Fuel for thought

Diesel engines are generally extremely reliable. In a fully mechanically injected engine it will run even with a complete loss of power, you might not even be able to turn it off with the kill button.

This is a good thing on boats, even more so on sailboats where rarely is there redundancy with the luxury of more than one engine. My skill level in sailing would prohibit me in entering any of the marinas we have visited  without an engine, even losing the bowthruster is a concern. 

With a ship of 25 tons, it is wellbeyond anyones physical power to use muscles or body parts to stop its motion. 

The B57 sports placement of the propeller at some distance from the rudder resulting in no help from propeller wash at low speed. You learn pretty fast that if you dont take into account propeller effect in reverse it is going to work against you, hence you also need to have a few knots to have control. In situations like these you rely entirely on that the engine is capable of slowing and stopping the ship. 

Hence, you need to trust you engine. This means to be sure the fuel is clean.

Artemis has two filters. One is right on the engine and part of the injection system. It is the last in line to make sure the fuel is squeaky clean before it enters any of the four injectors.

The filter before this is larger and of the Racor FG500 type. A very common filter. 

It is a really good filter that also separates water from the fuel. The particle filtration is carried out via a disposable cartridge. It is available in several grades, normal 30mikron down to 2 mikron. 

Replacement is very simple, unscrew the T-handle and lift of the top. Grip the plastic ring around the filter and lift it out. Place the new filter, check the O-ring on the lid (or change it) and put the lid back on. Strictly speaking you do not need even have to refill the filter housing unless the level is lower than around 25mm below the edge. If you do, make sure the fuel is clean.

As you can´s see this filter cartridge you wont be able to see if there is anything that can block it. You can see water in the transparent bowl and draining it is also easy. 

As Artemis has three fuel tanks and they do get rotated (at least two of them) fuel is circulated everytime the engine runs. Part of the fuel is returned to the tanks by the small hoses attached to the injectors. So in a way the fuel is polished. I always add the correct amount of fuel biocide when filling up, still water may enter through condensation as the tanks must be vented. It is more of a fact that there will be water sitting at the bottom at some point.  If this begins to grow it creates a slimy sludge the quickly clogs any filter. 

So even if the fuel itself is filtered and returned to the tanks, there might be something living at the bottom. This will appear when you least need it to, according to certain laws.  The junk can be so bad it actually clogs the fuel line and will stop the show. However if it makes its way to the FG500 filter it may be spotted if you happen to be in the engine room often enough. 

What I dont want to happen is that the engine quits when it shouldn´t. But if it does I want to be able to get it going as fast as possible. So I decided to build a dual filter unit with valves that allow for rapid switchover. An additional item added is a vacuum gauge tied in on the outgoing line. If the fuel pump has to work hard to supply the engine with fuel it may be due to a filter becoming clogged. This will then show up on the gauge as an increase above normal and you then get early warning. The dual filter will also allow cartridge and drainage of water without shutting of the engine. 

I bought two Chinese FG500 rip-offs as I took a chance on the quality and it turned out ok. Then I bought regular 12mm water fittings common in all of Europe. They are actually approved for gas as well. The tubes are as you can see in copper and the ball valves are in stainless. The T-couplings and adaptors I could not source in stainless and are nickelplated brass. First I did a test setup on a piece of wood to figure out the best placement and tube bending.  

I opted to use crimping hose clamps, the too in stainless. All the tube end have a small collar soldered onto it to ensure the hoses cannot slide off. The collar you buy as extras and are for the conical tube connections. Turned out really well. The vacuum gauge I also sourced online from Germany selling the wllknown brand of Wika 

When all the tubes have been bent and it all seemed to fit cut and welded 20mm square steel tube and 30mm L profiles to create a robust frame. If used what I had at home and departed from my rule of never put mild steel on the boat. But...it is in the engine room and it was painted with Hammerite. The end result looks like this; 

Installation involved a process of minimizing diesel spillage in the engine room. This is a battle
that cant be won so it is a bit messy. 

The only miscalculculation done was that I was under the impression that the fuel line where 10mm. Turns out they where 8mm. The ships box of brass goodies only allowed to build a single unit to go from one size to the other, this was attached to the inlet. 

A visit to the local "ferramente" yielded a couple of brass hose barbs in 10mm only. I also got an Espresso on standing foot. They also had a Y split. Took two of those. With help of the marina staff I got driven to a local machine shop with a lathe that reduced the hose barb to a little above 8mm.

Y splitter ready with check-valves and 10 to 8mm reductions.

Due to in part limited space I also decided to split the output of the filter pack for engine and genset. Normally this is not advised as practise is to not allow extended use of the generator to empty a tank. 

However, Artemis has three fuel tanks and if the Captain lets a situation like this occur he will learn the hard way to not repeat it. 

Lucky I was to also identify a small leak on the hose to the generator, right where the hose bends most by the filter outlet. This prompted me to also change and better route fuel hose to the engine.

Next to the filters was located the engine room bilge pump, moving it a little bit aft allowed for a neater installation of the filter pack.  

After filling the FG500 type filter with clean diesel from the top the next step was to get the air out of the hoses to the engines. On the main engine this is very easy, which is not always the case on marine engines, all you need to do is crack a screw open on the engine filter housing and push on the pump until only fuel exists the screw. 

On the genset it turned out to not work so well. Could not get any fuel up to the engine until I discovered I had attached the fuel line from the tank to the filter group, thinking it was the input to the generator...

With the corect hose in the correct place all was then operational.

All in all, very pleased.