MPH Vs. Knots?

[shoefish]

Sorry Shoe but you are SO wrong!! Prior to taking the curvature of the frontal lobe at sea level and 40,000 feet you must first define the deviation of the left posterial tempural gyrus with the medial tempural lobe to get the triginomic factor. You cannot just multiply it by Pi or by 1.15 because the photoelectric effect could cause coupled hyperbolic-elliptic nonlinear partial differential equations. Therefore if you take the square root of the speed of light from a lighthouse and add it to the the difference between the curvature of the earth subtracted by 180 degrees and then plug this number into four-dimensional time-space continuum you end up with the correct answer. Got it?

I always forget about the hyperbolic-elliptic nonlinear partial differential equations.... I'm so STUPID.

[GWC3]

statute (ie, "land) mile is 5280 feet versus 6076 feet for a nautical mile. as stated earlier its a 1.15 conversion factor.

[unoyankeefan]

I think the main thing is when you read or are told to troll at a certain speed for a what you are looking for (in either knots or miles) is that you don't need to get hung up too much on be percise and use it as a starting point and then vary the speed up and down a little every five minutes or so until you get on the bite. We have often hooked up dropping the RPM's down or up a little and BAM! A hook up! I beleive that when the bite is cool, not only do you need to check your bait often, but changing up the speed some can start a bite that might not have happened.

[Captain Michael Buffington]

A nautical mile is longer due to the curvature of the earth. Water isn't flat and can't be graded like land can so it must follow the curve of the earth. Distances on the water should always be measured in nautical miles which like Avenger said can be measured by using a pair of dividers and 1 minute of latitude from your chart. It always bugs me when people say their boat goes X miles per hour referring to statute miles. I remind them that it would be the case if they were driving up the parkway but since most of us run our boats in the water, they need to use knots as their reference for speed. A boat running 30 miles per hour wouldn't get you to a wreck 30 miles offshore in an hour since those distances on a nautical chart are plotted in nautical miles... I think most magazines and boat manufacturers list speeds in mph just for marketing purposes so that people think they're getting faster boats...

curvature of da earth

Mike

[Bodie]

get a flux-capaciter

[Bligh]

In the sailing days 3 or 4 centuries ago they wanted to know how fast they were going so they had a rough Idea of how far they might make that day under that wind. They had a sand glass and a long piece of twine with knots tied in it at a specific distance. They also only new latitude and not longitude during most of that time. The head was only found on those big old sailing ships way up front , even infront of the bow railing on an over hang attached to the bow sprite sticking out front. These were wooden boxes with holes cut in the middle for pooping. Every where else on those big old sailing ships had tumblehome and the poopstains would be too much of a build up problem. But the bow head area managed to wash that area every couple days when it got rough. That is all the Wealth of useless knowledge I am sharing right now. So enjoy and keep bragging about knts over mph and remember a sand glass and a piece of twine with knots 3 centuries ago

[Storm]

In the sailing days 3 or 4 centuries ago they wanted to know how fast they were going so they had a rough Idea of how far they might make that day under that wind. They had a sand glass and a long piece of twine with knots tied in it at a specific distance. They also only new latitude and not longitude during most of that time. The head was only found on those big old sailing ships way up front , even infront of the bow railing on an over hang attached to the bow sprite sticking out front. These were wooden boxes with holes cut in the middle for pooping. Every where else on those big old sailing ships had tumblehome and the poopstains would be too much of a build up problem. But the bow head area managed to wash that area every couple days when it got rough. That is all the Wealth of useless knowledge I am sharing right now. So enjoy and keep bragging about knts over mph and remember a sand glass and a piece of twine with knots 3 centuries ago

And that is exactly how the term "poop deck" came to be. Although, still not sure what that has to do with knots vs. mph.

[N2theBlue]

In the ancient times, the only way to measure ship speed was to throw a wood log into the water and observe how fast it moves away from the ship. This approximate method of ship speed measurement was called 'Heaving the Log' and was used until 1500-1600s when the 'Chip Log' method was invented (both methods probably invented by Dutch sailors.)

The 'Chip Log' apparatus consisted of a small weighted wood panel that was attached to the reel of rope, and a time measuring device: a half-minute sand glass (as shown in image below to the right.) Rope had knots tied at equal distances along the reel. Sailors would throw the wood panel into the sea, behind the ship, and the rope would start unwinding from the reel. The faster the ship was moving forward the faster the rope would unwind. By counting the number of knots that went overboard in a given time interval, measured by the sand glass, they could tell the ship's speed. In fact that is the origin of the nautical speed unit: the knot.

Thats the origin of the name. The nautical mile is 1 minute of latitude along a meridian. 1 knot is 1 nautical mile/hour as a poster above stated.

[algdog]

I have one boat I fish on that uses mills per hour

figure that the boat traveling offshore with 6 passengers will
consume one miller light every 20 min or 1200 seconds
this means that a total of 18 miller lights are consumed per mill hour (21,600 seconds) enroute.
18 miller lights equates to 23 mph or 20knts for a conversion factor of 1.28 mills
so at cruising speed burning 18 miller lights per hour, at a conversion factor of 1.28 equates to a total speed ( makes no difference if the earth is flat or round after the first hour) of 20knts or we will get there when we get there

the mill factor does vary though, 18 mills per hour running offshore on a 24 hrs trip, you need a total reserve of 51,284 ounces to keep up to speed, yet at the end of the trip while trying to maintain mills the vessel will go faster with a higher conversion factor, because of the missing ounces in the boat
so a boat leaving the dock with a full load to run at 18 mills 20 knts will return at 18 mills while actually running 20.5 knts