fuel tank gauges

[anchorout]

I just idled for several miles to a fuel dock, trying to stretch, what I thought was an empty fuel tank. Imagine my amazement when the 20 gallon tank only took 10 gallons fuel.

Let me say that I have been duped before by these tanks. I have tried the "use a big flashlight" method, which works great...on a dark and moonless night. Then I cut the familiar oval ports into the dress up boards which hide the tanks. I now have a great view of the sides of these grey tanks. The tanks aren't clear, as in other model years.

These tanks have no ports on top to add manual gauges or sending units. My question is, is it possible to add gauges by hole-sawing a port, adding a gasket, and using screws, taped into the plastic, to hold it all together? Has anyone tried this? Is there a better method of adding a sending unit? Am I begging for a leak? Has anyone found a better way to solve this problem?

A "search" found no answers.

[rogerar]

The plastic will not hold the screws. Use a bigger flashlight, the LED's are coming out brighter all the time.
I have a 1999 w/ faded red tanks, and that's to only dependable solution.
Roger

[Casey]

As an alternative to cutting into the fuel tank(s) you might want to install a fuel monitoring system like the Navman Fuel 2100. (Oop's, I just noticed that the Navman Fuel 2100 is no longer available. But maybe through eBay or some other source.)

The device measures fuel usage directly through the fuel line and can be quite accurate. The only problem is with very low power settings where there often is insufficient fuel passage to give a good reading. ...still, it may be better than the traditional float-type fuel gauge.

There are other accessory items you can buy for Honda, Yamaha, Suzuki engines (and probably other manufacturers we well) but I think they tend to be more expensive than the Navman device.

Best,
Casey&Mary

[Will-C]

I would keep track of the hours you run the boat starting out with full tanks. Then after running the way you normally would for four or five hours; refuel and divide the total fuel added by the hours that you ran to get a rough idea of your fuel burn per hour. Then just keep track of the hours you run the boat. Boat fuel gauges generally are not to accurate for too long. Too much bouncing around I guess when tanks are less then full. Fuel monitoring systems are the most accurate. Our Garmin chart plotter displays the fuel that's left on board at the bottom of the nav screen. It's pretty well spot on but you have to remember to add fuel to the system when you fill up or add fuel to the system. Adding to fuel on board is also done through the chart plotter. Garmin still offers the GFS 10 fuel monitoring system that works with compatible Garmin chart plotters. They also show mpg you are getting at a given speed to let you know what is the best trim etc. for optimum fuel mileage. The more accurate things like this get the more they cost. The Garmin GFS 10 system uses an inline paddle wheel of sorts which requires another small filter that goes in line before the paddle wheel type senor so debris won't ruin the sensor. If your heart is set on actual fuel gauges spring for aluminum tanks that can take the sending units.
D.D.

[ssobol]

The Navman 3100 Fuel would work, if you can find one. They are not made any more. There are issues with the display unit, but these can be repaired. The Navman system will work with NMEA 0183 for GPS info. I was thinking about getting on of these, but they are hard to come by. One issue is that the display is pretty big ~4.5x4.5". Finding a place to install it can be an issue on a C-Dory.

The Lowrance system will also work and is still available. This requires a display, a FF sender, and a NMEA 2000 network. The display can either be a LMF-200 (2") or a LMF-400 (4"). If you want the unit to calculate MPG and range you also need a NMEA 2000 GPS. You will also need some NMEA 2000 networking cables, T's, and terminators. If you don't have an inline fuel filter (e.g. Raccor) it is recommended that you install one before the sensor.

Since my existing plotter is NMEA 0183, I had to add all that stuff (except the fuel filter). The cost was a around US$500 (depends on what you can find on sale and/or eBay).

If you have a NMEA 2000 compliant chartplotter you may be able to display the fuel info on that and not need the LMF display.

The LMF displays will also show other information depending on what sensors are on your network.

At low speed on modern lower Hp FI engines you will see intermittent fuel flow on the display (every few seconds). At low speeds the engine low pressure fuel pump only operates intermittently to refill a small reservoir in the engine that the high pressure pump draws from.

One thing about this type of system. It is nice to have at first. You get to see what your fuel usage is at different conditions and speeds. However, once you have used it for a little while you will get a very good notion of your boat's fuel usage in the conditions you use it (speeds and loadings). Most of the time we cruise with the same load at the same speeds. Now that I know what my boat gets 3.65 MPG in the conditions we use it at most, I can figure out my range and fuel stops without needing the fuel flow system. It would be nice if there was some sort of portable system you could borrow or rent that calculated FF, MPG, range, etc. that you use to check your setup's performance either when you felt like it or may if you made some changes (e.g. repowered). Sounds like a job for Arduino!

[island andy]

I have never trusted marine gas gauges.
If the path from fill port to tank bottom is relatively straight, nothing beats a dip stick to know, really know, how much fuel is in an opaque tank. A dowel works well if the path is very straight. I used an old windsurfer sail batten of fiberglass and quite flexible for a Lyman with a circuitous route to the fuel tank bottom.
Clearly, one also needs to mark the stick, preferably by inscribing, to more accurately measure fuel.
However, as alluded to previously, nothing beats a translucent tank +/- a very bright light.

[Sunbeam]

Another possibility (since $500 for gauge hardware has been mentioned) is to put in a set of new Moeller tanks. When I bought mine they were around $225-$250 apiece (I can't remember exactly). That got me two brand new (and translucent) 23-gallon tanks including the fitting that comes off the top of the tank to accept the fuel hose. These are the same as the current C-Dory tanks and are shaped to fit the 22. I replaced all of my fuel system components (hoses, filters, tank cleats) at the same time, but you wouldn't have to.

This way you don't need gauges as they are easy to see through. I don't need to use a light - just look at them.

Moeller has the rights to sell this particular set of part numbers (there is a port and a starboard one) so you can buy them through any Moeller dealer (or perhaps also from C-Dory directly).

Just another option.

[hardee]

Sight gauges on the tanks would be an option too, but I would think Sunbeam's choice would be the best long term fix. My tanks are opaque and even without the "window" facing forward, I have no problem seeing my fuel level.

Harvey
SleepyC

[Sunbeam]

[hardee]

[thataway]

I have used the Navman and Lowrence units--they were basically the same, and I believe the senosors could be interchanged.

Flow Scan has made fuel flow meters and totalizers for many years. They may be slightly more expensive, but tend to have less problems than the Navman/Lowrance I had a total of 3 of the Lowrance/Navman transducers fail. I have thought about putting in a Garmin, but the "keep track of the fuel used", and the flash light works well enough.

As far as a site gauge: ABYC H24: 8.2.1
Design and Construction: openings in the gas fuel tank must be at or above the topmost surface of the tank--

USCG: CFR 33: 183.518 Fuel tank openings.
Each opening into the fuel tank must be at or above the topmost surface of the tank.

So without a opening in the bottom of a gas tank, you cannot make a site gauge, nor a fuel tank drain.

Some HDPE fuel tanks are made thick enough to allow a sender unit to be installed in the top. Theoretically one could attach extra HDPE or fiberglass laminate to the top of a tank to make it thick enough to support a fuel tank gauge. I would recommend against that.

I believe that plastic gas tanks are not allowed in inspected passenger vessels. (even outboard powered, where the tank is built in.)

An issue is that the HDPE tanks can meet the Coast guard fire tests. These are described H 24 for installed tanks. Yes, "Plastic" tanks can qualify. I am not sure that all C Dory tanks have. This is why any open flame in the C Dory has to be carefully considered.

[Sea-C]

Most of the guys ideas are probably much better than mine, but in a (need-to-know) situation you can use a small bulb transfer setup similar to the priming bulb on an outboard motor with about 6 feet or so of clear 1/4 inch hose attached to it that will go down into the fill hole of the tank into the fuel. (about $15.00 on EBay) Keep the bulb well above the top of the tank and lay the middle of the hose onto the floor of the boat and you can just step lightly on it to hold it in place. Just squeeze the bulb and suck the fuel up in the hose until you have fuel up to about the top of the tank and tip the bulb so it no longer seals the hose and the fuel will seek the exact level in the tank. You just have to make sure you have the bulb well above the tank so no fuel pumps out of it into the boat. You can see the fuel entering the hose. When done , lift the pump above the fuel fill and drain the fuel in the hose back into the tank. Coil the hose and slip it over the fitting on the open end of the bulb and it's all sealed up for next time. Not the best way in the world to check fuel amount but it is cheap, works, and safe if done carefully. My Sea-C tanks have been replaced with a 60 gallon aluminum, (with gages) much better idea but heavy if I fill them full.

[gulfcoast john]

Hi Tom!
I'm very lucky in that whatever senders/gauges Triton intstalled on my TC255 Hull # 0001, they work so well that I can estimate a 5 gallon change in a 75 gallon aluminum tank (port and starboard). They are so accurate I have to take into account the fore/aft incline with an inclinometer to within 2 degrees depending on the incline at the (ethanol free) pump.
The Garmin GFS-10 fuel monitor is $150, easy to install, and works great assuming your plotter is already networked. A basic network backbone is $68 or so for most brands and any idiot can install one if I can. A N2K network is more likely to work across brands than the older 0183, but even then there no guarantees. I'm a all-Garmin guy except all 3 VHF handhelds are Std Horizen GPS/DSC.
However, I think your best and cheapest option overall is a REALLY high quality, light weight, water resistant, very heavy duty 5 million CP handheld I bought:
http://www.amazon.com/Million-Candlepower-Handheld-HL-85-Spotlight/dp/B007JYU1XQ?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o03_s00
This is not a $79 Brinkman or Coleman 5 MCP cheapo. The detachable cord (with very high quality waterproof connector) alone must weigh 1-2 lbs. There are alternate cord lengths, coil or straight, and even a permanent mount plate on their web site. I was looking at permanent mount remote-contol spotlight/floodlights but this fits the bill in that you only have it exposed to the elements when you want to (when Eileen points it high out the window, avoiding the railings and bounceback). Best quality replacement bulb is $7 and no rechargeable batteries to go bad in 3 years. Unlike any other 12v plastic spot/floodlights I've ever seen or hefted, this is something you might pass on to your heirs. No LED to date can come close.
If it doesn't light up your gas level, return it. I bet it will.
Let us know what you decide on and why.
Happy Boating!
John

[Sea-C]

OOPS!! right boat, wrong name..Meant my Lori-L. Old boat was Sea-C so I just used it for my user name. Guess I should change it to the new one.

[anchorout]

Thanks to all. Sunbeam provided tank part numbers on a previous blog, if I go that way. Mounting sending units doesn't seem an option. Recommended flow meters I can research on the net. Lots to think about.