Does your diesel tank look like this?

[redbeard1]

Hello all,

As the winter winds down here in Chicago, we are busy trying to get our recently purchased (fall 2016) 1993 Ericson 34 in good shape. Recently, we have been trying to figure out why we can only fill our tank to about 80%. We’ve looked at the obvious (calibrate gauge, pump really slowly) but no luck.

A little research has shown me that most tanks have the fuel and vent hoses entering from the top of the tank. Our tank has these two hoses entering from the side (thick black hose with red stripe in picture is for diesel, solid black hose next to that hose is for vent).

It occurred to me that as the tank fills up, both hoses will start to back fill with diesel as well. Could this be what causes the infamous diesel burp to occur on our boat at 80% capacity?

As always, ideas and speculations greatly appreciated.

 

[Christian Williams]

Sorry, not sure what you mean by capacity--rated capacity, gauge reading?

What's the level of fuel in the tank when you remove the fuel gauge or open an inspection port?

 

[redbeard1]

Thanks for reply,

The tank is rated for 30 gallons but we have not had boat long enough to verify. We purchased the boat with fuel gauge showing approximately 90%. On the sail from purchase yard we ran tank down to 65%. We tried to fill it just before storage but were only able to fill it until the gauge showed approximately 80%. At that point, gurgling noises had forced us to slow filling to a trickle. When we saw a spurt of diesel out of the vent we stopped filling. After a motor up river, we stored boat.

Last week, I removed fuel gauge, peeked inside the tank, and saw that the fuel level is approximately 1/2 inch below the level marked B in the new picture. I'm assuming the fuel level goes close to the level marked A but I'm not sure as that would force fuel back into the fill hose. Maybe the top two inches (level A less level B) of the tank are not meant to be used. But if that were the case, why not calibrate the gauge to level B.

Have you ever seen a tank that fills from the side? If so, do you know if those tanks are meant to be filled to the top of the tank or just until the level of fuel reaches the level of the bottom of the fill hose?

Thanks in advance for any help.

 

[EGregerson]

fuel tank

this has been a subject of discussion on posts here. My '87 E34 has '30' gal imprinted on it; But I only get 22 -23 when i tank up. I suspect the over all internal tank dimensions might be 30, but the useful tankage is less; due to the hoses being set down in elevation from the top, and the fuel pickup is an inch or so off the bottom. The 'burp' is due to the fuel hose bending at the bottom, turning 180 degrees and running up slightly to the tank; so i stay away from high speed pumps. When overfull, the excess will run out the vapor hose at the transom. Over the winter I installed a fuel gauge behind the instrument panel; so i can watch the gauge in the cockpit as i fill up. Good luck with your new boat; you'll love it.

 

[JSM]

Redbeard, my diesel tank looks exactly like yours and I am currently in the process of reinstalling it after having it cleaned and new mounting tabs welded on.
Have you pulled the gauge out to see exactly where the fuel level is in the tank ? The gauge in these tanks is relatively simple, just a cork on the end of a rod that drives the gauge. Wouldn't take much to throw it off.
Since the fill and vent hoses are located at the top of the tank, the tank would have to be full for them to back fill.
I also have an E34 that we purchased last May and am in Chicago. PM me if I can help you with anything.
Did you buy "Calypso"?

 

[redbeard1]

JSM
Thanks for the pm offer. We indeed purchased Calypso and so far it’s been a great boat. We were even able to sail her in some wind and she handled great. Typical assortment of small items to fix but I enjoy troubleshooting.

I did remove the fuel gauge to peek into tank. Next time on boat, I’ll try to check if it’s correctly calibrated. When you fill your tank to 100% how many inches do you have from fuel to top of the main part of tank?

Finally, thanks for the picture. We were wondering how the tank looked and now, thanks to you, we’ve got a picture. It is much more shallow than we thought.

 

[redbeard1]

After reading Egregorson's post, I searched this site more carefully and found a posting from 2004 that answered all my questions. Thanks to all.

http://www.ericsonyachts.org/infoexchange/showthread.php?1606-Fuel-capacity-of-E34-(1987)

 

[JSM]

Here's a better picture of the tank. Have never checked the level in the tank after filling but if I recall correctly the gauge does read full. Drawing of the tank rates it for 30 gal. but my tank is placarded for 27 gal. The tank in our boat was manufactured by Racor. YMMV.
Congrats on Calypso, shes a beauty. We were up on that boat twice but it was a bit out of budget for us. Pacific Seacraft really did a nice job on the interior with the light wood.

 

[supersailor]

The supplied gauge is useless in these tanks. It is designed for square or rectangular tanks. The top three inches of this tank holds 14.5 gal. The bottom 3" holds 1 gal. Your sender is off center in the tank so it doesn't read accurately anyway. I have the same tank but with the sender mounted in the low area.

Somewhere on the site I have a thread on the adding of an accurate Centriod sender that is programmed to be accurate for the very shapely tank. The gauge is mounted at my Nav station. I had the tank calced out at one inch intervals to get an accurate calibration for the programmable sender. The sender is $65, the aircraft gauge required is about $50 and there's the hassle of pulling wires. The reward is a useable fuel gauge that you don't have to tear the rear bunk apart to read. The tank calced out to 29.7 gal and mine fills to 29 gal. That burp is indicative of a mostly or totally plugged vent line. There is an air bubble in your tank. The fill and vent are in the side of the tank to allow for that last three inches of fill so you have 14.5 extra gallons. Is it a great way to do it? No, but you double your fuel capacity. Everything in sailboats is a compromise.

Start troubleshooting with your vent line. I found the screen at the stern totally corroded and plugged shortly after I bought the boat. A phillips screwdriver through the screen provided the temporary relief until I could install a new one. Plugged vent lines are also common. If the line looks old, replace it. There also should be no sags in the convoluted route to the stern.

I would recommend taking an hour meter reading when you fill up and use about .75 gal/hr to calc your refuel time. Over time my engine has been using about .5 gal/hr so the .75 gives a safety margin.

 

[Loren Beach]

Hoses?

One point of interest, segueing from Bob's excellent comments...
Several years ago when I replaced all of our fuel system hoses -- fill, engine to and from, and vent, all of the old hose products were either showing some hardening, cracking, swelling, or permeation.
The large fill hose was really ready for replacement.

I put all new hoses in, current USCG approval-marked.

I did indeed replace the metal vent fitting, as well.

All these hoses have a service life, and it's been a long long time since the 80's.
I still like some of that era's music, however!

 

[Christian Williams]

I maintain that fuel gauges on sailboats are unnecessary, at best a psychological palliative, and represent "car thinking". They never provide peace of mind.

The logbook shows how much we have used from the hour meter (Hobbs meter), computed initially at .5/hour (M25) and .75/hour (M40). After a fill, you get your own burn figure.

Anyhow, gauges are never "accurate," even though we get used to what the reading "means."

Ericsons burn fuel so slowly that many fill up only once a season. We never want to run out of diesel under way (which drinks glop at bottom of tank and makes a full air bleed necessary), so most keep the tank topped off and seldom at less than half capacity.

So it is computed fuel burn that really gives peace on mind, not the fuel gauge.

Consider that in general aviation, nobody in his right mind relies on the fuel gauges. Computed and predicted fuel burn is what keeps you alive.

ON my boat, with its 50-gallon tank, I bought the wrong type of fuel sensor--a simple lever arm that rises and falls--horizonal is "full" and hanging straight down is "empty.

I wondered why the readings were weird--it never showed "full".

When I put inspection ports in the tank I encountered the huge baffles inside--which prevented the long gauge arm from rising above half-full.

I cut it in half.

Now it shows "full" but at half-tank remaining, it shows "empty."

I feel much better now, psychologically. "Empty" means only 200 miles of motoring remaining!

Sure, there are other styles of gauge that would work on my tank, but what works best for me is this:

When in existential dread about fuel remaining, I remove the gauge sensor and sound the tank with a marked dowel.

One feels cured of doubt. One feels revitalized with certainty. One feels he has saved $100 for a new fuel gauge.

So, I say use computed fuel burn and consider the fuel gauge decoration.

I admit it is a challenge. But it does encourage keeping the log book up to date.

 

[Emerald]

I also quickly became aware that the dial on my tank had no bearing on what my real quantity of fuel was. So, starting at empty, I added 5 gallons at a time, marking the gauge face for each 5 gallon increase. Gives me a much better reference.

I also have a dowl....

 

[supersailor]

Ah Christian, I like redundancy. It is true that the most accurate way to figure is by engine hours. However, it tends to take forever for the fuel tank to empty. At most I fill up about twice a year (sailing is more fun than stinkpoting). Having a pretty accurate fuel gauge is a reminder for those of us who are mentally lazier to sit down and do the calculation. It's even worse in the San Juan with the new Volvo D1-13 saildrive. I'm not sure what it burns but it doesn't seem to be diesel. It's on the third year on a 19 gal tank. Thinking about emptying the tank into my diesel truck.

The Centroid sender does not have a float and it reads in a non linear, programed sensing. I have to say I'm impressed with it's accuracy. Of course, you don't get a good reading if the boat's heeled 30 degrees or if there's a huge slop out. The time to read it is before you leave the dock to ensure you have enough fuel for the trip. The sender supplied by Ericson is worse than having none at all. Mine read full at half a tank and 1/4 with only a gallon left. Also, it was located under the aft double berth.

I have to admit that paperwork is not my best strength. Keeping up the Log Book kinda falls by the wayside too often. What I found works is I write the engine hours and amount of fuel on a small piece of paper and stick it just above the electrical panel so it is in my face. It also gets me to calculate the fuel consumption each time I fill up.

I am quite happy with the way the gauge turned out and it does remind my to calculate the fuel burn periodically. Hopefully I can blame my occasional lapses on "Senior Moments".

 

[Christian Williams]

Yes, the Centroid was the sensor I shoulda bought, instead of the goofball 19"-long swing arm type.

Can you get it to read a trapezoidal tank? Perhaps by filling-from-empty and manually programming the gauge?

 

[supersailor]

I had two choices. Send the engineer the tank dimensions and let him calculate the tank dimensions ($100) or fill the tank by eights and send him the amounts so he could program the sensor (free). I had more money than time and hauling all that diesel below and pouring it into the tank was not appealing so I paid to have the tank measured. That is now done for the 34. Anyone can now go to Centroid and get a sender properly programmed without the measuring charge. Unfortunately, the 38 has a different tank and would need different programming. A model of the Centroid is made that would allow programming in the field. Too complicated for me.

 

[Grizz]

Mystery Fuel Gauge Markings

The 'mystery' isn't the markings, it's where the explanation of what they mean is filed. It's not 'lost', it just hasn't been found. Friends that golf say they use that justification on the course, especially if there's $ at stake...

This O-34 has a 14 gallon tank fueling the M25-XP. As Christian observed, this gauge is essentially worthless, serving mostly as a means to fill the hole in the nav station. Much more accurate is the relationship between RPM and GPH, we using 2800 = 1 GPH as the benchmark and adjusting the GPH up...or down, from that point, depending on the increase/decrease in RPM.

Our annual return passage from Mackinac (@ 300 nm to Chicago), 90% of it spent motoring (either no wind or wind on the nose), settles in like this: we depart, noting the time, motor for 6 hours, pull 1 of the (4) 5-gallon jerry cans on deck (filled on the island, not easily or inexpensively), dispense using the Ready Siphon hose in less than 4 minutes, all in, stash the empty and the Siphon in the cockpit lazarette, note the time of re-fueling and press on. Easy. Repeat as needed.

It's believed the 'intermediate marks' on the blue tape are 5-gallon refilling marks, but until the explanation is found, it'll remain a mystery. It IS known that the Far Right mark = Full, translating 'Empty' on the gauge to 1/4 tank remaining, "ish", which further translates to @ 3 gallons remaining. Another 'ish'.

During the season, in & around harbor, 1/4 filled on the gauge (translating to @ 1/2 full in reality), is the target. It's time for another gallon (or 2) when it ducks between E and 1/4 on the dial. It's a system that's evolved over time, so far, so good.

 

[bgary]

The logbook shows how much we have used from the hour meter (Hobbs meter), computed initially at .5/hour (M25)

+1

Logbook says I motored about 18 hours in 2016. And end-of-season fill was about 8.5 gallons. That's a good datapoint.

Logbook also says Makana and I were out on the water together 51 times in 2016, and I estimate I was on the boat "just for fun" (often with an adult beverage and a good book) another 30 or so.

I'm planning to improve those datapoints in 2017...

 

[HerbertFriedman]

While I have not kept good diesel records, the previous owner kept records over 10 years and records a consistent 1/3 gal/hour on my M25XP. He always went to a gas dock to refill while I just add 5 gal every 15 hours or so using a jerry can. Question, how does one know that the tank is filled at a gas dock, does the pump automatically shut of or do you wait for some spillage out the vent? I am hesitant to just fill manually until diesel comes out the vent.

 

[Christian Williams]

The only way I know to assure a 100 percent full tank is to fill until diesel shows in the fill hose, or you can hear it gurgle. Takes a long time, going slowly, with an absorbent pad ready.

This leaves me with a full fill hose, so I do it on the way out of the marina so as to burn that first.

 

[Grizz]

Beware Impatient Pump Jockies

I'll note Christian's recommendation of 'going slow' to fill and to have an absorbent pad nearby. Pump pressure at fuel docks vary greatly, testing the vent capacity, fuel blowback the byproduct, especially when there's an audience. This is most likely to happen after recommending to the Jockey to 'take it slow and easy'. There's small consolation in the "I told you so" when the deck is splattered and the water shimmers. Not good.