On Fri, 04 Jul 2008 10:12:05 -0400, HK wrote:

Short Wave Sportfishing wrote:
On Fri, 04 Jul 2008 08:25:15 -0400, Gene Kearns
wrote:

On Fri, 4 Jul 2008 06:29:26 -0400, Jim penned the following well
considered thoughts to the readers of rec.boats:

"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.
Au contraire, mon ami!

The Yamaha fuel management gages must receive a fuel flow and GPS (or
speedometer... IMHO,useless) input. You must provide the GPS. I'm not
sure what format(s) of in/output are acceptable, but I suspect it is
configurable to standard formats IOW.... I don't think any special
interface is necessary (since you are likely using the Command Link
interface, already), if the GPS unit outputs a format recognizable to
the FMM..

http://www.yamaha-motor.com/outboard...nk/page05.aspx

No, I think Jim is right.

The link doesn't really give you any information on what data sets are
actually being shared and what format - I would assume NEMA 183.X
which is the defacto standard. The major issue would be connectors on
that harness they supply and how compatiable it is with other units.
However, being NEMA 183 systems, the connector to the hub has to be
something standard - maybe like a N connector or RCA jack.

To the point though, what purpose would having a fuel flow meter do a
calculation based on GPS? The calculation would be simpler and more
efficient to take the fuel flow data in GPH and base the rest of the
calculation on that - position has nothing to do with fuel usage. GPH
has a direct correlation to RPM and MPG - why complicate things?

For instance, if the metering system does the calculations and you
select MPG, then you know if you are using more or less fuel to reach
your destination - X miles equals Y fuel (or the inverse - Y fuel
equals X miles). Same with GPH - X miles equals Y operating time
equals Z available miles.

GPS has nothing to do with fuel usage.

Well, this has been a fun read so far.

There are *two* different Yamaha gauges available that display fuel usage.

One is a fuel management meter unit. The other is a speed and fuel meter
unit. Interestingly, the "speed sensor" on the engine is incredibly
accurate, at least it is on my boat. It gives just about the same
reading as the GPS at all times that I have noticed.

The fuel management meter shows flow, fuel available, total consumption,
and miles or nautical miles per gallon. Metric read-outs are also
available.

The speed and fuel meter unit does not display the amount of fuel
available. But it does have functions not available on the fuel
management meter.

That's similar to the unit I have with the ETEC.

I have the Command Link Multifunction Meter Installation Manual somewhere.

I'd be curious what the data format is and what version.

Still doens't answer the question though - why bother with hooking a
GPS into the system?

Short Wave Sportfishing wrote:
On Fri, 04 Jul 2008 10:12:05 -0400, HK wrote:

Short Wave Sportfishing wrote:
On Fri, 04 Jul 2008 08:25:15 -0400, Gene Kearns
wrote:

On Fri, 4 Jul 2008 06:29:26 -0400, Jim penned the following well
considered thoughts to the readers of rec.boats:

"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.
Au contraire, mon ami!

The Yamaha fuel management gages must receive a fuel flow and GPS (or
speedometer... IMHO,useless) input. You must provide the GPS. I'm not
sure what format(s) of in/output are acceptable, but I suspect it is
configurable to standard formats IOW.... I don't think any special
interface is necessary (since you are likely using the Command Link
interface, already), if the GPS unit outputs a format recognizable to
the FMM..

http://www.yamaha-motor.com/outboard...nk/page05.aspx
No, I think Jim is right.

The link doesn't really give you any information on what data sets are
actually being shared and what format - I would assume NEMA 183.X
which is the defacto standard. The major issue would be connectors on
that harness they supply and how compatiable it is with other units.
However, being NEMA 183 systems, the connector to the hub has to be
something standard - maybe like a N connector or RCA jack.

To the point though, what purpose would having a fuel flow meter do a
calculation based on GPS? The calculation would be simpler and more
efficient to take the fuel flow data in GPH and base the rest of the
calculation on that - position has nothing to do with fuel usage. GPH
has a direct correlation to RPM and MPG - why complicate things?

For instance, if the metering system does the calculations and you
select MPG, then you know if you are using more or less fuel to reach
your destination - X miles equals Y fuel (or the inverse - Y fuel
equals X miles). Same with GPH - X miles equals Y operating time
equals Z available miles.

GPS has nothing to do with fuel usage.

Well, this has been a fun read so far.

There are *two* different Yamaha gauges available that display fuel usage.

One is a fuel management meter unit. The other is a speed and fuel meter
unit. Interestingly, the "speed sensor" on the engine is incredibly
accurate, at least it is on my boat. It gives just about the same
reading as the GPS at all times that I have noticed.

The fuel management meter shows flow, fuel available, total consumption,
and miles or nautical miles per gallon. Metric read-outs are also
available.

The speed and fuel meter unit does not display the amount of fuel
available. But it does have functions not available on the fuel
management meter.

That's similar to the unit I have with the ETEC.

I have the Command Link Multifunction Meter Installation Manual somewhere.

I'd be curious what the data format is and what version.

Still doens't answer the question though - why bother with hooking a
GPS into the system?


I have no idea why you would want to do that...I do have the "depth"
readout of my Ray depth finder hooked into the GPS, and I have the GPS
set up to show that number -LARGE- on one corner of the GPS display.

I don't give a damn about mpg's on my boat. I pay attention to gph's!
Actually, I don't pay much attention to any of the instruments...other
than the tach and the depth readout. The Bay is a very visual boating
venue, and I am familiar with both shores, so I can always tell just
about where I am. On a reasonably clear day, both shores are visible.

"Short Wave Sportfishing" wrote in message
...
On Fri, 04 Jul 2008 10:12:05 -0400, HK wrote:

Short Wave Sportfishing wrote:
On Fri, 04 Jul 2008 08:25:15 -0400, Gene Kearns
wrote:

On Fri, 4 Jul 2008 06:29:26 -0400, Jim penned the following well
considered thoughts to the readers of rec.boats:

"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.
Au contraire, mon ami!

The Yamaha fuel management gages must receive a fuel flow and GPS (or
speedometer... IMHO,useless) input. You must provide the GPS. I'm not
sure what format(s) of in/output are acceptable, but I suspect it is
configurable to standard formats IOW.... I don't think any special
interface is necessary (since you are likely using the Command Link
interface, already), if the GPS unit outputs a format recognizable to
the FMM..

http://www.yamaha-motor.com/outboard...nk/page05.aspx

No, I think Jim is right.

The link doesn't really give you any information on what data sets are
actually being shared and what format - I would assume NEMA 183.X
which is the defacto standard. The major issue would be connectors on
that harness they supply and how compatiable it is with other units.
However, being NEMA 183 systems, the connector to the hub has to be
something standard - maybe like a N connector or RCA jack.

To the point though, what purpose would having a fuel flow meter do a
calculation based on GPS? The calculation would be simpler and more
efficient to take the fuel flow data in GPH and base the rest of the
calculation on that - position has nothing to do with fuel usage. GPH
has a direct correlation to RPM and MPG - why complicate things?

For instance, if the metering system does the calculations and you
select MPG, then you know if you are using more or less fuel to reach
your destination - X miles equals Y fuel (or the inverse - Y fuel
equals X miles). Same with GPH - X miles equals Y operating time
equals Z available miles.

GPS has nothing to do with fuel usage.

Well, this has been a fun read so far.

There are *two* different Yamaha gauges available that display fuel usage.

One is a fuel management meter unit. The other is a speed and fuel meter
unit. Interestingly, the "speed sensor" on the engine is incredibly
accurate, at least it is on my boat. It gives just about the same
reading as the GPS at all times that I have noticed.

The fuel management meter shows flow, fuel available, total consumption,
and miles or nautical miles per gallon. Metric read-outs are also
available.

The speed and fuel meter unit does not display the amount of fuel
available. But it does have functions not available on the fuel
management meter.

That's similar to the unit I have with the ETEC.

I have the Command Link Multifunction Meter Installation Manual somewhere.

I'd be curious what the data format is and what version.

Still doens't answer the question though - why bother with hooking a
GPS into the system?

Speed over ground and speed in water will average out to about the same in a
day of running. Sometimes with the current and others against the current.
And how many people in lakes and ocean are running against large currents
for a long time?

On Fri, 04 Jul 2008 13:49:02 GMT, Short Wave Sportfishing
wrote:

GPS has nothing to do with fuel usage.

No, it's just a tool used for management of fuel use.

Casady

On Fri, 04 Jul 2008 18:34:18 GMT, (Richard
Casady) wrote:

On Fri, 04 Jul 2008 13:49:02 GMT, Short Wave Sportfishing
wrote:

GPS has nothing to do with fuel usage.

No, it's just a tool used for management of fuel use.

I've given up trying to understand why. :)

On Fri, 04 Jul 2008 19:16:46 GMT, Short Wave Sportfishing
wrote:

On Fri, 04 Jul 2008 18:34:18 GMT, (Richard
Casady) wrote:

On Fri, 04 Jul 2008 13:49:02 GMT, Short Wave Sportfishing
wrote:

GPS has nothing to do with fuel usage.

No, it's just a tool used for management of fuel use.

I've given up trying to understand why. :)

Here's what I'm thinking.
You're traveling from A to B at what rpm and pitot speedo say is 20
knots.
The current is going from B to A, at five knots.
You don't have GPS, and are on a compass heading to Grand Cayman.
You didn't know about that current.
The engines start coughing as the fuel runs out.
It's hot as Hades, with not a cloud in sight.
For the first time you notice fins cutting through the water.
You look at the sky again. Damn, what are those vultures doing flying
so far from land?
You try to raise Wayne on the VHF, so he can get a fix on you with his
radar.
No luck. Wayne is taking photos of salt water pigs.
What do you do?
What do you do?
Oh, there's no conductor aboard to ask.
HTH

--Vic

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.

"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.

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.

On Fri, 04 Jul 2008 15:26:45 -0400, Gene Kearns
wrote:

Wouldn't it be nice to be able to figure out the most efficient RPM
for covering a given distance? Say, I want to head 30 miles offshore
and use the least amount of that $4.759 liquid gold?

My boat specs, per the Grady site:

2000 RPM 8.5 MPH 3.8 GPH 2.22 MPG
3500 RPM 20.3 MPH 10.9 GPH 1.87 MPG
4000 RPM 27.5 MPH 12.8 GPH 2.16 MPG
4300 RPM 30.7 MPH 14.5 GPH 2.12 MPG
4500 RPM 33.1 MPH 15.7 GPH 2.12 MPG
5000 RPM 37.5 MPH 19.2 GPH 1.96 MPG

Well, I think we've entered tomato/TOMAHTOE stage. :)

I understand your points - they just don't make any sense to me.

Then again, I'm not exactly normal.

Check out that helicopter POH.... same thing there, too.....

Speaking of which, I solo next week and get my "official" license.

WHOO HOO!!!