I have noticed that many inland sailors use knots when referring to speed, on inland waters don't you use miles per hour?
Knots or Miles Per Hour
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Don't think it matters a lot
But if you are going to navigate knowing your speed in knots is very important at sea. Each minute of latitude equals one nautical mile. So if you head off into the horizon to a place say 100 nautical miles away and your estimated average speed is 6 knots it will take about 17 hours to get there. So I would imagine that most large inland lakes over there would have charts.
But if you are going to navigate knowing your speed in knots is very important at sea. Each minute of latitude equals one nautical mile. So if you head off into the horizon to a place say 100 nautical miles away and your estimated average speed is 6 knots it will take about 17 hours to get there. So I would imagine that most large inland lakes over there would have charts.
I don't, to answer your question.
Distances on the intra coastal are measured in Statute miles but I have the ability to set my chartplotter to Nautical miles so my speed is accurately referenced in Knots. It saves having to change my frame of mind as I may enter and exit the Intra coastal. Planned a trip foe Lake Eire and did the calculations in MPH but converted the results to Knots to make it easier to visualize.
Distances on the intra coastal are measured in Statute miles but I have the ability to set my chartplotter to Nautical miles so my speed is accurately referenced in Knots. It saves having to change my frame of mind as I may enter and exit the Intra coastal. Planned a trip foe Lake Eire and did the calculations in MPH but converted the results to Knots to make it easier to visualize.
Ditto, Lakesend
I noticed that my charts for Lake Champlain were in statute miles & thought it was just plain wrong. As Lakesend notes above, if you're on a boat, it's knots. MPH is for highway driving! Does anyone know why this silly dicotomy exists?
I noticed that my charts for Lake Champlain were in statute miles & thought it was just plain wrong. As Lakesend notes above, if you're on a boat, it's knots. MPH is for highway driving! Does anyone know why this silly dicotomy exists?
Knots vs Miles per hour
I was taught to use statute miles and mph inland. Use nautical miles and knots at sea. All my Great Lakes charts have a statue mile scale at the bottom. I often use the scale in calculation distance and speed.
I was taught to use statute miles and mph inland. Use nautical miles and knots at sea. All my Great Lakes charts have a statue mile scale at the bottom. I often use the scale in calculation distance and speed.
If you're measuring movement of a vessel
through a fluid, knots is the internationally accepted measure -- for both boats and aircraft. Powerboaters use statute miles because it makes their boats sound faster. /Eric Foxfire
through a fluid, knots is the internationally accepted measure -- for both boats and aircraft. Powerboaters use statute miles because it makes their boats sound faster. /Eric Foxfire
The basis is...
A degree of Latitude is one nautical mile. That helps in nautical navigation. Thats why boats are supposed to use nautical miles. Why charts use st. miles just slays me. I convert to NM then recalc everything in NM's
A degree of Latitude is one nautical mile. That helps in nautical navigation. Thats why boats are supposed to use nautical miles. Why charts use st. miles just slays me. I convert to NM then recalc everything in NM's
Why statute miles anyway?
With all due respect, Jack, if I'm not mistaken -- and I'm sure you just didn't write it down correctly -- it's a *minute* of latitude, not a degree. A degree would be 60 NM. I wonder why statute miles were ever "invented?" With such an elegant basis as linkage to latitude, why a more arbitary distance such as 5,280' was ever settled on seems an oddity. For my part, I can never even remember that number & had to look it up to write it here. Guess since landlubbers far outnumber mariners, the majority ruled!
With all due respect, Jack, if I'm not mistaken -- and I'm sure you just didn't write it down correctly -- it's a *minute* of latitude, not a degree. A degree would be 60 NM. I wonder why statute miles were ever "invented?" With such an elegant basis as linkage to latitude, why a more arbitary distance such as 5,280' was ever settled on seems an oddity. For my part, I can never even remember that number & had to look it up to write it here. Guess since landlubbers far outnumber mariners, the majority ruled!
Blame the British
I answered my own question after a look at Wikipedia: "A unit of distance called a mile was first used by the Romans and denoted a distance of 1,000 paces (one pace is two steps, 1,000 paces being, in Latin, mille passus) or 5,000 Roman feet, and corresponded to about 1,480 meters, or 1,618 modern yards. "The current definition of a mile as 5,280 feet (as opposed to 5,000) dates to the 13th century, and was confirmed by statute in the reign of Queen Elizabeth I; the change was needed to accommodate the rod which (as opposed to the mile) was a measure ensconced in legal documents (see the discussion about furlongs). "The Statute Mile is the distance typically meant when the word mile is used without other qualifying words (e.g. Nautical Mile, see below). "It originates from a Statute of the English parliament in 1592 during the reign of Elizabeth I. This defined the Statute Mile as 5,280 feet or 1,760 yards; or 63,360 inches. The reason for these rather irregular numbers is that 5,280 feet is made up of eight furlongs (the length generally that a furrow was ploughed before the horses were turned, furlong = furrow-long). In turn a furlong is ten chains (a surveyor's chain, used as such until laser range finders took over); a chain is 22 yards and a yard is three feet, making up 5,280 ft. Twenty-two yards is also the length of a cricket pitch, a game originating in England and played today particularly in countries that were once part of the British Empire." Eventually we'll all be using KM anyway, no!?!
I answered my own question after a look at Wikipedia: "A unit of distance called a mile was first used by the Romans and denoted a distance of 1,000 paces (one pace is two steps, 1,000 paces being, in Latin, mille passus) or 5,000 Roman feet, and corresponded to about 1,480 meters, or 1,618 modern yards. "The current definition of a mile as 5,280 feet (as opposed to 5,000) dates to the 13th century, and was confirmed by statute in the reign of Queen Elizabeth I; the change was needed to accommodate the rod which (as opposed to the mile) was a measure ensconced in legal documents (see the discussion about furlongs). "The Statute Mile is the distance typically meant when the word mile is used without other qualifying words (e.g. Nautical Mile, see below). "It originates from a Statute of the English parliament in 1592 during the reign of Elizabeth I. This defined the Statute Mile as 5,280 feet or 1,760 yards; or 63,360 inches. The reason for these rather irregular numbers is that 5,280 feet is made up of eight furlongs (the length generally that a furrow was ploughed before the horses were turned, furlong = furrow-long). In turn a furlong is ten chains (a surveyor's chain, used as such until laser range finders took over); a chain is 22 yards and a yard is three feet, making up 5,280 ft. Twenty-two yards is also the length of a cricket pitch, a game originating in England and played today particularly in countries that were once part of the British Empire." Eventually we'll all be using KM anyway, no!?!
Use what works
If your inland course has mile markers then you should/can switch your unit to read miles. At sea you can use either but knots and NM make the math easier when reducing a sighting with your sextant or estimating how far you will go with your fingers. It really does not matter if you use NM, SM, km or furlongs/fortnight. They all have their uses and the choice revolves around ease of use.
If your inland course has mile markers then you should/can switch your unit to read miles. At sea you can use either but knots and NM make the math easier when reducing a sighting with your sextant or estimating how far you will go with your fingers. It really does not matter if you use NM, SM, km or furlongs/fortnight. They all have their uses and the choice revolves around ease of use.
VT ..Yep my mind was in minutes...
my fingers were in degrees..One MINUTE of Lat is One nautical miles..Geesh, even my fingers mis-speak
But we still haven't assertained why the ICW charts which were created much later than 1592 use SM instead of NM.
my fingers were in degrees..One MINUTE of Lat is One nautical miles..Geesh, even my fingers mis-speak
But we still haven't assertained why the ICW charts which were created much later than 1592 use SM instead of NM.
Missing Land Marks
It appears to me: In times past, in open water, the only way to mark miles is minutes of latitude, hence the use of knots. On land, where the horizon is less accessible, as are navigational tools, statute miles are used. Inland waters, the same inability to see the "true" horizon and use a sextant still holds. Therefore, inland waters = statute miles.
It appears to me: In times past, in open water, the only way to mark miles is minutes of latitude, hence the use of knots. On land, where the horizon is less accessible, as are navigational tools, statute miles are used. Inland waters, the same inability to see the "true" horizon and use a sextant still holds. Therefore, inland waters = statute miles.
Inland and canal distances
Is it true that on inland canals (Erie, etc.) official distances are given in statute miles per hour and not knots? If so what other (inland) waterways are always in MPH?
Is it true that on inland canals (Erie, etc.) official distances are given in statute miles per hour and not knots? If so what other (inland) waterways are always in MPH?
Sextant is the reason
On the ocean you use a sextant to fix your position via latitude, one minute of latitude is a nautical mile, Knot. On land, you don't use a sextant, because you can't see the horizon. Mapping on land is a surveyor's job, they use different tools and statute miles. It is as simple as that. IMHO
On the ocean you use a sextant to fix your position via latitude, one minute of latitude is a nautical mile, Knot. On land, you don't use a sextant, because you can't see the horizon. Mapping on land is a surveyor's job, they use different tools and statute miles. It is as simple as that. IMHO
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