sight glass (tubes)

[jclays]

Has anyone installed sight glass (tubes) on their diesel fuel tanks?
I don't trust my gauges 100%. Got used to sticking my tanks on my previous boat. Cant do it with this boat. Its a 1997 Mainship 350. Twin Volvos, twin 150 gallon fuel tanks

 

[Mac2]

What material are your tanks? My tanks have a ball valve at the top and bottom and clear tubing between them. Very basic for my steel tanks, but it works.

 

[TJM]

I have wanted to. The technology is straight forward. Valves on the top and bottom to protect from site tube failure. I have seen glass or plastic tubing used. My old company used to make them for Navy ships using floats with magnets and all kinds of readouts.

 

[jclays]

What material are your tanks? My tanks have a ball valve at the top and bottom and clear tubing between them. Very basic for my steel tanks, but it works.

looks like aluminum

 

[Mac2]

Look forward to the suggestions. I’ve always wanted something like TJM described. PO has painters tape next to clear tube with marks/gallons

 

[Pascall]

I have them too, both on the main diesel tank and on the day tank.

Greeting,

Pascal.

 

[slowgoesit]

Our boat had them on the rear two tanks, and I added them to the two forward saddle tanks. There were already sumps on the tanks, and valves to drain off any nasties collected in the sumps periodically. Only there have never been any nasties! I just purchased fuel and caustic chemical rated clear flexible tubing, ran them up the outside of the tanks in an areas protected from damage/risk of brushing against. Installed a ball valve at the top (already had one at the sump).

1. When taking measurements:
2. Open the bottom valve
3. Open the top valve
4. Note fuel level
5. Close both valves when not actively taking fuel quantity readings

When first "calibrated", while refueling:

1. I was below decks while my wife called out every 25 gallons (using marriage savers)
2. Stopped, waited for fuel levels to even out
3. Marked level and quantity
4. Continue filling and marking readings until tank was full
5. Switch to next tank
6. Rinse and repeat

Hint: Pick a time at the fuel dock when business is slow, as it will take longer than standard fueling!

I am a firm believer in either sight gauges, or dipping tanks. I've been led astray in the past by gauges that have either failed, or given erroneous readings.

 

[tiltrider1]

Has anyone installed sight glass (tubes) on their diesel fuel tanks?
I don't trust my gauges 100%. Got used to sticking my tanks on my previous boat. Cant do it with this boat. Its a 1997 Mainship 350. Twin Volvos, twin 150 gallon fuel tanks

I use my site tubes before every trip. Allows me to run a 200 gallon tank down to 5 gallons.

I don’t know how you would add valves to an existing tank. It’s not a Case of drilling a hole and tapping. Typically, the aluminum is 1/4 or 3/8 thick. Usually, a 1/2 block is welded to the tank and then drilled and tapped giving the valve a minimum of 1/2 inch of threads for security.