Fuel spill avoidance

I’m tired of burping diesel out the vent and into the water. My new tanks cannot be monitored for ‘nearly’ full, since the new fill hose is neither straight nor dip-stick-able. Of course, spilling diesel is undesirable, illegal, and potentially expensive.

What to do? What do current boats have? What have y’all done?

I’m thinking of installing Racor LG100 fuel/air separators. BoatUS recommends them.

I just fold up an oil diaper and tape it under the vent with masking tape. I’ve never given it an extreme test as I can hear the tube filling pretty well, but it seems to work OK.

Could use a whistle vent in association with an inline 1/2 gallon collection container on the vent line.
To be honest, I have not seen whistle vents in many years. Google does list them.

Davis doesn't make these anymore but they attach over your fuel vent with suction cups and contain any spills.

I have one and it catches any fuel coming out of the vent.

Look for one at marine swap meets, marine stores for remaining stock or eBay.

Might be able to cobble one together out of a plastic bottle.

I usually have a decent idea of how much fuel my tanks will take. Auto shutoff on the pumps rarely works, as the fill hoses are too big, I think. So I usually slow down when they're almost full and hold an oil pad under the vents to catch the little bit of overflow if I don't hear it in time to stop.

I installed the Racors for both my tanks. Very pleased with them. I no longer have to lay on the deck while pumping to hold a diaper under the vent. My body no longer bends as well as it used to and that position would get very uncomfortable. Plus the hose at the fuel dock no longer has the latch to keep the nozzle open so it was kind of like playing Twister. The Racors ended all that.

I make a point of estimating the fuel needed. When the meter gets within 20% I listen HARD to the vent. Goes for each tank.
I can hear the air coming from the vent so I listen hard.

As soon as the FIRST gurgle is heard I shut the hose off.

If ambient noise is a problem I literally lean over the vent so I can hear.
If noise is bad enough from a noisy boat docking nearby I quit fueling untill the noisy one shuts down.

I will also hold a pad below, not covering, just in case and I found it actually helps reflect the gurgle up to me.

Has worked so far although I realize lots of boats won't allow my method to work.

I also don't talk to people when fueling or there will be trouble. The only exception is my wife calling out the fuel quantity as we approach my calculations.

The Racor vent line separators look interesting. I'll have to investigate those, as they work on gas as well apparently.

As wwestman pointed out, the pad under the vent isn't practical on some boats. I'm lucky that my vents are on the transom and the fills are on the outer corners of the aft deck, so I typically fill the tanks standing on the swim platform.

There is an interesting video on youtube about a super yacht taking on fuel. They have a checkoff list of steps to be taken.

Of course many do not apply to smaller boats like ours but some are good ideas. Like plugging your scuppers with oilzorb blankets, covering vents with blankets, surrounding the fill nozzle with blankets. All good ideas.

They have a policy which I thought was kind of neat. They always took a sample of about a liter of fuel from the delivery truck and held it for future needs or analysis should the need arrise.

pete

So most spills from the vent are due to poor manufacture design. They mount the tank vent "below" the deck fill. It would seem most manufactures are changing this and mounting the vent "above" the deck fill. I have issues when filling my main tanks because of the above. However, I have two 50 gallon tanks in the cockpit. The vents are mounted well above the fill neck, no spills.

An easy way to keep from spilling is to:

1. Always monitor the deck fill and "listen."
2. When you hear a change of sound in the deck fill SLOW DOWN!
3. When you hear a "rising gurgle" from the deck fill STOP!

Will you get your tanks 100% full, no but you will have less fuel spills.

Take your time and LISTEN.

The vents for my two tanks were barely above the top of the tanks and I was always getting fuel burping out of them. I moved them up about 14 inches. The vent hoses came out of the top of the tanks and then made a bend down to lay on top of the tanks. This gave a place for fuel to sit in the low spot and I was still getting fuel out the vents. With a boat hook I was able to maneuver a piece of 2X4 under the hose so there was no more low spot. No more fuel out the vents.

C lectric said:

I make a point of estimating the fuel needed. When the meter gets within 20% I listen HARD to the vent. Goes for each tank.
I can hear the air coming from the vent so I listen hard.

As soon as the FIRST gurgle is heard I shut the hose off.

If ambient noise is a problem I literally lean over the vent so I can hear.
If noise is bad enough from a noisy boat docking nearby I quit fueling untill the noisy one shuts down.

I will also hold a pad below, not covering, just in case and I found it actually helps reflect the gurgle up to me.

Has worked so far although I realize lots of boats won't allow my method to work.

I also don't talk to people when fueling or there will be trouble. The only exception is my wife calling out the fuel quantity as we approach my calculations.

Click to expand...

This ^
My tanks are about 5 gallons per inch of level per tank. I take a level reading after tying up to the fuel dock. So if I'm at 18" and FULL is 31", then I plan to add 10" or 50 gallons per side. Never try to fill full to the top. The whole time I'm hanging my head over the vent listening for that gurgle just to be sure. My wife will be reading the fuel pump meter out loud so I can hear.

Is there any reason the tanks have to be completely full?

Fueling on our boat (GB 32) is a two-person job. The admiral runs the fuel hose while I sit in the engine room watching the sight glass. At about 90 or 95%, I yell at her to stop fueling. I have no problem with not filling the tank to the very top. Never had any problems with condensation or unusual growth in the tank because the tanks are not completely full, though I usually toss in some biocide for good luck.
Oldersalt

Accurate fuel gauges help a lot. Barring that, it you listen closely, you will hear the level nearing, and on most boats, you will hear a little burp when the level reaches the base of the vent. Same thing with water tanks.

I can tell by the sound when the tanks reach "full." Always closely attend refueling and have oil/fuel absorbent cloth at hand.

caltexflanc said:

Accurate fuel gauges help a lot. Barring that, it you listen closely, you will hear the level nearing, and on most boats, you will hear a little burp when the level reaches the base of the vent. Same thing with water tanks.

Click to expand...

And sight glass on each tank is even better.

OldDan1943 said:

And sight glass on each tank is even better.

Click to expand...

Good for estimating fuel need but not for monitoring fueling unless there is someone to monitor sight glass and another immediately near the site of fueling.

If you have Flow Scan on board and taken the time to tune the system simply pumping the amount burned from each tank works fine.

Cheaper plan Plan B is to relocate the tank air vent line higher than the tank filing deck fitting.

Up inside a stanchion is fine.

Stop filling before the fuel pours out of the deck fill.

OldDan1943 said:

And sight glass on each tank is even better.

Click to expand...

Although the sight glass gives a more accurate reading, the last inch or 2 above the upper sight glass valve is an unknown, even if you have a the tank sight glass calibrated. May I suggest, you observe the level in the sight glass before you start filling.... ask the dock master the output of the pump to time your progress (which he wont know) tape the absorption pad under the vent, hang your head over the side near the vent, listen for the gurgling. OR fill some, shut off the nozzle, go check the sight glass and resuming the fill as necessary. Yes, I do have an electronic tank indicating system but, a visual if far more accurate, IMO

syjos said:

Davis doesn't make these anymore but they attach over your fuel vent with suction cups and contain any spills.

I have one and it catches any fuel coming out of the vent.

Look for one at marine swap meets, marine stores for remaining stock or eBay.

Might be able to cobble one together out of a plastic bottle.

Click to expand...

When I had my Nordhavn, I had 2 of those plastic bottles. They fit fine and did the job. When I switched to my AT, the hull shape would not permit the proper fit so, I donated them to Chapman's School. They were very appreciative.
I also purchased and donated an airplane instrument hood. The school likes to teach the students to believe in their compass and the electronic chart plotter.
Of course, there would also be a spotter to tell the helmsman correction, when in the confined quarters of a single lane bridge and the cribbing..
A word of advice, after you have the compass calibrated.... if you still do not believe your compass, throw the compass over the side. You doubt it once and you will never believe it when desperately need.
I was the lead person when establishing a compass line for cut blocks for the US Forest Service (summer) and also for a Canadian logging company (winter).

OldDan1943 said:

I also purchased and donated an airplane instrument hood. The school likes to teach the students to believe in their compass and the electronic chart plotter.
Of course, there would also be a spotter to tell the helmsman correction, when in the confined quarters of a single lane bridge and the cribbing..
A word of advice, after you have the compass calibrated.... if you still do not believe your compass, throw the compass over the side. You doubt it once and you will never believe it when desperately need.

Click to expand...

Very good points. Instruments are useless if you don't know how to trust them. Personally, I consider the compass strictly as a backup with current tech. I rely on the COG line and COG heading indication on the plotter far more than the compass, as I typically care more about what direction I'm moving rather than what direction I'm facing. Of course, a cross check to the compass and the laptop (with independent GPS) happens as well just to make sure I'm not being fed bad info.

I love my replacement poly tanks.

I can see the level at any state of running or filling.

We have two 150 gal tanks on each side. The side tanks are connected by a 5/8" valved line, and the port and starboard pairs are connected also. There is only one sight tube per side, on the forward tank on each side. Like above, one inch is 5 gal per tank, so I sit in the ER (with our Ear-Tek headphones), close the connecting valves, and watch the site gauge til almost full, then tell my wife to put the exact same # gal in the other side tank. Repeat on other side. Would love to raise the vents above the fills, but not really possible on our boat.

We had the whistle in the vent line on our last boat and it worked great, as long as you stopped filling the second it changed pitch.

Even a 2 or 3 second delay and you would get fuel coming out of it, though.

Oldersalt said:

Is there any reason the tanks have to be completely full?

Fueling on our boat (GB 32) is a two-person job. The admiral runs the fuel hose while I sit in the engine room watching the sight glass. At about 90 or 95%, I yell at her to stop fueling. I have no problem with not filling the tank to the very top. Never had any problems with condensation or unusual growth in the tank because the tanks are not completely full, though I usually toss in some biocide for good luck.
Oldersalt

Click to expand...

^ this!

We only run our fuel down to 10% to 20% anyway. If you’re cutting it that close, you need larger tanks .

On my Mainship 390, I close the crossover in the bilge, then top each tank using the no-spill with suction cups (pictured in a post above) over the vents. FloScan gives me a good idea how much will be needed. I listen carefully, the change in sound is distinctive, but it's still easy to get a burp at the fill if I'm not careful enough. Open the cross-over, reset the FloScan and I'm on my way.

And, if all the above tips are observed and you still spill a bit of fuel, keep a good quality pump-action spray bottle handy, filled with 50/50 water and liquid Dawn or another good grease-eating detergent, and spray it on the spill. The sheen magically disappears. Well, maybe not if you spill a gallon.

When the nozzle is inserted the fluid does not allow air to escape fast enough. One day I will try to find an old piece of hose that fits into the fill hole and a tight fit on the nozzle. An extender. The thought is if the end of hose is well below top of tank air can get out as fast as fuel is going in and yes you listen for the sound of filling or watch for fluid to come up.

My two tanks voice a load whistle while filling from the vents. As some others have said, as long as you instantly stop fueling when the whistle changes pitch I have no spills.

As for the advice on the spray bottle of dish soap, yes it works well at dispersing the visual aspect of the diesel spill. It does this by sinking it to the bottom. Making the spill actually more detrimental to the environment as diesel quickly evaporates much of the spill relatively quickly if left on the surface of the water.

In Canada, if DFO (fish cops) or the Coast Guard see you spraying soap on a diesel spill you will get fined for the soap as well as the diesel.

In USA you will also get fined.