Ship's Watches to Days (watch to d)
1 ship's watch equals 0.1666666667 days (rounded).
How to convert ship's watches to days
To convert ship's watches to days, multiply the number of ship's watches by 0.1666666667. The factor is rounded to 10 significant digits. To go the other way, multiply days by 6.
days = ship's watches × 0.1666666667
Example: 10 ship's watches = 1.666666667 days.
Months and years are not constant. This site uses the average Gregorian year of 365.2425 days, so one 'year' converts to 365.2425 days, not 365; use 'common year' for exactly 365 days.
About these units
Ship's Watch (watch)
Four hours, the standard duty period at sea. The 'dog watches' of the evening are split into two hours each.
Naval and merchant crews divide the day into watches so that the ship is never left unattended. A normal watch lasts four hours, and its length is the basis for the figure used here, 14,400 seconds. The traditional scheme described by Wikipedia had five four-hour watches and two two-hour dog watches, named the first, middle, morning, forenoon and afternoon watches, with the afternoon watch ending at 1600.
Splitting the 1600 to 2000 period into a first and second dog watch gives an odd number of watches per day, so each crew member's schedule shifts from day to day, and it also lets everyone eat an evening meal. Time on board is marked with the ship's bell, struck every half hour so that eight bells ends a four-hour watch. Merchant ships typically keep six four-hour watches instead, which makes the pattern consistent.
1 ship's watch = 14,400 seconds (exactly).
Sources: Wikipedia: Watchkeeping; Wikipedia: Ship's bell
Day (d)
24 hours or 86,400 seconds. The mean solar day; the actual rotation of the Earth is about 4 minutes shorter (see sidereal day).
Old English dæg is the root of our day, with close cousins in German Tag, Dutch dag and Icelandic dagur, all descending from Proto-Germanic dagaz. It is the oldest unit here, because the cycle of light and dark needs no instrument. Yet the day we count is a constructed average: the actual interval from one noon to the next varies through the year by up to about 7.9 seconds, because Earth's orbit is elliptical and its axis is tilted.
Astronomers smooth this out with a fictitious mean Sun, giving the mean solar day, and the day in the SI sense is fixed at exactly 86,400 seconds. Reality has drifted slightly: the mean solar day has recently averaged about 86,400.002 seconds, and tidal drag from the Moon is lengthening it by about 2 milliseconds per century. That is why 27 leap seconds were added to UTC between 1972 and 2022. One rotation measured against the distant stars is shorter, about 23 hours 56 minutes 4.09 seconds, and a year contains one more of these sidereal days than solar days.
1 day = 86,400 seconds (exactly).
Sources: Wikipedia: Day; BIPM: SI Brochure, 9th edition
Related conversions
- Days to ship's watches (reverse)
- Ship's watches to seconds
- Ship's watches to minutes
- Ship's watches to hours
- Ship's watches to weeks
- Ship's watches to months
- Ship's watches to years
- Seconds to days
- Minutes to days
- Hours to days
- Weeks to days
- Months to days
- Years to days
- Milliseconds to days
- Microseconds to days
- Nanoseconds to days
- Decades to days
- Centuries to days
- Millennia to days
See all time units.