Dictionary term
Dead Reckoning
Direct answer
Dead Reckoning is the process of advancing a known position using courses steered, speeds, and elapsed time.
Dead Reckoning is a course-and-speed position estimate used in historical astronomy, timekeeping, or navigation.
Dead Reckoning is a course-and-speed position estimate used in historical astronomy, timekeeping, or navigation.
An engraved functional orientation; the page explains the real instrument, method, or publication.Quick reference
- Use when
- Use Dead Reckoning by logging every course, speed, time interval, and known correction for current, leeway, or maneuver.
- Do not use it for
- Unmeasured current, wind, steering error, and log error accumulate with time, so the result is not a fix.
- Reference category
- Historical Almanacs & Instruments
- Related terms
- Pelorus, Celestial Navigation, Latitude by Meridian Altitude, Longitude by Chronometer
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The story behind Dead Reckoning
Dead reckoning long predates electronic navigation and was often recorded with logs, glasses, and traverse boards.
Dead Reckoning in spiritual tradition
Dead Reckoning rewards careful observation, explicit assumptions, and humility about the limits of every model or measurement.
Dead Reckoning: fact and faith, kept distinct
This is a factual history-of-science, instrument, timekeeping, or navigation reference. It may support wonder and disciplined attention without becoming a claim of fate, worship, or private revelation.
Dead Reckoning in numerology
Dead Reckoning is not a numerology claim. Any numbers attached to it should retain their ordinary scientific, calendrical, navigational, or historical meaning unless a separate symbolic interpretation is clearly labeled.
Why Dead Reckoning matters
Dead Reckoning matters because it supplies a continuous estimate between external fixes and a starting point for sight reduction.
Dead Reckoning at work: an example
A vessel travels 10 nautical miles on a true course and plots that displacement from the last fix.
Where interpretation stops
Dead Reckoning is presented as sourced astronomy, calendrical, Earth-science, cultural, or instrument-history reference. Definitions should distinguish measured phenomena from civil convention and historical interpretation, preserve location and time dependencies, and avoid turning factual sky data into a deterministic personal claim.
Sources and editorial method
Research references used for this entry include:
- National Geospatial-Intelligence Agency: The American Practical Navigator - Official modern reference for navigation principles, celestial observations, sight reduction, and navigational tables.
- Royal Museums Greenwich: Traverse Board - Museum documentation of the peg board used to record a vessel's course and speed by watch.
- Source
- The Great Almanac Dictionary
- Category
- Historical Almanacs & Instruments
- Also appears in
- Historical Almanacs & Instruments
- Aliases
- None listed
- Last updated
- 2026-07-16
Explore Dead Reckoning
Dead Reckoning in a book is one thing; Dead Reckoning in your own birth chart is your life. The Oracle casts your real chart and tells you what it means for your love, your work, and your year ahead, in conversation, free.
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More in Historical Almanacs & Instruments
- Gunter's Quadrant
- Lunar Distance Method
- Planisphere
- Semidiameter Correction
- Transit Table
- Assumed Position
- Celestial Globe
Common questions
What is Dead Reckoning?
Dead Reckoning is the process of advancing a known position using courses steered, speeds, and elapsed time.
How is Dead Reckoning used in an almanac?
Use Dead Reckoning by logging every course, speed, time interval, and known correction for current, leeway, or maneuver.
What should I avoid when interpreting Dead Reckoning?
Unmeasured current, wind, steering error, and log error accumulate with time, so the result is not a fix.
