Knots vs. MPH
- Thread starter pcator
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starcrafttom
Active member
I use mph ,not only because it drives my father crazy, but because I have used it all my life and cant think in knots. I would have to convert from one to another every time. It really does not matter as long as you know what your talking about.
A
Anonymous
Guest
I use both, the Simrad shows them both along with water temp etc. on the top of the display. Of coarse, I'm not bright enough to"think" in either so it's probably good they both show. :wink:
Mike
Mike
William and Beth Tucker
New member
We use mph.I have knots in my ropes and knots in my stomach.I'am too old to change...I'am glad i was potty trained when i was young..Keep your life jacket on ! tucker.]
The ICW's are marked in Statuate miles, so we use Statuate miles when on the ICW's. If we are gping in more open areas we will usually use knots, because it is sligtly easier to plot on a chart (one nautical mile equals one minute of lattitude). Take your dividers from the distance you want to go, and transfer this to the lattitude on the side of the cart to give nautical miles.
Converted from KTS to MPH for daily use.
The ICW measures the distances in statute miles, as do the local cities on their navaids for speed & distance. So, MPH is primary tools locally.
I prefer the KTS for the simplicity of my simple mind from the tears & years of flying as ASW aircrew and working/servicing flight simulators.
The ICW measures the distances in statute miles, as do the local cities on their navaids for speed & distance. So, MPH is primary tools locally.
I prefer the KTS for the simplicity of my simple mind from the tears & years of flying as ASW aircrew and working/servicing flight simulators.
Hi,
Warren, using 110% as a conversion is easy to do in your head, that's true. Your statement was backwards, though. It's 110% of Knots that gives you approximate MPH. (The real number is almost exactly 115%).
100 Knots would be 115 MPH, but for most speeds, like 12 knots, for instance, it's easier to mentally calculate 1.2 as 10% of 12 and then add them to get 13.2 MPH. The true result is 13.8, by the way.
I've been doing mostly ocean sailing for the past couple years, so I just use knots. I suppose when I start trailering the C-Dory to lakes and rivers, I might use MPH there. I guess it depends on whichever charts or maps or guidebooks I might be using.
By the way, does everyone know (probably not) that you can go to the Google search window and type in something like
100 knots in mph
and it will respond with the answer 115.078
You can also type in 27.32 dollars in pounds and get 12.59 British Pounds
(that one will vary with the exchange rate....)
Or 12 fathoms in feet and get 72 feet.
And on and on and on. It's an excellent unit converter and calculator and will do a lot more than I'm showing here.
Jeff Lastofka
Warren, using 110% as a conversion is easy to do in your head, that's true. Your statement was backwards, though. It's 110% of Knots that gives you approximate MPH. (The real number is almost exactly 115%).
100 Knots would be 115 MPH, but for most speeds, like 12 knots, for instance, it's easier to mentally calculate 1.2 as 10% of 12 and then add them to get 13.2 MPH. The true result is 13.8, by the way.
I've been doing mostly ocean sailing for the past couple years, so I just use knots. I suppose when I start trailering the C-Dory to lakes and rivers, I might use MPH there. I guess it depends on whichever charts or maps or guidebooks I might be using.
By the way, does everyone know (probably not) that you can go to the Google search window and type in something like
100 knots in mph
and it will respond with the answer 115.078
You can also type in 27.32 dollars in pounds and get 12.59 British Pounds
(that one will vary with the exchange rate....)
Or 12 fathoms in feet and get 72 feet.
And on and on and on. It's an excellent unit converter and calculator and will do a lot more than I'm showing here.
Jeff Lastofka
Jeff, thanks for catching my bass ackwards math.
I hope I never run aground because I mistook a foot depth for a fathom depth. Probably not much of an issue with C-Dories and with electronic depthsounders always reading out in feet, but it's still in the back of my mind.
Where would one encounter mission-critical measurements in knots?
Warren
I hope I never run aground because I mistook a foot depth for a fathom depth. Probably not much of an issue with C-Dories and with electronic depthsounders always reading out in feet, but it's still in the back of my mind.
Where would one encounter mission-critical measurements in knots?
Warren
El and Bill
New member
We have used knots, since our "knotty" (thanks, Dave S.) days of childhood and never been a problem. No wake speed signs are sometimes knots, sometimes mph -- no sweatski -- at those low speeds a few decimal points has never been critical for us. Come to think of it, those decimal points seem most critical when attached to $$.
I use knots because knots and nautical miles are the appropriate units to use aboard a boat (or in an airplane, for the same reasons). It's one unit that trumps both metric and so-called "Imperial" units.
Why? Because all navigation is done in nautical miles, and all wind velocities are reported in nautical miles per hour. Why is this? Because one minute of latitude (at sea level, average at the equator) is exactly one nautical mile, so one degree of latitude is 60 nautical miles. Every chart has a scale built along both sides...the latitude markers! Don't try to use the longitude lines the same way, it won't work.
Also, just curious, why do you need to convert? If you're working with nautical miles, you're working with nautical miles. I never convert, because...why bother? I don't understand why I need to know how many kilometers or statute miles are involved? It's navigation.
On to the next question: magnetic or true?
Why? Because all navigation is done in nautical miles, and all wind velocities are reported in nautical miles per hour. Why is this? Because one minute of latitude (at sea level, average at the equator) is exactly one nautical mile, so one degree of latitude is 60 nautical miles. Every chart has a scale built along both sides...the latitude markers! Don't try to use the longitude lines the same way, it won't work.
Also, just curious, why do you need to convert? If you're working with nautical miles, you're working with nautical miles. I never convert, because...why bother? I don't understand why I need to know how many kilometers or statute miles are involved? It's navigation.
On to the next question: magnetic or true?
The use of statuate miles on the nations rivers and inter coastal waterways is a safety issue. The tugs and commercial vessels give their position as per statuate miles, as the markers are all in statuate miles, for their security messages. For example "Securitie, East bound Tug Dora Jean, with three barges at mile 275, all concerned traffic respond on channel 13". If you were attempting to navigate in nautical miles the difference could be significant in a restricted passage. You really don't want to meet a tug pushing three barges and have to back down a mile or two (not as hard in a C Dory as some other vessels). I switched to two radios a number of years ago, when I missed a security message. I had given my message on both 13 and 16, but the tug was giving theirs on the opposite channels. I had to back a 62 foot motorsailer about 500 yards, to find a wide enough place, where I put the side of the boat against a bank, and the tug and barges sneaked by. Even since I have run two separate radios on 16 and 13 on the ICW.
Yes, Highway and statute miles are the same. I am not certain why inland waters, ICW and great lakes use statute miles, but my guess is that it relates to early canal and river navigation, where there were tow paths, and distances were measured on the path/canal.
We use the statute miles on inland waters to avoid the confusion which might come from measuring our position in nautical miles from the most recent marker. In limited visabilty, (night, fog, or even around a bend) it could make a difference as to where you would meet the tug and tow.
We use the statute miles on inland waters to avoid the confusion which might come from measuring our position in nautical miles from the most recent marker. In limited visabilty, (night, fog, or even around a bend) it could make a difference as to where you would meet the tug and tow.
I should clarify: I'm only advocating that navigators use the standard units. It's a matter of clear communication and safety, so always use the standard units FOR THE REGION IN WHICH YOU OPERATE.
If you're navigating inland waters where statute miles are the standard, use that standard. If you're operating in the ocean or marine water where nautical miles are the standard, use that standard.
I'm accustomed to marine water where nautical miles are the standard, so I'm biased in that direction. I admit I have kind of a "provincial" attitude (insofar as using a global aviation/maritime standard can be said to be provincial). It's just what we use around here, and essentially, I'm just lazy, see? That's one of my "core competencies".
If you're navigating inland waters where statute miles are the standard, use that standard. If you're operating in the ocean or marine water where nautical miles are the standard, use that standard.
I'm accustomed to marine water where nautical miles are the standard, so I'm biased in that direction. I admit I have kind of a "provincial" attitude (insofar as using a global aviation/maritime standard can be said to be provincial). It's just what we use around here, and essentially, I'm just lazy, see? That's one of my "core competencies".