Fuel flow meter

Philiz

Philiz

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Joined
23 Aug 2008
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Location
Staffordshire Moorlands U.K.
www.shabiera.co.uk
On a recent trip I noticed what seemed to be quite a difference in fuel consumption between travelling at 8-9 Knots and 13-14 Knots. It got me wondering, it would be useful if there was a relatively inexpensive flow meter which could be put in the fuel line to give an accurate readout of fuel consumption. Does anyone know of such a device?
 
Philiz said:
On a recent trip I noticed what seemed to be quite a difference in fuel consumption between travelling at 8-9 Knots and 13-14 Knots. It got me wondering, it would be useful if there was a relatively inexpensive flow meter which could be put in the fuel line to give an accurate readout of fuel consumption. Does anyone know of such a device?
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Ahemm 1 1/2 - 2 gals/hr seezy !

Tom
 
Philiz said:
On a recent trip I noticed what seemed to be quite a difference in fuel consumption between travelling at 8-9 Knots and 13-14 Knots. It got me wondering, it would be useful if there was a relatively inexpensive flow meter which could be put in the fuel line to give an accurate readout of fuel consumption. Does anyone know of such a device?
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There are fuel meters available, no idea how much they are Phil. Expencive I would think.

Not sure about your boat, but I find my options, are to keep below 8 knots or to go to 18/20 knots, where the engines are pulling full torque and therefore more efficient.

Same with the car, that has got a meter, about 70 MPH seems best.
 
PaulGooch said:
The Garmin one is around £180 per engine but only works with petrol engines.

Navman used to do a diesel one :

http://www.reliancemarine.com/Product/115/Navman-Diesel-3200-Alone-unit-only-/View.aspx

Earlier thread is here :

http://www.ybw.com/forums/showthread.php?t=161701

More info here :

http://www.floscan.com/html/blue/index.php
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Paul,

I'm after one of these and have been frustrated in my attempts to find one.

Navman link says "This Product Is No Longer Available".

Floscan link says "Septics/Canooks only".

Very frustrating! :mad:

Got any U.K. links for these things?
 
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Philiz said:
On a recent trip I noticed what seemed to be quite a difference in fuel consumption between travelling at 8-9 Knots and 13-14 Knots. It got me wondering, it would be useful if there was a relatively inexpensive flow meter which could be put in the fuel line to give an accurate readout of fuel consumption. Does anyone know of such a device?
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Electronics are probably not the answer, as Haydn might be suggesting also.

You will struggle to find something precise and cheap, that is a rare combination!

Depending on your boat, what the hull type is and the engine configuration, you will be able to identify a couple of economical cruising speeds. All boats have them, it is usually the driver that causes excess fuel to be burnt.

Likewise most boats have a duff speed range, this will be a speed at which the engine is working hard but not really achieving much and the handling may well be noticeably hard work. If everything feels nice, the engine is growling at good RPM and the handling is good then you are probably getting fair fuel economy.
 
carlton said:
Paul,

I'm after one of these and have been frustrated in my attempts to find one.

Navman link says "This Product Is No Longer Available".

Floscan link says "Septics/Canooks only".

Very frustrating! :mad:

Got any U.K. links for these things?
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The Navman is no longer produced, but maybe someone has some old stock ? I did a Google search and these claim to have some : http://www.duncanyacht.co.uk/showcategory.asp?CategoryID=2723

There's a UK company here for Floscan :

http://www.merlinequipment.com/products/system-monitoring.asp
 
Malthouse said:
Electronics are probably not the answer, as Haydn might be suggesting also.

You will struggle to find something precise and cheap, that is a rare combination!

Depending on your boat, what the hull type is and the engine configuration, you will be able to identify a couple of economical cruising speeds. All boats have them, it is usually the driver that causes excess fuel to be burnt.

Likewise most boats have a duff speed range, this will be a speed at which the engine is working hard but not really achieving much and the handling may well be noticeably hard work. If everything feels nice, the engine is growling at good RPM and the handling is good then you are probably getting fair fuel economy.
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Well yes, that's what I'm saying. You need to be at displacement speed or planing speed. Displacement for Phil will be around 6 knots, maybe less. Dunno, have not seen his new boat yet. After that is the "hump" Where even though more power is put on, you don't go much faster. The bow just goes up. At this point the engine is just working hard, using loads of juice but not going faster. Add more power and the boat flattens out and you can now reduce power. The usual best results are 200 revs less than max.

MF dont have much of a hump, but a previous boat did and used to get stuck in it.

I use two options, full power then back to cruising, around 20 knots. Or dispacement, 8 knots or so. In between is not an option.
 
hlb said:
Well yes, that's what I'm saying. You need to be at displacement speed or planing speed. Displacement for Phil will be around 6 knots, maybe less. Dunno, have not seen his new boat yet. After that is the "hump" Where even though more power is put on, you don't go much faster. The bow just goes up. At this point the engine is just working hard, using loads of juice but not going faster. Add more power and the boat flattens out and you can now reduce power. The usual best results are 200 revs less than max.

MF dont have much of a hump, but a previous boat did and used to get stuck in it.

I use two options, full power then back to cruising, around 20 knots. Or dispacement, 8 knots or so. In between is not an option.
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I'd say that your figures for Phils boat are about right. My MF805 is similar to his Series 9 and we find 6-6.5 knots to be an average displacement SOG, much more and she doesn't sound right or go much faster for the added RPM. We can maybe squeeze 8 knots, but we'll be in a hole and doing almost double the RPM, actually only a few hundred off of cruising speed on the plane. Other than that it's flat out, then back off from 3600 RPM to 3200 RPM giving a cruise of 16 to 19 knots. 3000 RPM is only just on the plane, clearly struggling at times, 3600 RPM is WOT and 3200 to 3400 RPM seems just perfect. All pretty much how you describe.
 
PaulGooch said:
I'd say that your figures for Phils boat are about right. My MF805 is similar to his Series 9 and we find 6-6.5 knots to be an average displacement SOG, much more and she doesn't sound right or go much faster for the added RPM. We can maybe squeeze 8 knots, but we'll be in a hole and doing almost double the RPM, actually only a few hundred off of cruising speed on the plane. Other than that it's flat out, then back off from 3600 RPM to 3200 RPM giving a cruise of 16 to 19 knots. 3000 RPM is only just on the plane, clearly struggling at times, 3600 RPM is WOT and 3200 to 3400 RPM seems just perfect. All pretty much how you describe.
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I think what we are all saying is. Phils 8 knots, is not very good, but much better than his 13/14 knot option, which is bloody awfull. Strange that though completely different boats, the figures seem the same.

So Phil, it seems that you can bumble along with Little Ship at 6 knots. Or zoom along with the rest of us at 20. Suppose it depends if your a pufter or a proper man.;)
 
Cant you find some burn figures/curves for your engine from somewhere? OK, they will differ for your boat, clobber on board, sea conditions etc, but the picture will be the same. Windy produce them for their boats, and then I just have a mental note that , for example, 2500-3000 revs is pretty ok, and anything above 3500 revs is eye watering.
I'm not going to drive about just to maximise fuel efficiency.. sometimes I ll go a bit faster, sometimes a bit slower. So, yeah, I sort of care whether its 50lph, or 120 lph, but whether its 50 or 65.. bit irrelevent to the day's boating.
 
hlb said:
I think what we are all saying is. Phils 8 knots, is not very good, but much better than his 13/14 knot option, which is bloody awfull. Strange that though completely different boats, the figures seem the same.

So Phil, it seems that you can bumble along with Little Ship at 6 knots. Or zoom along with the rest of us at 20. Suppose it depends if your a pufter or a proper man.;)
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Strangely, she seemed to use more at 6 knots than at 13-14 knots. She cruises nicely at 16-17 knots, which I suspect is the most economical, but sometimes we like to just potter along slower.
Pufter eh?? I hold him Tom, you........................
 
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