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#31
posted to rec.boats
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Yamaha Fuel Management Gauges
"Tom The Prophet" wrote in message ... On Fri, 4 Jul 2008 15:38:21 -0400, "Jim" wrote: "Short Wave Sportfishing" wrote in message . .. On Fri, 04 Jul 2008 11:39:02 -0400, Gene Kearns wrote: GPH is pretty meaningless when one wants to determine fuel consumed per distance traveled. Miles per gallon is really what we want to know, since that is a better measure of fuel economy. (Least fuel consumed, per mile, is my goal, anyway.) Please take no offense, but that doesn't make any sense. You have to have a base calculation which would be gallons per hour (actually I've been told that the true base is per minute) because it's the only true way to measure fuel usage. Thus, you use X fuel over Y time. So what can be the variable in the equation - RPM. At low RPM, G(used)PH goes down and when RPM rises, G(used)PH goes up. Thus, at A revolutions you use X Fuel over Y time. That cannot change - it's the base calculation. Now from there, you can make whatever calculation you want - furlongs per fortnight or miles per gallon - it doesn't matter because it's all based on GPH. It can't be any other way. Feed distance, time, and gallons consumed into the computer and out comes MPG. That's fine, but it's still the same number as GPH. You have still used a certain amount of Gallons Per Hour. You asked a question in another post: Heading upstream in a 10 MPH current at 8 MPH would give what sort of MPG???? Sooner or later the fuel tank would overflow...! That's exactly the point of GPH - you have a known figure. If your not making headway, you are still using fuel - GPH again. There are simply too many variables to calculate MPH over water. You can use a GPS log of total miles traveled to calculate MPG of a particular trip. That won't necessarily compare to the same trip on a different day. You can collect data and come up with averages if you want. That might be useful. You can reliably chart GPH at given throttle positions and then convert throttle position to approximate MPH(over water, not land). You and I are on the same page but the other folks don't buy into what we are saying. No big deal. You've wrapped it up much more clearly that I did. :) It's actually a tomato/TOMAHTOE thing - I'm comfortable with GPH and others are comfortable with MPG. No worries. I need an average MPG, as if you are running to an upriver or offshore point, it would be nice to know if you have enough fuel capacity. I could slow down and get a little better mileage, or go faster for fun. |
#32
posted to rec.boats
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Yamaha Fuel Management Gauges
On Fri, 4 Jul 2008 17:11:39 -0400, "Jim" wrote:
"John H." wrote in message .. . On Fri, 4 Jul 2008 11:18:42 -0400, "Jim" wrote: "Richard Casady" wrote in message ... On Fri, 4 Jul 2008 06:29:26 -0400, "Jim" wrote: "Graham" wrote in message news:ypjbk.54744$Jx.31786@pd7urf1no... Does anyone know if these gauges display miles per gallon (or litres per km) or just miles travelled and gallons consumed? Do they need any special interface to work with standard GPS's like a Raytheon chart plotter? Thanks, Graham The GPS reports miles per hour over land. It would be useless to use those calculations in determining real miles per gallon over the surface of the water. It reports MPH everywhere equally well. It doesn't know sea from land unless you get it wet. It reports speed over the land and if the land is flooded, at sea or on a river, THIS IS THE WHOLE POINT. If you are heading against a 5 kt current at 10 kts, what speed will the GPS report? 10 knots. But, without the current, you'd be making 15 knots all else being equal. Wrongo old bonged one. The GPS sees you doing 5MPH over ground. What matters on a boat is your speed thru the water. Speed thru the water is determined by your throttle position which has a relationship to RPM and GPM. These things are predictable and repeatable. When you want to know ground speed toward destination you need to take into consideration current and drift. Same thing in an airplane. There is ground speed and air speed. They're different. Sorry you got bonged. I wonder why Harry got less jail time for a more flagrant rule violation? No. You assumed the 10 knots was the speed over water, I assumed the 10 knots was the speed over ground. No problem with the bonged bit, and since I didn't see Harry's stuff, I can't comment. Chuck and I have been having a running discussion about 'the threesome' and their behavior. Apparently he's decided that discussion and criticism of his rules is against his rules. And, that's OK. I wish he'd said so up front. |
#33
posted to rec.boats
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Yamaha Fuel Management Gauges
On Fri, 04 Jul 2008 21:12:17 GMT, Tom The Prophet
wrote: On Fri, 4 Jul 2008 16:47:55 -0400, "Jim" wrote: Don't forget to bring human fuel too. Cannibalism? EEEEWWWWWWW...... He said 'human fuel', not 'human, human fuel'. There's a subtle difference. |
#34
posted to rec.boats
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Yamaha Fuel Management Gauges
John H. wrote:
Chuck and I have been having a running discussion about 'the threesome' and their behavior. Uh-huh. I can only imagine the "discussion" Chuck has been having with you. He must be holding his nose, because, when it gets down to brass tacks, you stink. (nicely mixed metaphor, hey?) |
#35
posted to rec.boats
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Yamaha Fuel Management Gauges
On Jul 4, 5:11*pm, "Jim" wrote:
"John H." wrote in message ... On Fri, 4 Jul 2008 11:18:42 -0400, "Jim" wrote: "Richard Casady" wrote in message . .. On Fri, 4 Jul 2008 06:29:26 -0400, "Jim" wrote: "Graham" wrote in message news:ypjbk.54744$Jx.31786@pd7urf1no... Does anyone know if these gauges display miles per gallon (or litres per km) or just miles travelled and gallons consumed? Do they need any special interface to work with standard GPS's like a Raytheon chart plotter? Thanks, Graham The GPS reports miles per hour over land. It would be useless to use those calculations in determining real miles per gallon over the surface of the water. It reports MPH everywhere equally well. It doesn't know sea from land unless you get it wet. It reports speed over the land and if the land is flooded, at sea or on a river, * *THIS IS THE WHOLE POINT. If you are heading against a 5 kt current at 10 kts, what speed will the GPS report? 10 knots. But, without the current, you'd be making 15 knots all else being equal. Wrongo old bonged one. The GPS sees you doing 5MPH over ground. What matters on a boat is your speed thru the water. Speed thru the water is determined by your throttle position which has a relationship to RPM and GPM. These things are predictable and repeatable. When you want to know ground speed toward destination you need to take into consideration current and drift. Same thing in an airplane. There is ground speed and air speed. They're different. Sorry you got bonged. I wonder why Harry got less jail time for a more flagrant rule violation? http://www.tradebit.com/filedetail.p...19-Sounds-MIDI |
#36
posted to rec.boats
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Yamaha Fuel Management Gauges
On Jul 4, 9:03*pm, John H. wrote:
On Fri, 4 Jul 2008 17:11:39 -0400, "Jim" wrote: "John H." wrote in message .. . On Fri, 4 Jul 2008 11:18:42 -0400, "Jim" wrote: "Richard Casady" wrote in message ... On Fri, 4 Jul 2008 06:29:26 -0400, "Jim" wrote: "Graham" wrote in message news:ypjbk.54744$Jx.31786@pd7urf1no... Does anyone know if these gauges display miles per gallon (or litres per km) or just miles travelled and gallons consumed? Do they need any special interface to work with standard GPS's like a Raytheon chart plotter? Thanks, Graham The GPS reports miles per hour over land. It would be useless to use those calculations in determining real miles per gallon over the surface of the water. It reports MPH everywhere equally well. It doesn't know sea from land unless you get it wet. It reports speed over the land and if the land is flooded, at sea or on a river, * *THIS IS THE WHOLE POINT. If you are heading against a 5 kt current at 10 kts, what speed will the GPS report? 10 knots. But, without the current, you'd be making 15 knots all else being equal. Wrongo old bonged one. The GPS sees you doing 5MPH over ground. What matters on a boat is your speed thru the water. Speed thru the water is determined by your throttle position which has a relationship to RPM and GPM. These things are predictable and repeatable. When you want to know ground speed toward destination you need to take into consideration current and drift.. Same thing in an airplane. There is ground speed and air speed. They're different. Sorry you got bonged. I wonder why Harry got less jail time for a more flagrant rule violation? No. You assumed the 10 knots was the speed over water, I assumed the 10 knots was the speed over ground. No problem with the bonged bit, and since I didn't see Harry's stuff, I can't comment. Chuck and I have been having a running discussion about 'the threesome' and their behavior. Apparently he's decided that discussion and criticism of his rules is against his rules. And, that's OK. I wish he'd said so up front. http://www.tradebit.com/filedetail.p...19-Sounds-MIDI |
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