Hey Guys, I just wanted to share an experience I had a few weeks ago. I was heading out on my first big cruise to go from Boston to Hyannis for the Figawi race. I'd taken the boat out twice immediately after launching to make sure all systems survived the winter, but about 25 minutes out on my big cruise my engine (a 2001 Yanmar 2GM20F) sputtered, surged & stalled. I quickly diagnosed there was air in the fuel so I bled the system, got it running for 5 minutes & it quit again. I had a hard deadline to get to the race so I sailed the entire way from Boston to Sandwich on the Cape Cod Canal (docking under sail!) and then sailed out & from Sandwich to Hyannis. I made it to the race on time, but it was a royal pain in the neck. I figured it was bad fuel, but I changed filters 3 times & every time it ran for about 5 minutes & then quit. I started to second guess my "bad fuel" diagnosis, but because the engine was so new (less than 200 hours) I couldn't imagine that an injector or fuel pump or any other mechanical problem could exist. It turns out that the fuel additive I used in the fall for winter layup didn't include a biocide. I had a plankton bloom (diesel bug) in my fuel and there was a LOT of sediment in the fuel. It caused a brand new set of fuel filters to be clogged in about 5 minutes. I couldn't believe it. I ended up pumping out about 12 gallons of old fuel, adding biocide to the empty tank to shock the system & filling with fresh diesel. It now runs perfectly. I'm sharing this story with you guys so you can learn from my mistake. Make sure you take care of your fuel including both a fuel stabilizer AND a biocide additive. A set of filters set me back $33 and I went through 5 of them when all was said & done, along with the headache of worrying about the reliability of my engine. Happy Sailing to All, Allen Schweitzer s/v Falstaff C-30 Hull# 632
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Thanks for Sharing
Hi allen - thanks for sharing. One question - When was the last time you flushed your tank clean? How old is the tank? I don't put anything in my tank other than topping it off in the fall for winter layup. I removed my tank 2 seasons ago and had it steam cleaned- I guess I am on borrowed time.
Hi allen - thanks for sharing. One question - When was the last time you flushed your tank clean? How old is the tank? I don't put anything in my tank other than topping it off in the fall for winter layup. I removed my tank 2 seasons ago and had it steam cleaned- I guess I am on borrowed time.
Same Problem !
Allen, I ran into the same problem two weekends ago while travelling from Sidney, B.C. to Oak Bay, a 4 hour run. Weather forecast was small craft warning which did not change on the radio however things went to 45 knot winds and 15 foot waves along the way.(Small freighter warning maybe) I had an algea problem last fall in the tank and used the biocide stuff to cure the problem over the winter. Trouble is it sort of killed a lot of it and in the big seas it stired it all up and bingo the Racor is clogged. Whole other story on how I got home. I ended up taking approx 12 gallons of diesel out of the tank and took it to a recycling place and then having to cut the fiberglass holding the aluminum tank out. The tank was taken to a shop and cleaned out. (Worst algea problem they had ever seen in a tank) I am just finishing glassing in the cleaned tank and have devised a secondary fuel system using a a smaller outboard fuel tank with a filter that I can disconnect/connect in place of the main diesel fuel tank. Cliif Carter PlusOne C30 #598 Oak Bay, B.C.
Allen, I ran into the same problem two weekends ago while travelling from Sidney, B.C. to Oak Bay, a 4 hour run. Weather forecast was small craft warning which did not change on the radio however things went to 45 knot winds and 15 foot waves along the way.(Small freighter warning maybe) I had an algea problem last fall in the tank and used the biocide stuff to cure the problem over the winter. Trouble is it sort of killed a lot of it and in the big seas it stired it all up and bingo the Racor is clogged. Whole other story on how I got home. I ended up taking approx 12 gallons of diesel out of the tank and took it to a recycling place and then having to cut the fiberglass holding the aluminum tank out. The tank was taken to a shop and cleaned out. (Worst algea problem they had ever seen in a tank) I am just finishing glassing in the cleaned tank and have devised a secondary fuel system using a a smaller outboard fuel tank with a filter that I can disconnect/connect in place of the main diesel fuel tank. Cliif Carter PlusOne C30 #598 Oak Bay, B.C.
I would think about buying fuel!!!
From a reputable source!!! Unless you have some kind of leak letting in a lot of water. The small tank makes sense but not as a backup. Keep the larger tank empty and only fill it when needed for a longer cruise. Instead of adding biocides empty the fuel tank at the end of the season. Never have fuel over a year old. Alternative would be to keep only enough fuel for a month in the large tank. My target is 1/4 tank in a 20 gallon tank. 5 gallons will run most small diesels a long time. Tom
From a reputable source!!! Unless you have some kind of leak letting in a lot of water. The small tank makes sense but not as a backup. Keep the larger tank empty and only fill it when needed for a longer cruise. Instead of adding biocides empty the fuel tank at the end of the season. Never have fuel over a year old. Alternative would be to keep only enough fuel for a month in the large tank. My target is 1/4 tank in a 20 gallon tank. 5 gallons will run most small diesels a long time. Tom
Low fuel
I was out last weekend on a freedom with only 6 gallons. Started the engine on the way in when we were heeled over. The combination of the heel and low fuel caused the engine to suck in air and empty out the fuel line and filter. It look us a little over an hour to figure out what went wrong and get the engine running again.
I was out last weekend on a freedom with only 6 gallons. Started the engine on the way in when we were heeled over. The combination of the heel and low fuel caused the engine to suck in air and empty out the fuel line and filter. It look us a little over an hour to figure out what went wrong and get the engine running again.
Follow ups...
Hey Guys, It's good to know that I'm not the only one with this problem!! As for the amount of fuel to keep in the tank, all experts I've consulted recommend keeping the tanks full in northern climates during the winter to prevent condensation. Maybe in warmer climates you're better off with 1/4 tank to keep fuel from getting old, but not in New England. My tank was completely cleaned and all new fuel lines & filters installed when I repowered in 2001, so the fuel system is not that old. I filled an almost empty tank in October, about 1 month before hauling for winter storage so the fuel wasn't that old, either. As part of my diagnostics I took off the fuel line aparatus to peek into the tank & it looked spotless. The message here is that you need 3 things: (1) full tank, (2) biocide AND (3) stabilizer. If you forget one of those 3 elements, you're inviting trouble. --Allen
Hey Guys, It's good to know that I'm not the only one with this problem!! As for the amount of fuel to keep in the tank, all experts I've consulted recommend keeping the tanks full in northern climates during the winter to prevent condensation. Maybe in warmer climates you're better off with 1/4 tank to keep fuel from getting old, but not in New England. My tank was completely cleaned and all new fuel lines & filters installed when I repowered in 2001, so the fuel system is not that old. I filled an almost empty tank in October, about 1 month before hauling for winter storage so the fuel wasn't that old, either. As part of my diagnostics I took off the fuel line aparatus to peek into the tank & it looked spotless. The message here is that you need 3 things: (1) full tank, (2) biocide AND (3) stabilizer. If you forget one of those 3 elements, you're inviting trouble. --Allen
It could have had bad fuel from the beginning.
The fuel could have been bad from the pump. The very first statement the teacher told us when I took my diesel course was "Always treat any fuel as suspect". Meaning that you can get bad fuel from anywhere, anytime. Judging from the amount of algae you described, it may have already been in the tank when you stored the boat. So don't blame the algaecide.
The fuel could have been bad from the pump. The very first statement the teacher told us when I took my diesel course was "Always treat any fuel as suspect". Meaning that you can get bad fuel from anywhere, anytime. Judging from the amount of algae you described, it may have already been in the tank when you stored the boat. So don't blame the algaecide.
Full fuel tanks is a bad idea!!!!
Well maybe not if you are heading to the Bahamas for a couple of months. Condensation is a myth!!! Look at the physics and do the math. A very small amount of water might get into fuel by condensation but not much. But also look at the logic if you drain your tank at the end of the year it should be perfectly dry in the spring as you remove the water with the fuel. And more importantly you can put fresh clean dry fuel in it just before it splashes. Also to argue against a full tnak is the fact that old fuel is a constant source of contamination or new fuel. That's the way we grow bacteria in the lab!! Take a small amount of bacteria and add it to fresh sterile culture media. Even at home when I was making beer a little bit of the old beer or beer sediment is added to the fresh sterile malt to make new beer. Also since free water sinks adding fresh fuel does nothing to dry out the tank. As to sucking air maybe a small header tank of a gallon or two to catch the air before it gets to the engine. Tom PS It would be simple thing to put a length of metal tube at the distal end of the vent line and stuff it with brass wool have it go vertical from the vent hole for a foot. Then any condensation should drip back out the vent hole instead of getting into the tank.
Well maybe not if you are heading to the Bahamas for a couple of months. Condensation is a myth!!! Look at the physics and do the math. A very small amount of water might get into fuel by condensation but not much. But also look at the logic if you drain your tank at the end of the year it should be perfectly dry in the spring as you remove the water with the fuel. And more importantly you can put fresh clean dry fuel in it just before it splashes. Also to argue against a full tnak is the fact that old fuel is a constant source of contamination or new fuel. That's the way we grow bacteria in the lab!! Take a small amount of bacteria and add it to fresh sterile culture media. Even at home when I was making beer a little bit of the old beer or beer sediment is added to the fresh sterile malt to make new beer. Also since free water sinks adding fresh fuel does nothing to dry out the tank. As to sucking air maybe a small header tank of a gallon or two to catch the air before it gets to the engine. Tom PS It would be simple thing to put a length of metal tube at the distal end of the vent line and stuff it with brass wool have it go vertical from the vent hole for a foot. Then any condensation should drip back out the vent hole instead of getting into the tank.
8 tea spoons in 264 gallons
I checked some tables and did a little math. If you had a completely empty tank of 264 gallons at 100% humidity at 90+ degrees C there would be about 8.1 teaspoons of water.If it dropped to zero C that night and your tank got that cold about 7 teaspoons of water would precipitate. Not much!!!! It is not often that you have 100% humidity days near 90 and frost that night!! With less temperature and humidity there is a lot less water in air. Tom
I checked some tables and did a little math. If you had a completely empty tank of 264 gallons at 100% humidity at 90+ degrees C there would be about 8.1 teaspoons of water.If it dropped to zero C that night and your tank got that cold about 7 teaspoons of water would precipitate. Not much!!!! It is not often that you have 100% humidity days near 90 and frost that night!! With less temperature and humidity there is a lot less water in air. Tom
It Does Not Need to Get That Cold
It only needs to get down to the dew point. If you only collected two teaspoons a night that is a cup and a half each month. Just think of all that condensation you wipe off of the outside of your boat the same thing happens on the inside of the unfilled portion of the tank. I'd rather have old diesel and no water than fresh diesel with water. Do as you wish my tank will stay full. Here is what John Deere says: http://manuals.deere.com/omview/OMT185542_19/TX_10_DH3377_19_30JUN94_1.htm and Don Casey: http://www.boatus.com/boattech/casey/33.htm
It only needs to get down to the dew point. If you only collected two teaspoons a night that is a cup and a half each month. Just think of all that condensation you wipe off of the outside of your boat the same thing happens on the inside of the unfilled portion of the tank. I'd rather have old diesel and no water than fresh diesel with water. Do as you wish my tank will stay full. Here is what John Deere says: http://manuals.deere.com/omview/OMT185542_19/TX_10_DH3377_19_30JUN94_1.htm and Don Casey: http://www.boatus.com/boattech/casey/33.htm
Full tank is a bad idea #2
Chemical equilibrium is such that with changing temperature (to lower temps) will be such that the emulsified (bound) water will separate out and settle to the bottom. A less than full tank will (again by equilibriium) condense water vapor on the tank walls, forming 'free' water .... will settle to the bottom. The condensation is going to form ON the surface of the oil in the tank if the oil is colder than the ambient air. Take your pick .... you are going to get water in *either* case. Water at the bottom of the tank will supply the background bacteria (living at the interface between the water and the oil .... using the oil as its nutrient source) to flourish and cause agglomeration and growth of particulate. Unless you use the oil on a high volume turnover basis, you're gonna incubate bacteria, agglomerate particles (smaller particles growing into larger and larger particles. When taking fuel from a 'questionable' supply I run the recirculation system into a parallel filter that contains a 'water absorbing starch' (hydroxymethylcellulose) to remove the emulsified water. A refinery only filters down to about 5-10µM at best .... and then these particles begin to stick together (agglomerate) into larger particles over time. The sure remedy is to use a seconday dip tube that goes ALL THE WAY TO THE BOTTOM and run it through a recirculation/polishing filter with a water 'knock-out-pot' (gravity settling - outside the tank). The benefits of a recirculation/polisher if used constantly when the engine is running is be to remove the 'background' particles and bacteria to such a low level so that they (both) wont agglomerate/grow .... inside the tank. A constantly recirculating filter system (typical µM rating @ 10-15µM will typically yield *sub-micronic* resident particles in the tank. .... and then you will hardly ever need to change your Racors, etc. I buy my fuel ONLY from high turn-over sources (where the watermen buy their fuel, etc.) so that I dont have to worry about the accumulated crap, particles, water, etc. that you get from a mom & pop ..... fuel oil has a relatively short shelf life - once it begins to 'particulate'. I keep the MINIMUM amount of fuel on board (plus a safety reserve) ..... and most importantly have a *valve on the vent line* which I close when Im not using the boat ...... to prevent water vapor/condensation ingress. CG regs. require that a fuel tank doesnt have a bottom drain. OK, thats not being sensible for 'my' operating mode to drain such water .... I simply suck it out and remove it in a recirculation system. BTW ... I have large black iron tanks and I also run from a 3 gallon 'day' tank. I havent changed my Racor final filter in over 6 years. My fuel is always 'crystal clear'. I will email a schematic of my fuel system if anyone wants it. RhmpL33ATattDOTnet
Chemical equilibrium is such that with changing temperature (to lower temps) will be such that the emulsified (bound) water will separate out and settle to the bottom. A less than full tank will (again by equilibriium) condense water vapor on the tank walls, forming 'free' water .... will settle to the bottom. The condensation is going to form ON the surface of the oil in the tank if the oil is colder than the ambient air. Take your pick .... you are going to get water in *either* case. Water at the bottom of the tank will supply the background bacteria (living at the interface between the water and the oil .... using the oil as its nutrient source) to flourish and cause agglomeration and growth of particulate. Unless you use the oil on a high volume turnover basis, you're gonna incubate bacteria, agglomerate particles (smaller particles growing into larger and larger particles. When taking fuel from a 'questionable' supply I run the recirculation system into a parallel filter that contains a 'water absorbing starch' (hydroxymethylcellulose) to remove the emulsified water. A refinery only filters down to about 5-10µM at best .... and then these particles begin to stick together (agglomerate) into larger particles over time. The sure remedy is to use a seconday dip tube that goes ALL THE WAY TO THE BOTTOM and run it through a recirculation/polishing filter with a water 'knock-out-pot' (gravity settling - outside the tank). The benefits of a recirculation/polisher if used constantly when the engine is running is be to remove the 'background' particles and bacteria to such a low level so that they (both) wont agglomerate/grow .... inside the tank. A constantly recirculating filter system (typical µM rating @ 10-15µM will typically yield *sub-micronic* resident particles in the tank. .... and then you will hardly ever need to change your Racors, etc. I buy my fuel ONLY from high turn-over sources (where the watermen buy their fuel, etc.) so that I dont have to worry about the accumulated crap, particles, water, etc. that you get from a mom & pop ..... fuel oil has a relatively short shelf life - once it begins to 'particulate'. I keep the MINIMUM amount of fuel on board (plus a safety reserve) ..... and most importantly have a *valve on the vent line* which I close when Im not using the boat ...... to prevent water vapor/condensation ingress. CG regs. require that a fuel tank doesnt have a bottom drain. OK, thats not being sensible for 'my' operating mode to drain such water .... I simply suck it out and remove it in a recirculation system. BTW ... I have large black iron tanks and I also run from a 3 gallon 'day' tank. I havent changed my Racor final filter in over 6 years. My fuel is always 'crystal clear'. I will email a schematic of my fuel system if anyone wants it. RhmpL33ATattDOTnet
Biocide and Condensation
Biocide only kills the bug where it settles to the bottom of the tank waiting to clog your filters. I use "Fuel Set" from Australia. This re-dissolves the bug which then passes through the filters and pumps and burns in the engine. Condensation results when the tank inhales cool damp air through the vent every evening which then condenses a minute amount of water. Next morning it exhales the now less moist air. Continue this cycle for many months and .... I still believe we pay good money for the water and get it from the suppliers fuel tanks. My chum in UK says a good fuel station will clean its tanks once every two years, a bad one - never. The oil companies require storage tanks to be cleaned every 3 months. Hence our problems.
Biocide only kills the bug where it settles to the bottom of the tank waiting to clog your filters. I use "Fuel Set" from Australia. This re-dissolves the bug which then passes through the filters and pumps and burns in the engine. Condensation results when the tank inhales cool damp air through the vent every evening which then condenses a minute amount of water. Next morning it exhales the now less moist air. Continue this cycle for many months and .... I still believe we pay good money for the water and get it from the suppliers fuel tanks. My chum in UK says a good fuel station will clean its tanks once every two years, a bad one - never. The oil companies require storage tanks to be cleaned every 3 months. Hence our problems.
Tank is warmer than the air
If you think about a typical 24 hours and a boat in the water. Near dawn coolest outside air with the least amount of water/liter highest trelative humidity. Tank warmer than air. mid afternoon warmest time of day with the most absolute water content lowest relative humiduty tank cooler than air but...full of cool dry air so almost no air flow. evening air cooling condensation occuring but tank warmer than air so no air intake. Later as the tank cools it takes in a small amount of air that has a much reduced water content. Remember that a tank is a closed system with only the vent tube open to outside.The outside of a cold tank cools the surrounding air which condenses water and importantly the cooler air falls bringing in more warm moist air. This doesn't occur inside the tank. Cool dry air is heavier than warm moist air so no bulk exchange happens only a little diffusion. My experience here on the gulf coast with the boat in the water year round has been only about a teaspoon of water in the water separator in almost two years. I do use biocide and sometimes a cetane booster. The idea of a full tank is just an old wives tale that keeps being repeated. But logic says that clean fresh fuel should be better than fuel that is old. Part may be stink potters who probably use several tanks of fuel a year. But many sailboaters don't use a tank of fuel in 2 or three years. Typically in day sailing I run my engine less than an hour which is about a quart of fuel. Maybe 4 days a month or a gallon a month. One guy with a small yanmar said that he only burns about a pint an hour. It is also a good safety factor for a stinkpotter to have a full tank as they don't move unless the engine is running. Tom
If you think about a typical 24 hours and a boat in the water. Near dawn coolest outside air with the least amount of water/liter highest trelative humidity. Tank warmer than air. mid afternoon warmest time of day with the most absolute water content lowest relative humiduty tank cooler than air but...full of cool dry air so almost no air flow. evening air cooling condensation occuring but tank warmer than air so no air intake. Later as the tank cools it takes in a small amount of air that has a much reduced water content. Remember that a tank is a closed system with only the vent tube open to outside.The outside of a cold tank cools the surrounding air which condenses water and importantly the cooler air falls bringing in more warm moist air. This doesn't occur inside the tank. Cool dry air is heavier than warm moist air so no bulk exchange happens only a little diffusion. My experience here on the gulf coast with the boat in the water year round has been only about a teaspoon of water in the water separator in almost two years. I do use biocide and sometimes a cetane booster. The idea of a full tank is just an old wives tale that keeps being repeated. But logic says that clean fresh fuel should be better than fuel that is old. Part may be stink potters who probably use several tanks of fuel a year. But many sailboaters don't use a tank of fuel in 2 or three years. Typically in day sailing I run my engine less than an hour which is about a quart of fuel. Maybe 4 days a month or a gallon a month. One guy with a small yanmar said that he only burns about a pint an hour. It is also a good safety factor for a stinkpotter to have a full tank as they don't move unless the engine is running. Tom
lots of diverse views
It's interesting to see how strongly people feel about such a diverse viewpoint as fuel tanks. I suspect everyone is partly correct but fail to mention the most likely source of water in the tank - a bad o-ring on the fill cap allows water to enter at a far greater volume than any amount of condensation. Don
It's interesting to see how strongly people feel about such a diverse viewpoint as fuel tanks. I suspect everyone is partly correct but fail to mention the most likely source of water in the tank - a bad o-ring on the fill cap allows water to enter at a far greater volume than any amount of condensation. Don
Fill Cap
The new hunters have a fill cap on a slant so MOST water doesn't hang around to seep in. Do the older hunters also have this?
The new hunters have a fill cap on a slant so MOST water doesn't hang around to seep in. Do the older hunters also have this?
P323ms do not agree
Dew forms overnight - contrary to your reasoning. Tank cools overnight. Cooling air contracts so tank breathes in outside air. Reverse occurs during daytime. Tanks certainly breathe at every temperature change and it matters little whether the outside air is warmer or colder. Changes of barometric pressure can also result in 5% of the volume of air above the fuel being exchanged. Consider cumulative effect over, say, 3 years of both causes and include air taken in as fuel is used. Air only 2' above water is bound to have high humidity. Any high humidity air will condense some water when cooled below dew point. However I do agree that the gallon or so of water I have had in my fuel tank on two occasions was purchased as diesel. As said in my previous posting.
Dew forms overnight - contrary to your reasoning. Tank cools overnight. Cooling air contracts so tank breathes in outside air. Reverse occurs during daytime. Tanks certainly breathe at every temperature change and it matters little whether the outside air is warmer or colder. Changes of barometric pressure can also result in 5% of the volume of air above the fuel being exchanged. Consider cumulative effect over, say, 3 years of both causes and include air taken in as fuel is used. Air only 2' above water is bound to have high humidity. Any high humidity air will condense some water when cooled below dew point. However I do agree that the gallon or so of water I have had in my fuel tank on two occasions was purchased as diesel. As said in my previous posting.
Reddevile
I run a 3-53 detroit diesel in my boat. I have 75 gal fuel tanks and have never had a problem with water or bug. Long ago I learned an old trucker trick, add a quart of Reddevile to the tank and forget it. It keeps fuel clean and ready for use. The only time I change fuel filters is when I do my six month maintaince.
I run a 3-53 detroit diesel in my boat. I have 75 gal fuel tanks and have never had a problem with water or bug. Long ago I learned an old trucker trick, add a quart of Reddevile to the tank and forget it. It keeps fuel clean and ready for use. The only time I change fuel filters is when I do my six month maintaince.
Fuel Tanks
Airplanes keep the the tanks filled (even if the plane will be sitting for a long time) to keep condensation from forming. Same applies to boats.
Airplanes keep the the tanks filled (even if the plane will be sitting for a long time) to keep condensation from forming. Same applies to boats.
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