Clean Tanks A Key To Smooth Running
Professional Skipper Magazine Issue 44 Mar/Apr 2005 (unedited)
Carrying on from where we left off, making things simple or easy to get at. The other day I was on a vessel to carry out some oil samples from both the engines and transmissions. As I normally do I took a look at the fuel filter sight glasses. I was stunned to see that both the Port and Starboard filters had what looked like trees growing in them. Both were jam packed with Microbiological growth (Diesel Bug).On questioning the skipper I found out that he was having to change over from one bank of filters to the stand-by set every 25 hrs or so. He then changed the blocked ones when he got back to the dock. He told me that when he took on fuel he always dosed the fuel with a biocide product and that unfortunately he was stuck with this routine until the season come to a close.
Once winter came the vessel was in for a refit. Part of the overhaul was to open up what they could of the fuel system and clean it. Looking at how heavy the Diesel Bug infection was that would mean removing the maze of fuel lines and opening the tanks up.
The biggest problem was that while they could get at a couple of the tanks very easy the rest were down right difficult, if not impossible to get at. Their main problem being that they not only needed to get to the tanks, but they also needed to cut them open and where possible put inspection ports in them. This would enable them to thoroughly clean the tanks out now and if needed inspect them at a later date.
Cleaning the tanks out completely was the only way that they could guarantee to maintain clean filters. Unfortunately when it comes to Diesel Bug dead bugs are as bad as live ones, if not worse. While a good Biocide will kill off an infection it will not remove it from the tank. Thus here in lies one of the problems. Is the growth in the filter sight glasses dead or alive? Unfortunately for the vessel operator it doesn't really matter, as both will block the filters.
The only way to tell is with microbiological testing. This type of testing will tell you at what stage the infection is at and if your treatment process is working (if you have one). Also note that if a treatment or dosing programme is allowed to lapse the infection can reoccur quite quickly. This is what I believed occurred while the skipper was away from the vessel.
Going back to the vessel I was working on, the intention was to have the boat builder do some major upgrades to the interior of the vessel. However, this work may now also include access ways or hatches to be cut into the interior so as to gain entry to all of the tanks. Unfortunately if any remain unclean then the job will have been in vain.
This is because re-infection can take place very easily if an unclean tank is left to operate in the system. Once the tanks and lines are cleaned then a treatment process can be put in place with the reassurance that they will stay clean.
There are a couple of treatment products available on today's market, however the one I can recommend, if you are starting afresh with clean tanks is the Fuel Mag product. This simple device will allow you to get on with what you do best, that's work the vessel in a safe operational manner without having to continually purchase and add additional products to your fuel.
You may remember back to my first article in which I told you about a vessel that had major fuel dilution problems which turned out to be the end result of a heavy microbiological infection.
In the case of this vessel we were able to get at and clean the bottom of all the tanks very easily. This was because all the tanks had very large inspection covers and all were accessible.
The six tanks were all located together in the same area and to my relief right next to the large beer and bait fridges. With the tanks only being half full it meant that we were able to push the fuel via a filter pump set-up into three of the tanks while we got on cleaning the others.
Just as a side issue, what we found was that a good percentage of the bug was stuck to the bottom of the tank. If we had not pushed it we would not have been able to move it.
However, while the amount of bolts we had to remove and put back did our heads in, at least we were able to gain access to all the tanks and thoroughly clean them out, thus the only headache caused was by the amount of piss we drunk afterwards.
I can not reiterate strongly enough, especially to those of you who are having new vessels built, make sure you have good uninterrupted access to the bottom of your fuel tanks! It saves so much hassle in the future particularly when it comes to dealing with these types of issues.
One last thing, low points, stripping or drain lines and valves. These to can add to the quality management of your fuel system. Where possible all vessels should have fitted good access points to allow for the fuel or in some cases water to be drawn off from the bottom of the tanks, thus helping to control the microbiological headaches.
Good sailing
Written By Kelvin Hieatt
Managing Director Marine Diagnostics Ltd
