Bestevaer 49

[noelex]

Fuel filtration:

Feeding the engine with clean fuel is one one the most important things you can do for engine reliability.

There are three Racor 900 series filters. These are large filters for our sized boat, but if there is a problem with dirty fuel, large filters are valuable. For example the Racor 900 will filter over four times the amount of fuel than the slightly smaller Racor 500 series will before clogging.

I have seen boats with diesel bug problems that have needed to replace the primary filter every 15 mins of run time. Of course, it is much better to avoid these problems, but when cruising remote locations fuel quality may be poor. Large filters help buy you time and options if you inadvertently pick up dirty or water contaminated fuel.

One of the three filters is dedicated to the polishing system with a pickup at the very bottom of the tank. The second filter normally functions to filter the fuel before it enters the day tank, but if there is a problem with the day tank the engine can be fed directly from this filter. The third filter further filters the fuel from the day tank, which is then fed to the engine.

So for normal engine operation, which is via the day tank, the fuel has been filtered twice, even ignoring the polishing system, before it enters the engine and the normal secondary engine filter.

This photo shows two of the filters. These are mounted under the aluminium anodised workbench in the workshop/technical area.

[npf1]

Not tempted by glass bowls, so you can see the build up of crud?

[NormanS]

Presumably the main tanks are part of the hull, so they can't have sumps and drains, by far the best defence against water and dirt?

[prv]

Presumably the main tanks are part of the hull, so they can't have sumps and drains, by far the best defence against water and dirt?

They can still have drains, in the form of a dip tube to the very lowest point. If they're at the bottom of the hull then they can't have sumps, of course, without a strange appendage below the boat

Any plans for vacuum gauges to show how clogged the filters currently are?

I see you have jubilee clips on the hoses. So do I, but after I'd finished building the system I wondered if I should have gone for those ear crimps instead.

Pete

[Dave100456]

Noelex
Thanks for posting. Great info on solar systems.
Dave

[Ric]

Any plans for vacuum gauges to show how clogged the filters currently are?

My first though too - surely if you are going to the trouble of fitting a system like that you should also fit a vacuum gauge so that you can see what is going on and potentially switch out a clogged filter before the fuel flow stops?

[noelex]

Not tempted by glass bowls, so you can see the build up of crud?

Yes a good point it was a tough choice but in the end I went for the all metal filters. This is the reasoning.

The Racor turbine series of filters are available with three different types of bowls: a clear plastic bowl, a clear plastic bowl with a metal shield around the lowest part, (the metal shield increases the time before the the plastic bowl melts if there is fire) and the version shown here with an all metal bowl.

The plastic bowl enables any water accumulating in the lower part of the filter to be seen without draining a sample from the bottom tap. It is a great feature. We had the plastic bowl version of the Racor 900 filters on our old boat and it is very reasuring to see nice fuel in the bottom of the filter. It is something I will miss, although we never detected any water in the fuel in 10 years.

However, as with every equipment decision, there are pro and cons. The plastic bowl does occasionally crack, mostly if the filter is accidentally knocked, but they seem to become a bit more brittle with age. You also have to be careful with the torque of the bolts when the filter is resembled after a thorough cleaning.

Problems are not common, but with the aim of installing the most durable, fuss free, and dependable fuel system, the rigid and durable all metal bowl has some advantages. The filter can take a beating and the all metal bowl is safest if there is a fire. The assembly of the metal bowl is less critical. The bolts holding the lower bowl in place can be tightened to ensure an air tight seal (diesel has an incredible ability to find the tiniest gap) without a risk of cracking the plastic bowl.

The drawback of the metal bowl is convenience. To check the fuel you need to loosen the nut at the bottom and collect a sample. While this is more trouble than looking through a clear bowl it has the advantage if you decant into a clear glass jar that you can more easily see small amounts of water and contamination and also better judge the clarity of the fuel, which can be hard to see when through the thick, curved, tinted plastic bowl.

To offset this inconvenience the filters in the new boat are very easy to access. They are mounted in the technical area/workshop rather than the engine bay. So taking a sample should be as easy and quick as checking the engine oil.

The polishing filter takes fuel from the very bottom of the tank and filters much more fuel. Perhaps a hundred times the amount of fuel the other filters process, so this filter will show problems well before any of the others. If there is no water and crud in this filter it is hard to imagine a mechanism that would cause the other filters to be worse. Normally this would be the only filter that needs checking. The polishing sytem is seperate from the engine supply so if any air is introduced when the fuel sample is collected it cannot effect the main running of the engine. The all metal bowls mean I dont need to be concerned about knocking the filter or something falling against the filter and breaking the bowl.

Even with the plastic bowl models I still took a fuel sample from the bottom of the filter once a month to better check for the earliest sign of a problem, so I don't think a weekly, or even daily fuel sample will be much extra work, given the filters are so easy to access. Time will tell if this was the right decision.

[noelex]

Presumably the main tanks are part of the hull, so they can't have sumps and drains, by far the best defence against water and dirt?

Yes, you are correct. With a tank that is integral with the the hull a sump is hard to fit, although in some designs part of the keel can be used.

There is a polishing system pick up from the very bottom of the tank, which partially makes up for the lack of a sump. and under normal operation the engine is only fed from the day tank.

The day tank has a very large sump area with a valve and drain. Because it is mounted higher (so the day tank can gravity feed the engine even if the engine lift pump fails) the sump is very easy to access and drain. However, it is unlikely the day tank will pick up water and crud as all the fuel that enters this tank has already been filtered from the main tanks by one Racor filter.

There is another Racor filter between the day tank and the engine, so normally the fuel passes through two "primary" filters before entering the engine. If there is a problem with one filter, or with the day tank itself, the fuel can be fed via one filter direct from one of the main tanks.

[westhinder]

This thread is a fascinating read. Thanks for sharing your insights and giving us food for thought.

[noelex]

Thanks for all the nice comments.

The galley bench-tops have just been fitted. My wife is a keen cook so the galley is an important part of the boat.

The brushed stainless steel bench-tops are surrounded on all sides by a welded raised square profile lip. This contains minor spills and removes the need for a sealant around the edge which invariably becomes mouldy with time.

The central bench-top has an integral handrail along its length which follows the curve of the rear section and has been beautifully finished by KM.

Much of the surface has been covered up for protection while the rest of the interior is completed, but here is a sneak peak.