land speed is measure in km/h, but for some other
- Thread starter skrops
- Start date
WIKIPEDIA TO THE RESCUE!!!!!
1 international knot =
1 nautical mile per hour (exactly),
1.852 kilometres per hour (exactly),[6][/suP]
0.514 meters per second,
1.15077945 miles per hour (approximately).
1.852 km is the length of the internationally-agreed nautical mile. The U.S. adopted the international definition in 1954, having previously used the U.S. nautical mile (1,853.248 m).[7][/suP] The U.K. adopted the international nautical mile definition in 1970, having previously used the U.K. Admiralty nautical mile (6,080 ft [1,853.184 m]).
The speeds of vessels relative to the fluids in which they travel (boat speeds and air speeds) are measured in knots. For consistency, the speeds of navigational fluids (tidal streams, river currents and wind speeds) are also measured in knots. Thus, speed over the ground (SOG) (ground speed (GS) in aircraft) and rate of progress towards a distant point ('velocity made good', VMG) are also given in knots.
ORIGIN: Until the mid-19th century vessel speed at sea was measured using a chip log. This consisted of a wooden panel, weighted on one edge to float upright and thus have substantial water resistance, attached by line to a reel. The chip log was "cast" over the stern of the moving vessel and the line allowed to pay out. Knots placed at a distance of 47 feet 3 inches (14.4018 m) passed through a sailor's fingers, while another sailor used a 30 second sandglass (28 second sandglass is the current accepted timing) to time the operation.[8][/suP] 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. The difference from the modern definition is less than 0.02%.
1 international knot =
1 nautical mile per hour (exactly),
1.852 kilometres per hour (exactly),[6][/suP]
0.514 meters per second,
1.15077945 miles per hour (approximately).
1.852 km is the length of the internationally-agreed nautical mile. The U.S. adopted the international definition in 1954, having previously used the U.S. nautical mile (1,853.248 m).[7][/suP] The U.K. adopted the international nautical mile definition in 1970, having previously used the U.K. Admiralty nautical mile (6,080 ft [1,853.184 m]).
The speeds of vessels relative to the fluids in which they travel (boat speeds and air speeds) are measured in knots. For consistency, the speeds of navigational fluids (tidal streams, river currents and wind speeds) are also measured in knots. Thus, speed over the ground (SOG) (ground speed (GS) in aircraft) and rate of progress towards a distant point ('velocity made good', VMG) are also given in knots.
ORIGIN: Until the mid-19th century vessel speed at sea was measured using a chip log. This consisted of a wooden panel, weighted on one edge to float upright and thus have substantial water resistance, attached by line to a reel. The chip log was "cast" over the stern of the moving vessel and the line allowed to pay out. Knots placed at a distance of 47 feet 3 inches (14.4018 m) passed through a sailor's fingers, while another sailor used a 30 second sandglass (28 second sandglass is the current accepted timing) to time the operation.[8][/suP] 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. The difference from the modern definition is less than 0.02%.
skrops wrote:
You need to take all variables in consideration.
Variable 1 - a current flowing from 10 points north of the starboard side to 40 degrees of the port side with a vector speed of 12 knots gusting 22.
The craft is a double hulled, with 2 x 80 hp engines.
Skipper wants to travel in a north westerly direction to a spot 15 nautical miles offshore.
How long will it take the skipper to reach ???
Well, considering that no1. the craft is a double hull sporting 2 x 80hp engines, he can plane at double the speed od a mono hull craft with 1 x 40 hp engine !
The fact that the wind speed is off port ( as explained in variable 1) means that it is going to take longer than if the wind was coming from behind, however we need to take into consideration that there is a gust of 22 knots, it wmeans that at intervals, you will be travelling even slower.
Bottom line, You gonna get there !
You going fishing, who cares if it takes longer !
Stop your whining, crack another beer, and prepare your tackle !
Hope this helps
You need to take all variables in consideration.
Variable 1 - a current flowing from 10 points north of the starboard side to 40 degrees of the port side with a vector speed of 12 knots gusting 22.
The craft is a double hulled, with 2 x 80 hp engines.
Skipper wants to travel in a north westerly direction to a spot 15 nautical miles offshore.
How long will it take the skipper to reach ???
Well, considering that no1. the craft is a double hull sporting 2 x 80hp engines, he can plane at double the speed od a mono hull craft with 1 x 40 hp engine !
The fact that the wind speed is off port ( as explained in variable 1) means that it is going to take longer than if the wind was coming from behind, however we need to take into consideration that there is a gust of 22 knots, it wmeans that at intervals, you will be travelling even slower.
Bottom line, You gonna get there !
You going fishing, who cares if it takes longer !
Stop your whining, crack another beer, and prepare your tackle !
Hope this helps