmund Gunter, consisted of 100 iron links totaling 66 feet, which equated precisely to 11 fathoms based on the standard 6-foot fathom.^[52] This equivalence facilitated conversions during boundary delineation and property assessments, especially in British and American colonial surveys where chains were the standard for linear measurements, with 10 chains forming a furlong and 10 square chains defining an acre. Surveyors often carried chains calibrated against fathom-based rods (each rod being 16.5 feet or 2.75 fathoms), ensuring consistency in mapping expansive terrains for agriculture and settlement.^[53] The fathom's utility extended to mining operations on land, where it was commonly employed to denote vertical depths of shafts and levels, reflecting its origins in practical, arm-span measurements adaptable to underground environments. In Cornish mining, a hub of 19th-century copper and tin extraction in England, depths were routinely reported in fathoms; for instance, the Dolcoath Mine, one of the deepest in the region, reached 412 fathoms by the late 1800s, with shafts extending over 2,160 feet and extensive tunnel networks.^[54] Similarly, in the United States, early 19th-century zinc and lead mines in Pennsylvania utilized fathoms for depth records. At the Wheatley Mines near Phoenixville, shafts were sunk to depths such as 50 fathoms by 1854, with levels connected by adits and whim shafts reaching 39 fathoms, aiding in ore extraction planning and safety assessments during the industrial expansion.^[27] These practices persisted into the early 20th century in some operations, providing a standardized metric for geologists and engineers evaluating seam thicknesses and structural stability.

References

[1]
Definition of FATHOM
### Summary of "Fathom" as a Noun Unit of Measurement
[2]
[PDF] General Information - NOAA Nautical Charts
Sep 28, 2025 · 1:10,000 scale chart is equal to 10,000 of the same unit on the earth's surface. ... fathom scale indicates 15 fathoms when the depth is 415.
[3]
NIST Guide to the SI, Appendix B: Conversion Factors
Feb 1, 2016 · Where less than six digits after the decimal place are given, the unit does not warrant a greater number of digits in its conversion.
[4]
Fathom - Etymology, Origin & Meaning
Originating from Old English fæðm, meaning "arms, embrace" and a measure of about six feet, from Proto-Germanic *fathmaz, "embrace." The verb form means "to ...Fathom(n.) · Fathom(v.) · Entries Linking To FathomMissing: span | Show results with:span
[5]
What do the numbers mean on a nautical chart?
Jun 16, 2024 · A fathom is a nautical unit of measurement and is equal to six feet . On a chart, water depths may be connected with a line known as a depth ...
[6]
FATHOM Definition & Meaning - Dictionary.com
to measure the depth of by means of a sounding line; sound. to penetrate to the truth of; comprehend; understand. to fathom someone's motives.
[7]
The history of measurement - MacTutor - University of St Andrews
The Greeks used as their basic measure of length the breadth of a finger (about 19. 3 mm), with 16 fingers in a foot, and 24 fingers in a Greek cubit.
[8]
What is the unit called a meh?
In ancient Egypt, a unit of length, about 52.5 centimeters. ... This unit is often called the “royal ell" or "royal cubit". Also romanized as mḥ. Marshall Clagett ...
[9]
What is the unit called an orguia?
In classical times, a unit of length, in concept the distance between the tips of the fingers of the outstretched arms (like a fathom), = 6 pous.
[10]
[PDF] A Brief History of Some Common American Units of Length and Weight
Fathom was their word for embrace. It was either approximately or exactly two ells, depending on the definition of the ell. The fathom was also approximately ...
[11]
Units of Measurement from Viking Age Law and Literature
Length/Distance. Old Norse Measurement, Equivalent To, Description. faðmr, about 2 yards in length, A measure of length, a "fathom". Also means "the out- ...
[12]
Meaning and Origin of Nautical Terms
Dec 4, 2017 · Although a fathom is now a nautical unit of length equal to six feet, it was once defined by an act of Parliament as "the length of a man's arms ...<|separator|>
[13]
None
Below is a merged summary of fathom usage in Columbus's Journal, consolidating all information from the provided segments into a single, dense response. To maximize detail and clarity, I’ve organized the key data into tables where appropriate, followed by a narrative summary for additional context. The response retains all examples, indications of length or inconsistency, and useful URLs mentioned across the segments.
[14]
Deprecation of the United States (U.S.) Survey Foot - Federal Register
Oct 5, 2020 · ... definition of one foot being equal to 0.3048 meter (exactly). This definition was named the “international foot” in the 1959 Federal ...
[15]
None
Below is a merged response summarizing the standardization information for "fathom" from the IHO S-4 (Edition 4.9.0, March 2021) document. To retain all details efficiently, I’ve organized the information into a dense table format in CSV style, followed by a concise narrative summary. This approach ensures all data from the individual segments is preserved while maintaining clarity and structure.
[16]
978-1-349-86203-0.pdf
the Weights and Measures Act, 1856, and a precise definition of the unit, the Imperial Standard Yard, was given by the Act of. 1878, of the same title ...
[17]
[PDF] Conversion tables for research workers in forestry and agriculture
6 feet = l fathom (fath.) 5-j yards = 1 pole, rod, perch. 22 yards = 1 chain (ch.) 7-92 inches = 1 link (lk.) 100 links = 1 chain. 10 chains = 1 furlong (fur ...
[18]
Deprecation of the United States (U.S.) Survey Foot - Federal Register
Oct 17, 2019 · The 1959 notice was issued after an international agreement among ... The notice defined this international foot as 0.304 8 meter ...
[19]
New Year's Eve 2023 Marked the Retirement of the U.S. Survey Foot
Jan 6, 2023 · ... foot,” while the foot definition adopted in 1959 was called the “international foot.” At the time, it was mandated that the U.S. survey foot ...
[20]
Fisheries Glossary - Voices of the Bay - National Marine Sanctuaries
Fathom A nautical unit of measurement. One fathom equals 6 feet or 1.83 meters. Federal Register The official daily publication for Rules, Proposed Rules ...
[21]
[PDF] The Perkiomen and Wheatley Mines
A steam engine was erected here but no record of it exists and the engine shaft was only sunk to a depth of fifteen fathoms with a single level driven two ...
[22]
Pit Terminology - Healey Hero
Fathom - Unit of length, 6 feet, used for depths of shafts or seams. Fault - A slip or strata displacement. Break in the continuity of a coal seam. Feather ...
[23]
Understanding Depth Limits in the Recreational Groundfish Fishery
May 31, 2017 · In the other groundfish management areas, fishing is allowed in deeper depths – out to 30 or even 60 fathoms in the Southern Management Area.
[24]
Summary of Recreational Groundfish Fishing Regulations
20 Fathom - Inshore Only Take is prohibited seaward of the 20 fathom (120 feet) boundary line ... Divers and shore-based anglers are exempt from season and depth ...<|control11|><|separator|>
[25]
The Nautical Mile | Proceedings - November 1949 Vol. 75/11/561
The fathom was used anciently as a measure of the outstretched arms, from which the term is derived. Another and longer unit widely used was the league, which ...Missing: journals | Show results with:journals
[26]
league, n.¹ meanings, etymology and more | Oxford English Dictionary
marine league noun a unit of distance = 3 nautical miles or 3041 fathoms. Although the league appears never to have been an English measure, leuca occurs ...
[27]
Knots, Fathoms, and Gales: Nautical Measurement Terms to Know
though that ...<|control11|><|separator|>
[28]
Convert Fathom to Nautical Mile (international) - Unit Converter
1 fath = 0.000987473 nautical mile (international) 1 nautical mile (international) = 1012.6859142607 fath
[29]
Anchors, Chains, and Stoppers | Naval History Magazine
Navy anchor chain comes in 15-fathom (90-foot) lengths called shots. Individual shots are connected to one another by detachable links, and a special color ...
[30]
Imperial Measures of Length
Fathoms measure depth of water. They have been in use in England since before 1600, and may be derived from faethm, the Anglo Saxon word for 'to embrace' ( ...
[31]
Ask Us - Knots and the Nautical Mile - Aerospaceweb.org
Aug 31, 2003 · The official US Navy sand glass measured 28 seconds and the knots on the rope were spaced exactly 48 feet apart, equal to eight fathoms.
[32]
British-American System of Units - The Physics Hypertextbook
A standard yard is 3 feet long. Since the International Yard and Pound Agreement of 1959, the yard has been defined as exactly 914.4 mm.
[33]
Leadline - National Maritime Historical Society
Since the 5th century BCE, the leadline has been used to both measure the depth of the water and determine the characteristics of the sea floor. Lead Line ...
[34]
History of Hydrographic Surveying - NOAA Nautical Charts
The 1930s saw the development and implementation of single-beam echo sounders that used sound to measure the distance of the sea floor directly below a vessel.Missing: International 1920s
[35]
Lead Line - Navigation
Sounding Lead, 7 lbs., marked in 25 fathom increments (156 feet) · It began with the oldest known boat trading peoples, the Egyptians. · The earliest device to ...
[36]
Captain Cook's Journal During the First Voyage Round the World
... Depth increased to 30 fathoms, at Noon in 36 fathoms. Latitude Observed 22 ... Soundings 75 fathoms. Saw some Penguins. Gave to each of the People a ...Chapter 3. Tahiti · Chapter 6. Exploration Of... · Chapter 8. Exploration Of...<|control11|><|separator|>
[37]
Glossary of Nautical Measures – Lengths - Hemyock Castle
A cable is about 101 fathoms, a fathom is 6 feet, a nautical mile is 1852 meters, and a nautical league is 3 nautical miles.
[38]
Sea Mile Nautical Measurements Cable Fathom Chain
Jun 27, 2019 · Cable's Length (distance): Tenth of a nautical mile (approx 101 fathoms). Cable-laid cable: 100 to 115 fathoms. Cablet: 120 fathoms. Hawser ...
[39]
The Use Of Anchors In Maneuvering - U.S. Naval Institute
It sometimes happens, when this occurs, that 30 or more fathoms of chain can be paid out without having as much effect as the 15 fathoms originally had. (d) ...Missing: practices | Show results with:practices
[40]
The Best Depth for Wahoo Fishing | In The Spread
Mar 6, 2025 · Many experienced anglers target wahoo on contours in 20-60 fathoms (120-360 feet). These statistics highlight that while wahoo can dive to ...
[41]
Ocean Sport Fishing - California Department of Fish and Wildlife
Groundfish Management Areas: Federal latitude/longitude coordinates defining the West Coast 50-fathom depth contours and other West Coast depth contours ...San Francisco Region · In-Season Ocean Fishing... · General Ocean Fishing Regs
[42]
Navy fighter pilot terms - Blue Ridge Journal
The "deep-six" phrase apparently derives from the depth reading of 6 fathoms (36 feet), specified as the minimum depth for burial at sea by naval law.
[43]
Burial at Sea - Naval History and Heritage Command
Jun 10, 2024 · For at sea disposition, the casketed remains are covered with the national ensign with the union placed at the head and over the left shoulder.Missing: fathoms | Show results with:fathoms
[44]
Interment without Earth: A Study of Sea Burials during the Age of Sail
Nov 26, 2010 · Sea burials evidenced the heightened superstitions and emotional bonds of sailors and their need to both honor and protect themselves from the spirits of their ...
[45]
Sailors' Funerals - British Tars, 1740-1790
Aug 6, 2018 · ' He suggests that part of the reason for burial at sea may have been sailors fear of their shipmates 'body haunting the ship.'[15] On the ...
[46]
mourning — Whaling History Essays — Silas J. Costello
Jan 3, 2024 · Burials at sea were the most common. For a burial at sea the man would be dressed in his shore clothes. Then he'd be sewn up in canvas and ...
[47]
Convert chain [Gunter, survey] to fathom - Conversion of ...
Do a quick conversion: 1 chains = 11.000022000044 fathoms using the online calculator for metric conversions. Check the chart for more details.
[48]
History of Surveying
In the 18th and 19th centuries the art of surveying advanced more rapidly. ... Gunter's Chain. The transit and tape permitted more precise measurements ...
[49]
Dolcoath Mine Stope Collapse - Camborne - 1893
The 412 fathom level was the deepest that had been opened in this mine, although the shaft is down far enough for the 425 fathom levels. The lode at the site of ...
[50]
Fathom - Math.net
A fathom is a unit of length in the US customary and imperial systems of measurement equal to 6 feet or 1.8288 meters.