Petrol fuel flow meter?

ian38_39

ian38_39

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Given that petrol is so expensive and my boat has an insatiable thirst for the stuff while out at sea I thought about fitting a flow meter.

Has anyone got any expierience of these?

I have twin 205hp V6 Volvo 431b petrols and thought fitting just a single flow meter would basicaly half the cost, my reconning being that if both engines are running the same RPM then they should be using pretty much the same, if I know what is going on with the one engine and tank then I can work out the rest for myself.

Is this wise?

Are these things worth fitting?

Which is the best value (cheapest that works)?

Do they connect to GPS to give MPG?

Ian
 
I'm not sure what you are hoping to achieve. Fitting a flow meter will tell you how much fuel you are consuming. I guess you can therefore optimise your cruising speed to suit. But can't you do this anyway? I assume yours is a planing boat. Backing off the throttles to a couple of knots above the point she drops off the plane is most likely to give you the best cruising consumption.
 
I had twin petrol's on the last boat 2 x 4.3 V6 Mercruiser on a 29ft Sports Cruiser Year 2002 (Sold boat in April this year)

Used Northstar/navman flow meters linked to the Northstar plotter.

I was interesting to see the following:

5 kts = 2mpg (May be a little more)
8 kts = 0.8 mpg
15 kts = 1.2 mpg
24 kts = 1.4 mpg
26/28 kts = 1.6 mpg
33 kts = 1.1 mpg
(These are about right as far as I can remember)

So the theory of just on the plane did not work at all.

It stopped me assuming I was being economic at certain speeds.

Wish I had them on the new boat
 
Certainly I would like to ascertain my most economical cruising speed and it could even be that a tweek here and there over what I think is best speed, trim etc., could produce sizeable savings, equally important though is knowing what is left in the tanks.

Running at 22 Knots I get between 1 and 1 1/4 to the gallon and tank capacity is 128 gallons. Petrol is difficult to find so fuel stops have to be planned and often involve a detour.

If a call is marginal then obviously you will always take the detour but if you know exactly what is left then you may well be safe to continue and cut out the detour.
On a passage plan I am working up now that could save me 48 miles, of which 24 miles worth of Fuel will be out of the tanks by the time I get back on route.

Ian
 
I have a Navman set up on my single engined boat (5.7 GXi Volvo). I can confirm that once on the plane, mpg increases markedly up to a certain speed (gallons per hour increases as expected).

The Navman gear has proved to be accurate "out of the box" and very accurate once calibrated ( I've had it on my boat since 2005).

The simplest display only indicates GPH/ LPH
The next one up can be connected to a GPS and indicate MPG, range etc
The third option is to connect it to a Navman Chartplotter (which is what I have on my boat). This can actually indicate the fuel level visually and has an adjustable low level alarm function ( much more accurate than the fuel gauge!).

The actual transducer for all types is the same, but the plug at the end is different depending on whether it's for fitting to a chartplotter or a gauge. (Adaptor cables are available apparently).

One practical hint; due to the brittle potting compound they use on the transducer and that it penetrates the cable, you need to prevent the cable flexing there; or else it will break ( the cable can be cable tied to the fuel outlet hose).

The Lowrance and Floscan units also have a good reputation in the US, where, surprisingly US owners are getting more concerned with fuel economy!
 
We have one, and use it more than the speedo...

Tend to keep an eye on rev's and fuel flow (built in to guages) more than anything else, suits us... Very handy if your looking to save a few £ on fuel...
 
have seen the Lowrance LMF200 multifunction display head with a fuel flow meter and I can buy another meter as well.

Could I use the one display to combine the information from both flow meters?
 
Thanks Graham, have been reading a bit more and it appears that it requires a nmea network and wil not work as a stand alone.

My Standard Horizon Plotter is nmea and outputs the right sentances to feed the speed data to the unit to allow MPG calculations but how much is involved with the network for a Lowrance device.

Is it just a case of a wire with a couple of plugs and a live feed?

My plotter already outputs to my VHF for DFC, I already have a sea talk network connecting the Auto pilot, Radar, GPS and Speed and depth logs and I suppose I have a partial network between the VHF and Plotter but what is involved in the Lowrance network thing?

Ian
 
At first glamce, the LMF200 document that can be downloaded from their website seem to make it seem quite simple; I've never set up a NMEA 2000 network though !
 
This question perhaps applies to the people that already mentioned that they have fitted a Navman/Northstar fuel monitor to their boat (or indeed to peoplle who have any knowledge of these devices) - I would like to know if the "paddle wheel" mentioned in the marketing literature is essential to get the best out of the flow meter OR is this only necessary if speed from a GPS device isn't available?
Am I right in thinking that the Navman/Northstar meter will communicate with a GPS system - in my case it's a Garmin 550 Fishfinder and the speed from the GPS can be linked to the fuel meter in order that all of the benefits from the meter can be used? i.e. range, fuel used, fuel remaining etc.

AND (I'm sorry for going on!!)

there isn't actually any additional sender unit added to the fuel tank? The data that the meter produces is done purely on the amount of fuel YOU tell it the boat is carrying?
I hope this makes sense to someone!!
Thanks
 
Some Garmin plotters can have a fuel flow meter added they are about £160. I will add one of these later this year as my v8 had a serious petrol addiction.
 
GrahamHR said:
At first glamce, the LMF200 document that can be downloaded from their website seem to make it seem quite simple; I've never set up a NMEA 2000 network though !
Click to expand...

Lowrance have some NMEA 2000 guide documents on their website.

However NMEA 2000 and the older NMEA 0183 (that most people are familiar with) cannot be joined together without additional interface hardware. So to get MPG you obviously need a source of speed such as a log or GPS in addition to the fuel computer, Whilst you may have these already, unless they are NMEA 2000 (e.g. Some Raymarine chartplotters etc) you will need something like an Actisense interface to get the speed signal from an older NMEA 0183 unit into the Lowrance 200 display.

Not as complicated as it sounds, but something to be aware of depending on what hardware you have already.

BTW te 200 is a very nice little unit and can display all sorts of other NMEA 2000 info. Also the Lowrance fuel sensors are a lot cheaper than Garmin's, being only about £50 each

Anthony.
 
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you will need something like an Actisense interface to get the speed signal from an older NMEA 0183 unit into the Lowrance 200 display
Click to expand...

Speed is converted by the Actisense NGW-1 but there are other conversions that are currently unsupported. Some are not yet written and others are simply not possible. There is no engine data in NMEA 0183 so there can't be a conversion. I would recommend to anyone considering buying one to check the supported conversion list on our website first to make sure it is what you need.
I'm not allowed to post a link because of our commercial interests. You will find the list under products/NGW-1/downloads/conversion list.
 
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