Fuel Computer

[ontheplane]

Hi there,

Does anyone know if there is such a thing available as a fuel computer for a boat?

I found one on e-Bay, but it was in the style of the 1950's and not quite what I want!

If you know of a GPS Plotter that would accept a fuel flow input to give a MPG reading even better (although plotter budget is a couple of hundred quid not thousands...)

No, not bought a boat yet, but some of the ones I am looking at have very large engines and finding the most economical speed will be of much benefit....

 

[Prospect and Sunray]

The navman gps plotter (mine is a 5505i) accepts a fuel flow input from a navman fuel flow meter.... the sensor is about £80. It will give you fuel consumption in mpg, range of fuel left and fuel remaining.....assuming you accurately tell it how much fuel you start with. This is all for a petrol engine.... if you have a diesel, it will still do all the above, but you need an additional kit on the fuel return pipe to tank, even the diesel kit is not overly expensive.... about £150 iirc.

 

[colingr]

Lowrance ditto. I took mine off when I saw how much I was using at WOT

 

[PCUK]

Floscan up to 2000hp.

 

[jfm]

Loads of modern plotters will display the info. Tricky part might be collecting the data. With petrol you can get a simple floscan flow measuring transducer. With older diesel you need the floscan flow and return transducers. All as explained above. But with a modern diesel you will already have the fuel data sloshing around on the engine's electronics, most likely in j1939 format and you can buy a small black box to translate it to NMEA 2000 to display on most modern plotters. A translator is Maretron J2k1000 - get one for each engine. Or if you have volvo engines they do a proprietary NMEA2000 converter, and/or sell you a software upgrade to display the fuel data in the LCD windows in their tachos, and/or sell you an EVC display which plugs and plays

 

[rbcoomer]

Reading the threads on the various boats you have looked at, I'm guessing you are considering as a retro-fit for a <25' Sportsboat - probably petrol?

I purchased one of the NorthStar flow meters when I first started with the boat. I paid about £150, but believe the units (F210?) are discontinued and quite hard to find now? I think you can get equally accurate data by keeping a log of where you go, speeds, distance traveled and by topping off the tanks to see how much you have actually used whenever possible. I now use both.

 

[oGaryo]

I have one of these on my Navman but to be honest, you have to remember (or in my case, be bothered) to reset the amount of fuel in the tank every time you fill up... you also need to calibrate the thing every now and then e.g. if the boat's bum gets hairy, consumption isn't going to be the same as when you calibrated it with a clean bum.... my advice is save your money and put it to good use by buying more fuel and apply your focus to getting the best speed for rpm instead should you need to watch the fuel consumption

 

[ontheplane]

Yes - I think we'll end up with sub 25' petrol (if I could find a quick diesel in budget that would be the choice - but I can't).

I don't want to do the averaging thing - what I want it for is when at cruise I can fiddle with the throttle and trim to try and get the optimum mpg - which will tell me what speed to cruise at.

Of course I realise that as the bum gets dirty or wave conditions alter that figure may change, but with instant figures available I can re-set my optimum cruise....

+ gives me summat to do when on a passage rather than a blast round the bay.

 

[Scillyboy]

Garmin chartplotter linked to NMEA2000 with F/F sensor gives me any numbers I need, including fuel flow at any given configuration. Clever stuff. Total cost will depend on what sort of chartplotter you choose.

 

[ontheplane]

I had a Standard Horizon CP180 on last boat - and it was brilliant for the price.

Might go CP300 next time - does anyone know whether this one accepts a fuel flow input - and if so, does it have to be a certain one?

Thanks

 

[landlockedpirate]

Its a good idea. As mentioned above they are not that accurate (I have the Navman version) but they do allow you to see the relative 'economy' at different speeds.

 

[GrahamHR]

Its a good idea. As mentioned above they are not that accurate (I have the Navman version) but they do allow you to see the relative 'economy' at different speeds.

My boat has had a Navman 5600 with the fuel transducer fitted since 2006. I know from experience that they can be very accurate indeed; on mine the comparison of total fuel burn (fuel in from Jerrycans 20 l at a time) vs fuel indicated to have been used over a season has an accuracy in excess of 99.5%, based on a typical seasons consumption of 1,300 o 1,500 litres.. If the fuel burn data is accurate, then so is the mpg or litres per Nm etc. There is a calibration which if done accurately only needs to be done the once and there is another factor that needs to be set, it's different for carbed vs fuel injected engines (my boat is not ready for the water yet, I can't remember what that input is called !).

 

[Spi D]

Faria Fuel Manager. Standalone device.

Available from eg http://www.trickettmarineproducts.co.uk/faria.html

@ £190 +VAT. Might be on offer somewhere...

 

[GrahamHR]

That sender and gauge (apart from the bezel) look extremely similar (= identical!) to the old Navman ones. I actually still have one of the gauges, fitted in 2005 before I bought the 5600 plotter in 2006. I remember now, the electrical connectors on the senders were different, depending on whether it was being connected to a dedicated gauge or a chartplotter. Be aware that the potting compound on the sender is VERY brittle and extends due to diffusion into the cable; if you flex it at the sender, it will break and also break the conductors.

 

[Spi D]

Can't say if Navman/Faria are related. Never had any issues over the six years I had it.

It has a lower limit of measure (as all do) which made it show zero when the Suzuki 140 hp idled...

 

[Scarron]

Fuel manager

Faria Fuel Manager. Standalone device.

Available from eg http://www.trickettmarineproducts.co.uk/faria.html

@ £190 +VAT. Might be on offer somewhere...

One on special offer here!

Bought one recently for my re-engine project (single efi petrol V8) then decided to replace the standard return less Mercruiser MPi injection system with a new Holley TBi system which has a return to tank, hence the Faria won't work. Doh!

Brand new in box, black with black bezel, available at a very good discount to interested forumites, PM me.

 

[gjgm]

Yes - I think we'll end up with sub 25' petrol (if I could find a quick diesel in budget that would be the choice - but I can't).

I don't want to do the averaging thing - what I want it for is when at cruise I can fiddle with the throttle and trim to try and get the optimum mpg - which will tell me what speed to cruise at.

Why not just check the consumpton figures for your or similar boat off boattest, and save the money on the monitor for beer? It will be good enough to give you a mental picture of revs/lph. I cant see the point in having a sportsboat only to drive it at the most economical speed. You want to be driving at the most enjoyable speed for the sea conditions or occasion, and damn the fuel bill. Deciding to have a really uncomfortable trip just to save money seems to have got the idea back to front, to me.
All you need to know is 2000 revs is about 50lph, 2500 about 75lph, and 3000 revs is about 100 lph (or whatever). There doesnt seem much point to me in ruining a day just to save 12 litres of fuel...

 

[Spi D]

One on special offer here!

Bought one recently for my re-engine project (single efi petrol V8) then decided to replace the standard return less Mercruiser MPi injection system with a new Holley TBi system which has a return to tank, hence the Faria won't work. Doh!

Return pipes can be eliminated by eg. Tigerloop
http://www.oilybits.com/heating-oil...-/tigerloop-original-de-aerator/prod_131.html

Known to work in motorsailer - no knowledge of suitability with petrol

 

[shetland]

Hi there,

Does anyone know if there is such a thing available as a fuel computer for a boat?

I found one on e-Bay, but it was in the style of the 1950's and not quite what I want!

If you know of a GPS Plotter that would accept a fuel flow input to give a MPG reading even better (although plotter budget is a couple of hundred quid not thousands...)

No, not bought a boat yet, but some of the ones I am looking at have very large engines and finding the most economical speed will be of much benefit....

Google Cruz Pro they manufacture a fuel computer that learns the fuel tank size when during the set up stage also works with diesel engines

 

[ontheplane]

Why not just check the consumpton figures for your or similar boat off boattest, and save the money on the monitor for beer? It will be good enough to give you a mental picture of revs/lph. I cant see the point in having a sportsboat only to drive it at the most economical speed. You want to be driving at the most enjoyable speed for the sea conditions or occasion, and damn the fuel bill. Deciding to have a really uncomfortable trip just to save money seems to have got the idea back to front, to me.
All you need to know is 2000 revs is about 50lph, 2500 about 75lph, and 3000 revs is about 100 lph (or whatever). There doesnt seem much point to me in ruining a day just to save 12 litres of fuel...

I hear you.....

BUT it's not really for that. If we want to have a blast we'll have a blast and sod the fuel consumption.

I want something to do on a longer passage. I think it would be interesting / fun to be able to see the consumption and then play with trim / revs etc to get the most efficiency from the hull, which will also teach me more about driving it, and more about the characteristics of my boat. EG - if I want to cruise at 23kts - but I find a decent difference in economy from 23 - 21kts I'll cruise at 21.... NOW if I want to have fun then I'll open the throttle and to hell with the economy.

Also pottering up the river or channel, it's hard sometimes to judge hull speed - so I can open the throttle slowly, and at a certain point the MPG will drop rapidly as I am at hull speed, then I can back off 200rpm and presto - cheaper low-speed cruising + I will get to see the different look in the wake and the feel of the boat and know what's best for all...

That Faria is good, but there is no speed input - so whilst I have a fuel flow figure I would still need a calculator and a read from the GPS to know my MPG. If that guage would take an NMEA input then that would make it perfect.