Underfloor tanks, no fuel gauge

[Kevaclone]

don't know why anyone would build a boat with welded self draining floor and under floor tank and NOT fit a fuel gauge sender or access to the top of the tank to fit one


SO now I have to get one fitted(although I am also having a flow meter fitted) so that I have an idea of how much fuel I have in the boat at any time


there is an access hole in the floor where the fuel filler hose connects to the front of the tank but the top of the tank is still not really accessible at this point


Been told by Profish that they fitted 150L tanks to my model boat


So what are my choices here
I'm thinking the best place for a fuel sender would be the centre of the tank(or slightly rearwards of it) as it will show far less variation in fuel level with movement than anywhere else.


looks like I'll have to have another hole cut in the floor to have it fitted


open to suggestions

[djfish71]

Best place for a fuel sender is in th rubbish bin stick with the flow meter

[D river]

Yeah mate they never read properly stick with the flow meter n be sure to calibrate it. I know my boat that well now days i can tell within 5L how much I have left just by the kms travelled.

[The-easyrider]

Yeh go the flow meter best thing I have fitted to my boat dont even look at the gage now as when it shows empty I still have 100 litres left

[Spaniard_King]

seeing this more often these days... most just fit a fuel flow meter with the abillity to enter fuel tank data to the display unit

[snatchy]

Just in case you are not convinced.
For me it is very cut and dried; I vote for the fuel flow meter
fuel guage = complete waste of time looking at it, let alone going to all the trouble of installing one.

[Kevaclone]

I was sold on the idea of a fuel flow meter from the start
just would have liked a gauge also

[White Pointer]

G'day,

Boat builders are a pretty conservative lot and know some simple rules.

1. If your boat is sitting level to the ground on a trailer the fuel gauge is probably accurate.

2. If your boat is in the water the weight of engine(s) and the natural balance along the keel might make you think you're low on fuel.

3. Depending on how you trim your boat, you can get any result you want.

Fuel guages in boats don't actually work very well. So many boat builders don't bother introducing and electrical current into your fuel tank. It's a waste of time, could be misleading and could become dangerous.

I don't have a fuel guage. I have a very nice notched stick that tells what I need to know.

Regards and happy 2011 to all of you.

White Pointer

[Kevaclone]

stick method was all I needed in the V-Sea and the tinny before it
been using "The Stick Method" for more than 20 years in my job(most important to avoid major environmental problems)

[Danf]

On my boat, I always carried a strip of aluminium painted black with calibrated notches at set intervals. You can use this method if you can reach the bottom of the tank from the filler. I also fitted VDO gauges on other vessels, the ones that use a sender located in the tank. Fitting this to a tank which is full a fuel vapour is a little daunting when using a hole saw to cut the aluminium. It will be more difficult if the tank is stainless steel. Then this has to be sealed properly because the last thing you would want is a leaking joint. This type of gauge may not always be easy to calibrate as it may not be exactly matched to the tank depth. Fuel flow meters were not readily available back then, but with the advancements in technology I would tend to go with one of these nowadays.

[ozscott]

I have had the Navman fuel flow with dedicated head unit for about 8 I guess years on 2 boats and it has always performed very very accurately when set up right. I wouldnt bother with a tank dip these days. Keeping that lid closed just has to be a good thing.

Cheer

[trueblue]

notched stick fuel gauge.

I have also just recently bought a fuel flow meter.

[Kevaclone]

Next question
where to get one from. Google is a bit vague as to retailers of them

[Kevaclone]

I have had the Navman fuel flow with dedicated head unit for about 8 I guess years on 2 boats and it has always performed very very accurately when set up right. I wouldnt bother with a tank dip these days. Keeping that lid closed just has to be a good thing.

Cheer


Been speaking to some people and they all tell me the Navman WAS a great bit of gear

Unfortunately when they were taken over and then incorporated and merged and mashed into other companies they stopped making them


might have a lead on a custom made setup, hopefully that happens soon

[ozscott]

Something I should have mentioned mate. From memory the instructions said that the laser transducer in the Navman didnt work well with EFI motors - on the basis that they didnt flow like the same as a carby motor. Dont know if thats true but it might be of assistance. From memory there was a US company that was doing a similar unit.

Cheers

[Coontakinta]

Something I should have mentioned mate. From memory the instructions said that the laser transducer in the Navman didnt work well with EFI motors - on the basis that they didnt flow like the same as a carby motor. Dont know if thats true but it might be of assistance. From memory there was a US company that was doing a similar unit.

Cheers


Laser transducer????:-?
Am I missing something here.
Have had the NAVMAN fuel management sytem since day dot on my boat. Over 5 years. The transducer has a small / light fan or wheel. What ever you want to call it.

Motor is a TLDI 90, no issues with the unit or its integrity after having a faulty unit installed on the boat replaced. Same system operates on my mates 130 Honda & again no issues.

Kevaclone, be intersted to hear of your experiences with after market stuff as have another buddy running a 115 Merc 4 stroke looking at this bit of kit for all the reasons explained to you above as to why a fuel gauge is a waste of time.

Ozscott, no malice intended.:) Sorry if it reads that way :-[

[oldboot]

What facinates me is that a floor is welded in and no provision for cleaning or inspection has been provided.....the fuel guage issue aside.

cheers

[wetryin]

Dont know if this helps but it works for me.
Worst case scenario if I am at full throttle I get 2km out of a litre of fuel. I have a 110 lt tank so I can go 220km on a full tank if I go flat out.
When I fill up I zero the distance travelled on the gauges and make sure I dont go over the 200km range.
I also have the fuel management systems on the lowrance sounder but never used it.

[Mindi]

See my post below on gauge problem....i have a navman flow meter butvafter a fulty one replaced am still trying to calibrate it...agree general sentiment of flow meter way to go.having spent money on replacing gauge system unsuccessfully i might cut a hole for a dipstick as my flow meter backup...they dont lie or fail

[Mindi]

This post has given me my way forward with my fuel gauge problem. I am totally over pulling my floor out to service the sender ....and over the uncertainty of the reading...not to mentionnthe fact that i cant solve my current problem anyway.
I am going to dump the sender, put the dead gauge back in the dash, fit a plastic inspection hatch in the floor over the tank centre, fit a fuel filler cap into the centre of hte tank under the 8" port.....then calibrate a dowel dipstick. They dont lie, and theyndont fail, and if you take the trouble to calibrate it it is plenty accurate enough. Thanks to those above who reminded me of that .....if simple works ..do that.
Then when i calibrate my navman paddle wheel transducer better i will have two systems

[tunaticer]

I have a mechanical float fuel guage that is mounted in the top of the tank.
The guage reads the float level by travelling up a 90 degree twisted metal bar that mechanically turns the pointer in the guage. Simple, clear anf accurate, plus it is straight down between my feet to look at.

Who sells these fuel meters?? The son in law wants to investigate this.

[Kevaclone]

Lowrance also make one, Bias Boating sells it and it is in their cattledog
They sell the bits separately(to maximize profit no doubt) and not as a complete kit
The dash unit(two sizes), the flow meter and a wiring harness(why that is separate I don't know), about $480 all up


Otherwise you are looking at the commercial stuff at $1000 or more