Winterization of Marine diesel tank and service of engine.

sailme88 · Nov 29, 2019

Good time to add a diesel fuel additive that kills/prevents algae and increases lubricity. After adding, fill the tank. This action will allow the additive to fully mix. A full tank of fuel leaves less room for condensation. .You might want to release all water lines from tanks and introduce RV antifreeze throughout for plumbing lines.

jssailem · Nov 29, 2019

Regarding fuel, it is a personal choice and depending on the age of the fuel, the source of the fuel, and your local conditions. I’d ask your local mates in the marina or a commercial fishing captain what he does. They would know.
I find that if you have any water in the fuel you will get algae growth. The addition of an additive will help to battle this. Also have fuel filters available for when you start the season.

With regards to oil changes I choose to do it in the fall so come spring I am ready to go. Unless I have complications then I do it in the spring. Fresh start to the season.

NYSail · Nov 29, 2019

With the engine many times I service on land. I use a large plastic storage bin with a hose supplying fresh water.
Regarding fuel tank there are two schools of thought. Fill to help prevent moisture in tank or keep minimal fuel so you don’t havr old fuel. I keep minimal fuel in tank and add fresh in the spring. I have a racor 500 water separator to eliminate water issues but have never had to deal with water in fuel in 20+ years of boat ownership.
Don’t forget the fresh water supply system in the boat. If that freezes you will be facing a tremendous amount of work with broken hoses, pumps, strainers and fixtures.

Good luck

TomY · Nov 29, 2019

I wouldn't worry about the fuel if I were you. You're in a colder climate like mine here on the coast of Maine. I don't use any algae growth additives and have never had growth problems. Last time I took a sample from the bottom of my 80 gallon tank, it was crystal clear. The tank winters over at anywhere between 1/2 to full-ish the last 20 years.

Just be sure to double check that the yard winterizes any systems that would be damaged by freezing. You'll then have a list of those items for the future.

I wouldn't bother with the oil change now as you'll have to re-winterize the engine. Like others, I do that in the fall mostly because it's ready in the spring.

Congratulations on your new boat!

TimFromLI · Nov 29, 2019

Interesting article here on fuel tanks and condensation. Even so, I still try to fill it and use an additive- while the weather is still warm. Most important is making sure the O-ring at the deck fill cap is replaced when needed.

The Myth of Condensation in Fuel Tanks: Need a Full Fuel Tanks to Store or Lay-up Your Boat? - Boat Maintenance - by David Pascoe

Frequently we hear it said that the cause of water in fuel tanks is due to condensation. I have long doubted this assertion but the issue has come up so frequently that I was finally motivated to try prove to the point.

www.yachtsurvey.com

dlochner · Nov 29, 2019

Let's first correct a myth, algae does not grow in diesel fuel tanks. Algae requires light to grow and prosper, so unless the tank is translucent and sitting in the sun, algae is not your problem.

Microbes are the issue. These grow in the interface between moisture in the tank and fuel, using the fuel as a food substance. These microbes are a problem in a couple of ways, their dead bodies clog fuel filters and their by-products are acidic and can corrode aluminum. The microbes are anaerobic and produce sulfur dioxide and sulfuric acid. These are the same kind of bugs that cause obnoxious sulfur odors from the holding tank. Show these bugs no mercy. Search for Microbiologically Induced Corrosion for a more thorough discussion of the bad things these little critters can do.

Recent testing by @thinwater for Practical Sailor has found that Biobar JF was the most effective biocide. Diesel Additives - Practical Sailor Print Edition Article.

A water separating filter will keep water out of the fuel line before it reaches the engine. However, it is likely that the fuel pickup tube is a few millimeters above the tank bottom, so it will only remove water that reaches the bottom of the tube or higher. That still allows the critters to grow and prosper.

To answer the OP's question, it is good practice to keep the fuel tank as full as possible through out the year. This limits the amount of condensation that can occur even in the summer. Alternatively, adding a vent filter with a desiccant in it will help to keep moisture out of the tank.

dlochner · Nov 29, 2019

TimFromLI said:
Interesting article here on fuel tanks and condensation. Even so, I still try to fill it and use an additive- while the weather is still warm. Most important is making sure the O-ring at the deck fill cap is replaced when needed.

The Myth of Condensation in Fuel Tanks: Need a Full Fuel Tanks to Store or Lay-up Your Boat? - Boat Maintenance - by David Pascoe

Frequently we hear it said that the cause of water in fuel tanks is due to condensation. I have long doubted this assertion but the issue has come up so frequently that I was finally motivated to try prove to the point.

www.yachtsurvey.com

Pascoe's point about water in fuel tanks coming from sources other than condensation is well taken. However, I think he over states his argument against condensation. It is unlikely that in a single season enough condensation would occur to cause issues with the fuel supply to the engine, however, over time even a fraction of an ounce a year adds up. He also doesn't mention the bigger issue with water in the fuel tank, the little critters that grow on the fuel water interface. These guys don't need much water and the water level may be well below the pickup tube.

dLj · Nov 29, 2019

Dlochner is spot on. MIC is very much a concern with diesel. No one ever runs a diesel tank dry. So there is always a small amount, at least, left when refilling. If you are going through a lot of diesel, you probably don't have much to worry about. But, like in my case where I don't even go through one entire tank of fuel in a year, putting in a biocide is a good idea. In the OPs case, the boat is new and knowledge of what the fuel usage has been is likely unknown. I would not worry about draining the tank. Putting in a sabilizer as others above have mentioned would be prudent.

As far as performing oil change on the motor at this point since the marina is winterizing the engine, just let it be. It will be fine. Most folk here do their oil changes in the fall when putting the boat up, I don't. I do it in the spring before launching. I have too many things going on in the fall and don't have the time then. But I have a nice block of time before launch where I do all my boat projects for the year, including engine maintenance. So that's when I perform this work. I also don't use the motor a lot during the sailing season, I sail. To give you an idea, I've used 1/2 of a tank of fuel in two years. My tank is a 12 gallon tank. I sail almost every weekend during the season. This past summer I took a two week vacation on the boat sailing.

I guess what I'm trying to say is if you use the engine a lot more than I do then it may make more of a difference when you change your oil. But certainly I would not worry about it this year.

dj

jssailem · Nov 29, 2019

@dlochner correctly identified the short cut (wrong term used - algae), I took regarding the nature of the contaminates in the diesel fuel we see.

Inside the Fuel Tank

Diesel fuel biodegrades easily. Given the presence of a small amount of water and exposure to bacteria and fungal spores—found in the fuel itself or, more rarely, introduced from the atmosphere —substantial amounts of biomass form amazingly fast. Only a trace of water is required, free or emulsified. Although true condensation inside a fuel tank is very limited under most circumstances, fuel almost inevitably absorbs small amounts of water.

DArcy · Nov 29, 2019

TimFromLI said:
Interesting article here on fuel tanks and condensation. Even so, I still try to fill it and use an additive- while the weather is still warm. Most important is making sure the O-ring at the deck fill cap is replaced when needed.

The Myth of Condensation in Fuel Tanks: Need a Full Fuel Tanks to Store or Lay-up Your Boat? - Boat Maintenance - by David Pascoe

Frequently we hear it said that the cause of water in fuel tanks is due to condensation. I have long doubted this assertion but the issue has come up so frequently that I was finally motivated to try prove to the point.

www.yachtsurvey.com

That is an interesting theory, but it is only a theory. For the past 20 years I have been designing electronics that operate on the outside of airplanes. We get extreme temperature and pressure variation which greatly exacerbate moisture problems due to condensation. Early in my career I was curious how much of a problem this really is so I placed a soda can in a thermal chamber and cycled it from +20°C to -55°C several times. After just a few cycles there was about an ounce of water in the can. Since then I have seen many designs which trap moisture due to condensation.

Boats, of course, don't see the same temperature extremes as jet aircraft but us Northerners do get changes from +40° to -40°C (in some places) which will cause some condensation over many cycles (years). I ended up with water in the tank on my C&C 27 which showed up after a boisterous sail in 50 knots of wind. It was likely building in the tank for years but just sat in the bottom of the tank until it was stirred up.

Having said all that, I'm sure a failed seal on the fuel filler cap will put water in your tank faster than condensation.

Barnacle Bill · Nov 29, 2019

To eliminate condensation you should "nearly" fill the diesel tank (leave some room for expansion). and it is a good idea to add a stabilizer as well.

SycloneDriver · Nov 29, 2019

I have maintained 18 diesel generators for the last 10 years. I take fuel samples & change the fuel filters every year. It can be very humid in Oklahoma. I have only had two issues with water in the fuel and I found a loose pipe fitting on top of one tank and a bad rubber grommet on the other. I also have a diesel truck and boat. I don't believe condensation is much of a problem.

As for fuel treatment additives, do your homework. Read the bottle. If it doesn't say something like "stabilizes for long term storage" it's not a stabilizer, I have the fuel sample results to prove this. The other techs at work swore by one particular product but even after repeated treatments my fuel samples failed the stability tests. I switched to a product that is specifically for storage and now my fuel sample results are fine. Use the correct product for the condition you are trying to treat.

It has been suggested by some of the local boaters that the winter additive is the one to use. Don't bother with a cold flow improver unless you operate your boat at less the 20 F. I don't use my boat when the water is solid, I doubt you do either.

SycloneDriver · Nov 29, 2019

DArcy - Islay Mist said:
Early in my career I was curious how much of a problem this really is so I placed a soda can in a thermal chamber and cycled it from +20°C to -55°C several times. After just a few cycles there was about an ounce of water in the can.

Wow. It's hard to argue with a test like that.
I don't find condensation to be much of a issue but your test clearly shows that it can be.

SycloneDriver · Nov 29, 2019

I would suggest that you postpone the fluid changes until next season.
I would also suggest that you start the engine briefly, run less than 5 seconds, several days before the scheduled launch. This gives you some time to sort things out before you put it in the water. You may wish to remove the impeller from the pump, but I personally wouldn't bother.

Davidasailor26 · Nov 29, 2019

Flammpz said:
Hi everybody.
Thank you very much. Great info here usefull for many of us.
Regarding the change of oil, the service was performed at the end of sailing season in 2017, then the whole 2018 was on land and now it has been used the sailing season of 2019. I believe is not very degraded due to use, but I guess it is degraded because of time. For sure I will change it in spring.

I am also thinking to do it while the boat is on land but it a big setup to prepare for the cooling...so I will see how I can prepare that.

I would also like to ask, what should I do when it comes the spring and I launch the boat to the water? Can I just start the engine after the winterization? assuming of course that all pipes are conected and so on...i mean the RV antifreezer will be just washout, right?
I am a bit worry that the engine will not start when the crame leave the boat in the water....

I’m also in the camp that I wouldn’t worry much about the oil change at this point. To do an effective change it’s best to have the engine up to operating temperature, and getting there on the hard isn’t easy. Yes it’s ideal to change in the fall so contaminants don’t sit in the engine all winter, but it shouldn’t be too big a deal. When re-commissioning in the spring yes you can pretty much just start up and go. Glycol based antifreeze will break down pretty quickly once discharged. If the yard used ethylene glycol (usually green) be sure not to discharge that on land as it’s quite toxic to mammals, but not really to aquatic life. Only other thing to confirm is that the seacock is open for the raw water before starting.

Don Crowther · Nov 30, 2019

One other thing that I do in the fall is fully charge my batteries. Then I disconnect them. If they are not fully charged they will freeze when the the tempature drops. You can remove them and and put them on a trickle charger for the winter.

In the spring a day or two before launch i take a 5gal. pail of water and put the intake hose in it. Then I start the engine and flush out the anti-freeze. If you had an unlimited supply of water you could run the engine long enough to warm the oil and then do a change.
This is just a couple of things that I do. Hope this helps.

thinwater · Nov 30, 2019

TimFromLI said:
Interesting article here on fuel tanks and condensation. Even so, I still try to fill it and use an additive- while the weather is still warm. Most important is making sure the O-ring at the deck fill cap is replaced when needed.

The Myth of Condensation in Fuel Tanks: Need a Full Fuel Tanks to Store or Lay-up Your Boat? - Boat Maintenance - by David Pascoe

Frequently we hear it said that the cause of water in fuel tanks is due to condensation. I have long doubted this assertion but the issue has come up so frequently that I was finally motivated to try prove to the point.

www.yachtsurvey.com

I really wish he would take that post down.

One of my jobs is API tank inspector (250-15,000,000 gallons). I've been in thousands. Condensation inside the roofs of diesel tanks is such a common problem and sufficiently damaging, that you are required, by code, to inspect the roof for soundness BEFORE you enter the tank. This is because rafters sometimes fall, and I have, in fact, found rafters on the bottoms of fuel tanks. The inside roof of the tank is commonly wet with water in the morning. It just depends on the climate.

Without going into the calulation errors, I will simply say that industry experience says different. It is true, the amount will be small, less than an ounce. Real water accumulation is nearly always the result of a leaky filler.

sailme88 · Nov 30, 2019

jssailem said:
Regarding fuel, it is a personal choice and depending on the age of the fuel, the source of the fuel, and your local conditions. I’d ask your local mates in the marina or a commercial fishing captain what he does. They would know.
I find that if you have any water in the fuel you will get algae growth. The addition of an additive will help to battle this. Also have fuel filters available for when you start the season.

With regards to oil changes I choose to do it in the fall so come spring I am ready to go. Unless I have complications then I do it in the spring. Fresh start to the season.

My oil is ALWAYS, ALWAYS ALWAYS changed in the fall.. This rids the contaminates and and moisture created by the engine heating and cooling. Needless to say the filter is also changed.

Winterization of Marine diesel tank and service of engine.

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SBO Weather and Forecasting Forum Jim & John

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SBO Weather and Forecasting Forum Jim & John

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