Units

[achris]

I have noticed that everybody posting speeds uses miles per hour... Surely we should be using knots in such a marine environment... Knots is the only speed measurement that actually has proper meaning.

Knot=nautical mile per hour. 1 nautical mile is one minute of latitude... So one knot is the passage of one minute of latitude in one hour.
Kilometre.. Napoleon decree that the distance from Paris to the equator be 1000 kilometres... (He got that wrong too).
Mile... what is a mile? 1760 yards, 5280 feet... Just a number... It relates to nothing in the real world....

So, how about we encourage people to use the correct nautical terms?

Any takers?

Chris.........

 

[Limited-Time]

Re: Units

Knot this one......

 

[mthieme]

Re: Units

That's what I use (knots).

Oddly, every boat speedometer I've seen measures mph including the one in my Searay.

Real world is that there are 300 million people over here that never converted to the metric system making the archaic measuring system we still use kinda important.

 

[bootle]

Re: Units

Taking a horse to the water is one thing, making it drink is another.

 

[achris]

Re: Units

That's what I use (knots).

Oddly, every boat speedometer I've seen measures mph including the one in my Searay.

Real world is that there are 300 million people over here that never converted to the metric system making the archaic measuring system we still use kinda important.

Knots and nautical miles are not metric.... They are maritime units, that predate the metric system...

 

[mthieme]

Re: Units

True.
Isn't it interesting that someone sliced up the earth laterally before longitudinally? The latter being the basis for the metric system - which is what I was thinking at the time I was typing. (sorry)
Still a minor point compared to the mph thing.

 

[CATransplant]

Re: Units

Well, in keeping with your suggestion to use an archaic marine unit to measure speed, I think we should all abandon our speedometers and use a knotted rope to determine our speed on the water. Just let me get my chip log and heave it over the side.

And, while we're at it, let's abandon the use of our GPS systems and all buy sextants and chronometers.

 

[DrCox]

Re: Units

I think its ok to use MPH if you are used to using electronic devices such as GPS. GPS gives speed over ground, so where KNOTS will give you speed through water, its not always accurate.

For example:

If I am traveling up the Columbia river at 30 knots, but the river has a current facing me at 6 knots my guage may read 36 knots, but speed over ground I am actually only gaining 24 nautical miles per hour.

So I think Speed over groud is the best no matter what application.

/my 2 cents

--DrCox

 

[Lurker Lou]

Re: Units

Well, in keeping with your suggestion to use an archaic marine unit to measure speed, I think we should all abandon our speedometers and use a knotted rope to determine our speed on the water. Just let me get my chip log and heave it over the side.

And, while we're at it, let's abandon the use of our GPS systems and all buy sextants and chronometers.

Please, don't wind zkris up.

 

[CATransplant]

Re: Units

"Make ready to heave the log!"

Measuring speed with the log requires three people. One to heave the log, another to count the knots, and the third to watch the sandglass. Use the 28 second glass for slow sailing, or the 14 second glass for fast sailing.

"On my mark, heave the log."

Good coordination among the team was needed, since accuracy depended on perfect timing.

"Mark!"

The log was heaved at the beginning of each watch.
==========================================

Aw, heck...my GPS says I'm making 14.7 MPH. That's good enough for me. Besides, I can't really carry three people on my 12' tinny, anyhow.

Seriously, there's a fine chapter in Moby **** about using the log. I don't remember all the details, but they're in there. How far we've come, eh?

 

[DJ]

Re: Units

"Make ready to heave the log!"

Measuring speed with the log requires three people. One to heave the log, another to count the knots, and the third to watch the sandglass. Use the 28 second glass for slow sailing, or the 14 second glass for fast sailing.

"On my mark, heave the log."

Good coordination among the team was needed, since accuracy depended on perfect timing.

"Mark!"

The log was heaved at the beginning of each watch.
==========================================

That would be really interestring at 80 MPH, er ???? knots.

 

[SpinnerBait_Nut]

Re: Units

Sorry, I am old school, MPH works for me.

 

[mthieme]

Re: Units

Well, in keeping with your suggestion to use an archaic marine unit to measure speed, I think we should all abandon our speedometers and use a knotted rope to determine our speed on the water. Just let me get my chip log and heave it over the side.
And, while we're at it, let's abandon the use of our GPS systems and all buy sextants and chronometers.

Now you're talkin'. I'm with you.

When I was a kid, I remember using knotted rope with the weight on the bottom to take soundings.

 

[JoeCrow]

Re: Units

With most boats having a speedo that reads in mph and gps units reading in mph, how would we gauge kph?
Short of CT's keel-hauling rig, it doesn't seem very practical to not use what's already in place
Just my opinion

 

[mthieme]

Re: Units

My GPS can be set for MPH, KPH, or Knots.

 

[OldePharte]

Re: Units

So, how many knots to a mile?

Our particular lake has mile markers.

 

[mthieme]

Re: Units

As AChris pointed out, there are 5280 feet in a mile, 6000 in a nautical mile.
One nautical mile per hour works out to roughly 1.1 mph (1.13636)
So when my Searay is going 34 knots (nautical miles per hour) it works out to roughly 38 mph. I multiply x 1.1 and round up to the nearest mph.
This isn't exact, but I don't really need to know that I am actually going 38.636636636 mph, and it's probably more accurate than most speedometers.

 

[External Combustion]

Re: Units

Inland waters have historically always been measured in miles and speed in miles per hour. It made a lot more sense in the days of keel boats and steam boats. Many of the small boat manufactures pitch to the inland waters guys. Can't blame them because of the market share.


By the way I still use my sextant, chip log and lead. Electronics are faster, easier and more accurate. Yes, a single operator can do a chip log and steer at displacement speeds. I would like to see the reel size and the arms of the heaver for a chip log built for 40 MPH.

 

[OldePharte]

Re: Units

As AChris pointed out, there are 5280 feet in a mile, 6000 in a nautical mile.
One nautical mile per hour works out to roughly 1.1 mph (1.13636)
So when my Searay is going 34 knots (nautical miles per hour) it works out to roughly 38 mph. I multiply x 1.1 and round up to the nearest mph.
This isn't exact, but I don't really need to know that I am actually going 38.636636636 mph, and it's probably more accurate than most speedometers.

So there are 6,000 knots in a mile of chip log string?

 

[mthieme]

Re: Units

We need the Admiral to answer that one.
The lines I used for soundings had knots tied every 6' (fathom).