Fuel Flow totalizer

[Jerry Clark H356 SV Persi]

As anybody installed a fuel flow totalizer? I would like to monitor my total consumption. My setup is diesel tank to Racor primary filter, then fuel line splits to two lines; one to Generator, one to Yanmar 3Gm30. Both engines return to the tank, so return flow would have to be added back to fuel remaining. Just wondering if an out of the box solution is available and at what cost.

 

[kloudie1]

http://www.floscan.com/html/blue/seriesdetail.php?sid=1&catid=2
These can be had in the low flow ranges that you'd need.
looks like $700+

 

[Stu Jackson]

Jerry, you could do that at pretty hefty expense to measure the supply consumption, but you're right about not knowing the return.

An alternative would be to ask what skippers' expereinces have been with 3Gm30 overall fuel consumption in GPH, and research the same for your generator.

Many of us have been measuring our own fuel consumption for years and have very, very good handles on those figures.

Good luck.

 

[Dan Johnson]

Fuel flow...

Over the years I have used the calculation factor of 1/2 gallon an hour at cruise RPM (2,700 - 2,800) for my 3GM30F and found it to be nearly accurate for SOTP estimates.

 

[Stu Jackson]

I've been keeping track of our fuel consumption, and have noted that using "cruising rpms" is meaningless, since I have found consumption is averaged over all sorts of rpms: cruising, slow idle when gunkholing, half speed. It doesn't matter, since it's an overall average that includes ALL rpms in regular use.

 

[Jerry Clark H356 SV Persi]

I've kept meticulous fuel records for 11 seasons and up until early October last year I used .65 GPH for both, .4 for the Yanmar and .25 for the Northern Lights generator. When I refueled with those numbers, I was usually within 1/2 gallon but never over 1 gallon on mid 20 gallon refuelings. I now have around 1,000 hours on the 3GM30F and just over 2,550 on the Northern Lights.

I left Kentucky Lake for Florida last October, and my dual rates have been from just over 1.0 GPH to .78. This was heavy motor cruising at my standard RPM of 2750 to 2800, yielding 6-6.2 knots. We have been just under 1500 NM to date and are heading back North to Kentucky late on March 1. I didn't have a clean bottom starting out, although it was scrubbed with a brush from the dock. When we arrived in Punta Gorda, FL, I had a diver clean the bottom and my next trip to Indian Key, fuel consumption went down to .78 for both, so part was due to a dirty bottom. We are heavily loaded due to cruising, so some if my increase can be attributed to just more drag from the increased load. I suspect we are using more generator fuel too as we have laptops, 2ipads and 2iphones, smartphone charging, a sat optimizer to use with xGate while offshore, and we run the HVAC continuously, many times during the day with the companionway doors open to the full enclosure surrounding the cockpit.

I would really like to know my consumption while actually using fuel. Kloudie who has low flow for $700? Has anyone actually installed one, and is it difficult? $700 is higher than I would like to spend, but I might do it if the install is not too complicated.

 

[Dan Johnson]

Stu...

I guess we're saying almost the same thing. Basically the half gallon an hour consumption includes all the various engine uses you described. It is an overall average but the bulk of engine run time (and therefore fuel use) is in cruising mode.

 

[Stu Jackson]

Dan...

Yup, we agree. :dance:

 

[kloudie1]

Jerry, the FloScan guys in the link on my post (#2) have the instrument and transducer. The instrument includes a totalizer. I don't know of any small boats who've installed, but I have seen a few in larger motor yachts. The problem with diesel fuel flow is that you need two very accurate flow sensors; one for the fuel from the tank, and one for the return line.. Measuring very low flows accurately is not easy.
I use 0.5 GPH myself in doing fuel consumption estimates for my 3GMF . I don't have a generator, so, like the other folks, I find the estimate OK for my use.
Looks like you couuld use their 6500/6600 meter in a 0-5 GPM scale with their low flow transducer .. If it were set on the total flow out and into the tank, it would measure and totalize both the gen and propulsion engine. Ya probably should drop those guys a call if interested.

 

[Jerry Clark H356 SV Persi]

Kloudi1: Thanks for the information. I'm going to give them a call and see what they think. It might not be very accurate since the flows are well under 1 GPH. Also thanks to everyone else for your input. I'm starting back north at the end of the month and have a 1400 nmile trip. Probably don't have time to get it and get installed before I start back, so maybe next year project if it owns out.

 

[Steve Dion]

Jerry: Have you considered a day tank (5-10 gal) for the generator. This way you could refill the day tank from the primary. That way you could monitor the hours/consumption/transfer in a log.

This would be a good reserve in an emergency and a lot cheaper than a flo monitor that may not be very accurate.

 

[Jerry Clark H356 SV Persi]

Steve: Haven't considered a day tank. Don't know where I would put one as I have a lot if stuff stored in the lazarettes. Interesting idea though, and could transfer via electric pump.