Diesel Bug

[Tom]

No Comparison boats to airplanes

The biggest difference is fuel comsumption. even a little cessna 172 burns7-9 gallons/hor and carries about 36 gallons. In my old flying club we would burn 100 gallons or more a month. Also airplanes burn gasoline and have drains at the sump in the tanks. BTW in several years of flying it was rare to get more than a few drops of water when checking the fuel. It was always after a rain. The cap is in a small depression and water would collect around the cap. The only problem with believeing that water comes from condensation is that you won't check the o-rings in your fill cap or check the fuel that you are puting into your tank .And if your boat is like an airplane and goes through several tanks of fuel a month you don't have to worry about old fuel. But if you are like me and use a gallon of fuel a month it makes no senseto carry around several years worth of fuel...unless you want to grow diesel bugs.

 

[Monty Miller]

An ounce of prevention

I'm from the side of the camp that is very concerned about fuel source. I always buy fuel from a high turnover car service station and use a diesel filter funnel that filters out impurities and water. It's slow to fill and for every 5 gallons there are several tablespoons of something the filter collects. I use a biocide and consume only 10 gallons of fuel a year. So far, no problems.

 

[Big Windy]

Fuel

Pardon the pun, Tom, but your comments do not hold water. Condensation forms (as mentioned above) from the boat/airplane being outside and continuously going from hot to cold and back again, and having a place to condense...a partially empty tank. As far as fuel burn, it is all relevant...big tank high fuel burn, small tank low fuel burn. I've been flying/boating for a number of years, and every publication I have read says keep the tanks topped off (unless the boat/airplane is out of the weather)...including the Yanmar manual on my current boat and the manuals on the airplanes I fly. As for bugs, that's what the Biocide is for, and it works.

 

[RichH]

Aircraft tank have a 'bottom drain' ....

Its easy to drain any water from an aircraft fuel tank; every time you do your 'pre-flight' you open the bottom cock to be SURE that there is NO water on the bottom of the tank. However by the CG rules NO marine fuel tank may have a bottom drain .... so it doesnt leak and cause a 'sheen' when you forget to close the cock. BIG difference between aircraft tanks and boat tanks.

 

[Gord May]

Some good references

”Long Term Storage of Diesel Fuel”: (from BP Australia)http://www.bp.com.au/fuelnews/ADF1402.pdf6-12 months at temps of 30* C or higheror12 months or longer at 20 degrees C or LOWERAn excellent article !!!“Diesel Fuel - Fungal Contamination”:http://www.bp.com.au/fuelnews/ADF1502.pdfThis deals specifically with diesel fuel used in boatsSee also: BP Australia - Fuel News Topicshttp://www.bp.com.au/products/fuelnews/topics.aspIncluding “Common Diesel Problems”(1) http://www.bp.com.au/fuelnews/ADF0907.pdf(2) http://www.bp.com.au/fuelnews/ADF1006.pdf(3) http://www.bp.com.au/fuelnews/ADF1107.pdfand more ...

 

[p323ms]

A simple experiment

Since I am a scientist and former science teacher I like experiments. Take a gallon fuel can and put a quart of diesel (water free of high quality) in the can. Leave the vent open and set the can securely in your boat where water cannot get into it from rain etc. After a couple of months pour the fuel out and measure the water!!!! For a control set a full can next to the 1/4 full can. Anecdotally I've never noticed water accumulating in my lawn mower's gas tank unless I forget and leave the mower out in the rain. The references to aircraft is also interesting in that the PO of my boat is a pilot for Northwest airlines and he is the one who advised me to only keep enough fuel for immediate use in my tank to avoid contamination. The most important thing in airplanes is probably "don't ever run out of fuel" but I've read articles on aircraft fuel management advocating flying with less than full tanks to increase payload and decrease fuel consumption. So if you are near your maximum take off weight having 20 gallons less fuel allows you to carry another person. Or if you are flying 100 miles and only need 10 gallons of fuel why carry full tanks which make your takeoffs longer and climb rate slower. ?? For non pilots; The heavier your load the more fuel you have to burn to fly and the higher your required take off speed. My previous boats all had outboards and since water in their fuel had not been a problem I'd never considered diesel contamination.  After teaching high school physics and math for a year I came to realise that some people have a great deal of difficulty understanding science and math. I also realised that I wasn't cut out to be a teacher.TomPS for Gord May... I am advocating that we sailers avoid long term fuel storage. Fresh is better!!!

 

[Gord May]

condensation IS a problem

I think you’ll see why I agree /w p323ms , and don’t recommend long-term fuel storage (lts); if you read ”Long Term Storage of Diesel Fuel” at http://www.bp.com.au/fuelnews/ADF1402.pdfIt’s only 3 pages, and describes the hazzards to fuel quality (of lts), as well as some the mitigation measures.Gord