When you are talking about ships, how much does a knot equal?

Question

How many piles an hour does a knot equal? Thanks!

MILES per hour. EXCUSE me. **rolls eyes** picky, picky.

Answer 1

In case that you are wondering where the name came from, sailors used to tie "knots" in a rope, tie one end of the rope to a log, let the log trail behind the ship, and then toss something floating overboard and watch it drift past the knotted rope.

Count the number of knots in the rope that the drifting thing past in a certain amount of time, and you know how many "knots" that you were going.

A knot is one nautical mile per hour.

One nautical mile is 1.15 land miles, so a knot is 1.15 miles per hour.

A variation in the technique that I described above, is given below. I think that this second technique was more common since it used fewer floating things 9but still a knotted rope):
--------------------------
The device that sailors used to make their speed measurement was called the "chip log". Chip as in chip of wood, and log as in to record in a log. The chip was a wedge of wood about 18" in size; it was tied to one end of a rope on a large spool. The rope had knots tied into it about every 47'3" (more about how that was calibrated below).

The wooden chip was thrown overboard at the ship's stearn (back end). Because of its wedge shape, it would "grab" the water and start pulling out rope as the ship moved forward at some yet unknown speed. One man would hold the spool of rope as it played out; another man would start a sandglass filled with 30 seconds of sand; and a third man would count the knots as they passed over the stearn board. When the 30 seconds of sand expired, the time keeper would call out and the counting of knots would stop.

The number of knots in the rope that were counted in 30 seconds was then equal to the speed of the ship in nautical miles per hour. A "knot", therefore, is not a nautical mile; it is a nautical mile per hour. Thus 1 knot was equivalent to 1 nautical mile per hour; 5 knots were equivalent to 5 nautical miles per hour; etc. The similar sound of "knot" and "naut" is entirely coincidental.

Answer 2

Above definition is incorrect. A nautical mile is an angular measurement, not a linear distance. One nautical mile is equal to one minute of arc along a great circle. There are 60 nm in one degree of a great circle. A great circle is spherical plane passing through the center of a sphere. Lines of longitude are all great circles. Lines of latitude are not. Sailors use spherical geometry to navigate. One knot is the speed at which a vessel transverses one minute of arc per one hour. If a boat could travel straight up at 50 mph, it's speed in knots would be zero since no angular motion takes place.

Answer 3

A knot equals a nautical mile. and is equal to 1.15 statute miles n hour.The term comes from a knotted line thrown over the side to determine speed. A nautical mile is equal to one minute of latitude, making determining position easier.

Answer 4

A knot is a unit of speed, abbreviated kt or kn. It is a non-SI unit accepted for use with the SI.[1] It is used around the world for maritime and aviation purposes.

Contents [hide]
1 Definition
2 Conversions
3 Origin
4 Discussion
4.1 Nautical examples
5 Aeronautical terms
6 External links
7 See also
8 References



[edit]
Definition
1 knot = 1 nautical mile/hour = 1.852 km·h−1 exactly. This is based on the internationally agreed length of the nautical mile, as adopted by the US in 1954, the UK in 1970 and other countries. This is the definition used in most, if not all, modern circumstances. Knot is sometimes mistakenly used to refer to the nautical mile itself, but this is incorrect.

The speed of a vessel relative to the fluid itself, and not land, is referred to as 'boat speed' or, for aircraft, 'air speed' and is usually measured in knots. If the medium is flowing, this differs from the ground velocity by the velocity of the medium. Velocity made good refers to ground velocity and may also be expressed in knots in navigation.

[edit]
Conversions
1 knot is roughly equivalent to:

101.268591 foot/minute
1.687810 foot/second
0.5144444 metres per second (m·s−1)
1.852 kilometres per hour (km·h−1) (exact)
1.150779 mile (statute)/hour (mph)
[edit]
Origin
In some sailing ships, speed was measured by casting the chip log from the stern. The log was relatively immobile, and attached by line to a reel. Some sources suggest that knots placed at a distance of 47 feet 3 inches (14.4018 m) passed through a sailor's fingers, while another used a 28 second sandglass to time the operation. The knot count would be reported and used in the sailing master's dead reckoning and navigation. This method gives a value for the knot of 20.25 in/s, or 1.85166 km·h−1. The difference from the accepted value today is a bit less than 0.02 %.

[edit]
Discussion
Because a knot is defined as a nautical mile/hour, the expression "knots per hour" is considered incorrect as a unit of speed, since this suggests 'nautical mile/hour2', which would be a measure of acceleration.

Although knots do not fit within the primary SI system, their retention for nautical and aviation use is important for navigational reasons, since the length of a nautical mile is almost identical to a minute of latitude. As a result, distance in nautical miles on a navigational chart can easily be measured by using dividers and the latitude indicators on the side of the chart.

[edit]
Nautical examples
Displacement hulls (for example those not planing on the surface of the water) have a maximum speed beyond which they tend to 'dig in', with their bows high and sterns low, and become increasingly wasteful of propulsive power. This is known as their hull speed and it depends mainly upon waterline length. For normally-shaped boat hulls the following table relates waterline lengths to hull speeds and so gives some examples of usage of the unit knots.

Hull speeds Waterline length (ft) Waterline length (m) Hull speed (knots) Comment
10 3.0 4.4 Dinghy
18 5.5 5.9 Small fishing or pleasure boat
28 8.5 7.3 Small yacht
36 11.0 8.2 Family yacht
50 15 9.8 Small commercial fishing boat or ferry
200 61 20 Small commercial ship
400 122 28 Typical cruise or container ship

Answer 5

Getting confuse yet? On land the unit of speed is either called mph or kph (miles or kilometers per hour). At sea, it's called knots or nautical miles per hour.
Land one mile is equal to 5280 feet.
Sea one nautical mile is equal to 6078 feet. See the difference?
798 feet.

Answer 6

One Knot equals one nautical mile per hour.

Go here for more information:
http://www.onlineconversion.com/faq_07.htm

Hope this helps!

Answer 7

1 knot= 1.15mph.

Answer 8

a statute mile is 5280 feet. a nautical mile is 6078 feet. 1.15 miles =1 knot

Answer 9

I believe a knot is equivalent to 1.5 mph.

Answer 10

1 knot is roughly equivalent to:

101.268591 foot/minute
1.687810 foot/second
0.5144444 metres per second (m·s−1)
1.852 kilometres per hour (km·h−1) (exact)
1.150779 mile (statute)/hour (mph)