160: Marine Diesel Fuel System - Tank Contamination, Corrosion Comprehensive Cause and Effect

Oh, man, I definitely need to get this on film. I cannot believe it. Babe, when was the last time you brushed your teeth? I can't believe you're brushing your teeth right now. I'm getting this on video. Hey, my mirror's broken. How do they look? Yeah, I brush them every week or so whether I need to or not. Who needs the dentist? These are pretty teeth. Hey, Blindaway viewers, subscribers, and Patreon supporters. Thanks for tuning in. Oh, that little skit? I'll show you how that ties in a little bit later. Today's video is about a much misunderstood and seldom talked about fuel tank corrosion causes and preventative measures. Much more importantly, preventative measures. So this video is gonna be a little different from things in the past. It's gonna be more like a visual informative podcast. Also, please note that this is a non-sponsored video, so there are no influences in the background. What we think is truly our opinion. Why are we doing this? Eileen and I have been so moved by the profound disruption and the extra cost of having our leaky fuel tanks diagnosed, which we did it ourselves, and then removed and fixed. We do not want this to ever happen to us again, and especially we don't want it to happen to you. So that's why we're going through all this trouble to research and do this video with the hopes that it's gonna help you in the future. Here's why we do these videos. I'm drawing on my experience as a teacher, also as a boater having dealt with this type of issue, and having worked in Texas in the diesel fuel industry. Also, I want to tell you if you're one of these boat owners that has these newer plastic polyethylene tanks, don't think that you're immune to the contamination issues, because it could happen to you also. So even though your tanks aren't made of metal, you need to listen very closely to what we're talking about here, so it doesn't happen to you. If you find informative videos like this helpful and help you save money and make your life as a boater easier, please subscribe, hit that like button, and comment. We want to hear from you, and make sure you share it with other boaters, because pretty much everybody's going to be in need of this information. And we really appreciate our Patreon supporters, and they help us stay out here doing what we're doing. Okay you all, let's get started. Just to recap, our first in a series of three videos on fuel tanks focused on how we figured out we had a problem and how we search for a solution. The second delves into how we fix the problem, and now with this third we'll teach you about diesel fuel tank health corrosion causes, and most importantly ongoing preventive maintenance. So make sure that you stay tuned until the end, because this one's really important. Also, if you have or are thinking about buying a boat with metal tanks, and there are plenty of them out there, trust me, this video is a must. And if yours has some of the newer plastic tanks, don't be thinking you're now a superhero, because you're still vulnerable to potentially dangerous fuel contamination issues, which could significantly affect the health and safety of your boat. I'll explain later. There are almost no YouTube videos on this most important issue of marine diesel fuel tank health, because the issues are so hidden in the tank, and involve some harder to understand concepts. Have you ever heard the expression, out of sight out of mind? Just because you don't see them, doesn't mean there's not a destructive party going on inside of your tank. Not only is it now personal, because it's happened to Eileen and me, but it's also been painful, disruptive, and expensive, and fortunately preventable. To top it off, and to add some additional credibility, I'll draw on my expertise working in Texas, helping diesel fuel dealers and farmer co-ops solve problematic issues dispensing fuel from their diesel fuel tanks. Guys, it's time to go to school, and I just want to warn you, we're opening up a huge rabbit hole here, and can't possibly cover everything. So we encourage you to leave comments, ask questions for us to answer, and possibly include in a future video. Okay, let's get started. In an attempt to understand marine diesel fuel tanks health and prevention, we will focus on the following topics. Number one, causes of corrosion. Number two, prevention. Make sure you stay tuned, because this is by far the most important part. Warning, before we get started, I want to reiterate that even a small drip from your fuel tank is a serious issue that needs to be fixed. It's only going to get worse, and in all likelihood, develop into a steady stream of diesel filling your bilge, potentially after hitting a big wave under passage. So don't let this happen to you. Our first topic is causes of corrosion, and to better digest it, we'll break it down into the following subtopics. Number one, short-term thinking. Number two, enemy number one. Wow, that's an interesting, I want to know which one that is. Number three, microbially induced corrosion, otherwise known as MIC. And to better explain this, I'm going to use a tooth decay analogy, which I think everybody's going to understand. Then we're going to talk about algae myth. And a myth, remember, that's something that's been told so many times that everybody believes it, but it's actually not true. And the last two MIC subtopics are the fuel polishing myth. What is it, and how is it false? And lastly, we will discuss biocides, which are much misunderstood, along with the biocide myth. And because I've given you a firm foundation in the life cycle of microbially induced corrosion, what I say will make perfect sense. And four, galvanic corrosion. Remember in high school chemistry, when you studied the exchange of electrons? We're going to revisit that to achieve full understanding of the damage being done to your tanks. Blown away was a charter boat based at mooring Sunsail Grenada for five years, where there is hot, humid, tropical weather, and a long rainy season. From what I've heard from ex-charter company technicians, who have now started their own private boat repair companies, that other than getting the toilets unclogged and changing the oil and fuel and oil filters, there was little care or understanding regarding tank maintenance. The big emphasis was keeping our Leopard 44 rented to bare boat customers paying eight to twelve thousand dollars a week. And hey, they're selling the boat after five years and as long as the engine works, why bother with the understanding of corrosion and checking the tanks, right? But if you have the long-term thinking of the conscientious private owner, yep, that's you, you'll be much more proactive and preventative, which we'll get to shortly. Okay, let's start with the big one. What is hidden will hurt you. Water is our enemy number one and it's everywhere. Most importantly, water and salt and seawater are electrolytes and most significantly contribute to the corrosion process. We'll talk more about that later. Let's make no mistake about it. Water is by far the biggest problem and without it, there are little to no problems. So how is this? Let's learn more. There are many ways that water enters your fuel tank and this is one of the reasons why it's such a big problem. Let's go over the main offenders. But first we need to know more about the following diesel fuel characteristics. First and foremost, diesel is highly hygroscopic. That means that diesel has the ability to attract and hold water from the environment. So if there is any water in the environment, it's going to attract it like a magnet. This is one of the reasons why your diesel engines have both a primary centrifuge racor type filter and a secondary fuel filter to protect your engine's precise fuel injectors that must have fuel clean of water and particle contaminants. And to top it all, diesel fuel naturally has 60 to 100 parts per million of water dissolved in solution before it falls out of solution and becomes a problem in your tank. And check out this cross section of the typical fuel dealer's storage tank to better understand what's going on. Also, imagine it being your boat's fuel tank as the same principles we are about to discuss will apply. Notice the vent at the top which is similar to your boat's fuel tank. Fuel will expand and contract as the ambient temperature changes. This causes the fuel in your tank to push air out of the tank in periods of expansion and to draw humid air in during periods of contraction. This breathing of the tank draws air into the tank that contains moisture and that can form into water droplets and accumulate in the bottom of your fuel tank. And the more condensation is produced if your tanks are partially full. Notice the sludge and bacteria at the bottom. Yuck! We'll talk about them in a bit. Then another big offender is your boat's fuel filler cap. It's a big culprit. Leaking filler cap, a bad gasket, and also filling while it's raining or just leaving it off. I mean if you don't care or you get distracted that's going to happen, especially if you've got a charter guest and a quick turnaround and it's raining you still got to put the fuel in, right? Another way for water to get into your fuel is a result of one of the unique characteristics of your diesel engine. The green line shows fuel being pulled from the tank to the fuel pump becoming the high pressure red line feeding the fuel injection system where it's heated to about 100 degrees celsius and then the unused fuel returns to the fuel tank through the yellow line. This recirculation process brings the hot diesel into the cooling tank causing even more condensation and unfortunately, this cannot be prevented. Water can also be introduced into the fuel during transportation. After the fuel is refined it is often passed through multiple tanks and trailers before reaching its final destination. Many of these tanks hold the potential to have accumulated condensation and contaminants of their own. Also let's don't forget about those five gallon jerry cans you use to transport fuel in. They're disgusting and the only way to clean them out is with water. Be careful that none remains when you put them to use. All right, y'all let's get around to the big one and that is causes of corrosion. As a base for future knowledge learned on this video before we can talk about anything else, it's essential that we learn about microbially induced corrosion otherwise known as MIC. Note that there are a lot of misunderstandings in the cruising communities. Pay close attention and focus on this Biofilms 101 diagram that shows the life cycle of these plantonic bacterial microbes as I break each stage down and discuss in detail. After this I'm going to talk about why you go to the dentist and what do they do to your teeth? Because it's a close to home analogy of MIC formation and what happens to your fuel tanks. In your mouth you end up with cavities and in your fuel tanks pitting corrosion. Please feel free at any time to pause your video player. Okay, here we are at stage one attachment. We have microbes everywhere. Yes, that's the bacteria and they exist in the fuel water and on the tank lining and they're feeding on the water and the hydrocarbons in the fuel. They're floating around. Plantonic means floating. These bacteria are seeking surfaces to attach themselves to similar to barnacles on the outside of your hole. We all know what that's about. This next stage two is about biofilm growth and I mean it's growing everywhere and it's very similar to the plaque and tartar growing on your teeth and there are a lot of scientific terms which I'm going to gloss over. Remember that rabbit hole I was talking about? This is a cute little bunny, but we're not going to chase it. Note the biofilm will grow anywhere the fuel touches like the tank floor, the walls, the fuel center, fuel lines, hoses and fuel filters just to name a few. And if you're one of those that has those plastic polyethylene tanks, you're not immune to this and the following stages we're about to discuss. Welcome to stage three where the biofilm, which is the microbes home, grows into a complex three-dimensional structure and the pH becomes more acidic due to the bacterial waste which if left untreated will cause pitting corrosion resulting in a dreaded leak. In stage four we learn about biofilm properties which are a necessity for full understanding like soldiers in a reinforced concrete bunker. The bacteria in their hardened homes are extremely resistant to attack and this includes biocides which are much misunderstood. Ever wonder why you have to keep reapplying biocide? Well, I guess now's a great time to talk about the biocide myth, which is quote, when I use biocide, it's going to kill all of the bacteria in my tanks, unquote. And yes, it's going to kill a lot. However, because it never reaches those microbes entrenched deep within the biofilm. Yes, it's a matter of time before they come back and now they have dead bacteria to feed off of. Also, have you ever checked your Yanmar engine manual to see what it says about biocides? Here's mine and it prohibits the use of biocides and I'm sure they have good reasons for it. In addition, the bacterial microbes build up a resistance similar to human bacteria and antibiotics. So for them to continue to kill you'll have to start alternating different types of biocides so they will continue to be able to be effective. If that's not enough of a reason to stop using them they are highly toxic and that could produce a safety hazard. Now's a good time to introduce stage five, sloughing bacteria, but we're also going to finish up on biocides. These sloughing dead bacteria have the potential to plug your filters affecting engine performance at the roughest point in your passage when wave action lifts the dead carcasses off the bottom of your tank while doing nothing to address the problem of the water that is in your fuel tank. Here the bacteria are having a huge out-of-control destructive party rapidly reproducing and sloughing off in the slimy strands giving this bacteria the nickname slime forming bacteria, or you may have heard it be called the diesel bug. It's clouding the fuel and if left uncontrolled can contaminate the entire fuel system including filters, pumps, injectors, and fuel lines. To make matters worse the acidic waste byproducts of the bacteria stuck to your metal tanks in the biofilm develop anodic sites which lead to pitting making your tank floor and walls sacrificial just like the zincs on your cell drives. More about that later. Okay, it's time to prove or debunk the algae myth as false. You've probably called slime forming bacteria in your tank algae from time to time. A major company even named their fuel polishing machines after it and by a side to go ahead and admit it you used it haven't you? Guys, algae are plants. It requires photosynthesis to live and grow and it's mostly beneficial. But let me tell you there is nothing good about this slime forming bacteria microbe as it grows and spreads throughout your fuel system. Myth debunked. Okay, let's move on. Okay after MIC the next form of corrosion we're going to explain is galvanic corrosion and in the end we're going to show you how they are both tied together. Galvanic corrosion refers to a corrosion damage that occurs when two dissimilar metals are in electrical contact with an electrolyte where the more noble metal is protected and the more active metal tends to corrode. One reason why corrosion is so prevalent in boats is because they are surrounded by an abundance of salt and water. Both electrolytes. With regards to your fuel tanks galvanic corrosion could be even caused by a loose aluminum screw and in contact with your aluminum fuel tank. Ever wonder why your boat prop have sacrificial zincs as an anode? With your sail drives in the water all the time corrosion is unavoidable. So the engineers specified attached zinc anodes are cheap and easy to replace. Take a look at this galvanic metal ratings chart and learn how the metals are related. Which metals are more noble or cathodic which means they are far less likely to share electrons along with the least noble or anodic metals more likely to be sacrificial and share electrons. Ever wonder why people spend a bundle on copper rain gutters? Check out this chart and you'll see why. Now here is where a microbiological induced corrosion or MIC intersect with the cathodes and the anodes. The real danger of bacterial biofilm is that the microbial waste is acidic which contacts the metal tank causing it to become an anode and sacrifice electrons which accelerate the pitting corrosion causing the dreaded leaks in your tank. Which makes me want to ask all of you an off the wall question. Why do you take the time and money to see a dentist once or twice a year? To have your teeth cleaned of biofilm called plaque and tartar. Oh, that's just downright nasty. Caused by bacteria in your mouth which feed on food particles and water and excrete acids causing tooth decay very similar to what's happening in your tanks. Unfortunately fuel tanks are not as accessible as teeth to diagnose and clean. I hope this real life analogy helps you better understand the damage that's happening and what needs to be done to prevent problems from occurring in the future. Stay tuned where we discuss the most important corrosion prevention methods. Wow, that was a ton of information that you all just took in. So what I've decided instead of just having you drink from a bigger fire hose is to stop right there and then next week we're going to start afresh and continue with the prevention to keep this from happening to your tanks moving forward. So essentially what we just discussed is part one of a two-part series of our third of a three-part series. Does that make sense? It's a little crazy. I hope it does. We'll see you next week and make sure that you leave comments down below if you have any questions on this week's series.