ETERNAUT Fuel System
It is just amazing how many faults this boat had when it arrived. It is said that every new built yacht has problems… but this bad?
Anyway, one of the major tasks over the last weeks has been to get the fuel system in order. Major work is done. Minor jobs on the fuel system are still lying ahead, but those are not urgent.
Below are the different components of ETERNAUT’s fuel system explained.
Fuel Filler
The main fuel filler is located on the fore deck. That fuel filler has a commercial fitting. It allows me to use the same huge refueling hoses that super yachts and ships use.
A second, regular sized, fuel filler is at the stern. Only the stern tank can be refueled from there.
Commercial fuel filler located on the fore deck.
For the recent work I needed to remove fuel by hand pump from the stern tank and add it up to one of the underfloor tanks through this fitting.
While doing so I discovered that Seahorse Marine did not use Diesel resistant paint for the filler.
Not a smart move from the shipyard and another item on my never ending to-do-list.
Fuel fill valves
From the main fuel filler the diesel falls straight down through a pipe passing the galley area. The main inlet valves for the underfloor tanks are located underneath the galley.
Through the different valves all 5 underfloor tanks can be selected independently.
Fuel fill valves
Either of the five underfloor tanks can be selected through these valves.
As we have found out during the first Sea Trial all of those five fittings are leaking slightly. Not much and so far an old towel has been enough to stop the diesel flowing around.
But over time I want to tighten those fittings – which requires a huge 2 1/2″ spanner.
Fuel Tanks
Underfloor Tanks (others than day tank)
In total there are five underfloor tanks. One of them is the day tank. The day tank I will explain in the next paragraph.
The other four underfloor tanks have a total capacity of 4,500ltr. These are the main tanks for storage. Each one has it’s own maintenance hatch. All hatches are equipped with two fuel capacity sensors: One electronic for the indication in the cockpit and one manual gauge for backup. The respective gaskets of the hatches I had changed to NBR (Nitrile – Buna-N Rubber) with a dressing of Permatex Form-A-Gasket No2 (non-hardening) a few weeks before.
Day Tank
The day tank is one of the five underfloor tanks, but it deserves it’s own paragraph. That is due to it’s importance in the fuel supply system. Volume is 1,220ltr, which equals around 80 hours engine time.
Engine, Generator, Diesel Heater… all users are fed directly from this tank. The users cannot be fed from any other tank!
Unfortunately the maintenance hatch and backup mechanical fuel fill indicator are below the staircase. To get access to the tank the stairs including the lights for the steps have to be removed. It’s location is very inconvenient as the backup gauge is not directly in view! Why has Seahorse Marine done it this way? Who knows. Another “no-have-brain” at work…
Inside the Day Tank
When checking the fuel for construction debris I also took note of the different suction hoses for users.
Note that the engine had the lowest fuel take off point: in the sump. That is the spot where the last drops of fuel accumulate. But that’s also the place where the dirt and water gather – all that nasty stuff you do not want to contaminate your engine with.
The suction point I had marked “purifier” actually feeds into the fuel manifold. The purifier is fed through the fuel manifold and has the largest diameter supply hose. out of this tank.
GenSet and Heater pick up points are somewhat low, but at least not in the sump.
For the first few days I disconnected the “purifier” hose from the fuel manifold and connected the engine feed instead. Then I used the engine feed line to clean the fuel (and tank) through the purifier. That way I ensured that the dirt from the sump ended up in the purifier and not in the engine fuel filter.
After several hours (days) of cleaning I swapped the hoses. Now:
- “Purifier” pickup feeds into fuel manifold
- “Engine” pickup feeds the generator
- “Generator” pickup feeds the engine
I won’t be able to use the last drop of diesel for the engine anymore. But should dirt and water be in the tank it clogs generator filter and not the engine fuel filter!
Why I did not just swap engine with purifier supply hoses? The supply for manifold and purifier is larger diameter copper tubing and runs straight into the manifold. The larger diameter allows higher fuel flow through the purifier which is recommended to have it working properly. A perfect setup would have required to cut the tank open and insert a large diameter copper tube into the sump to feed the purifier. But that’s well beyond my scope of expertise at this stage.
Stern Tank
This is the largest of all tanks. It can hold 1,900ltr. I do not know whether I will ever use it except when absolutely necessary for the range required.
It sits in the very far aft of the boat. I can imagine that this amount of weight that far back might negatively affect center of gravity of the yacht. Not that the boat will tip over… I expect more something like high blood pressure in the head when sleeping 😉
Last week’s task had been replacing the gaskets and level gauge of the stern tank. It had been a long and daunting task. I think my whole life I have never used as many swear words as when we tried to get the stern tank into order.
A note to my wife: Thank you so much for your effort and determination.
For anyone who knows me: I admit that I can be stubborn and determent. For those who do not know Rita: find the superlative.
A note to Seahorse Marine: Your shit work puts an enormous stress to any relationship!!!
Let me start from the beginning:
Removing old gaskets
Every day work at the stern tank started with removing blankets, pillows, mattresses and wooden bed frame. As storage on a boat is prime area it all piled up on one side of the bed while working below the other side at the stern tank.
The screws of the stern tank hatches required a 30mm spanner / 30mm nut on wrench. Of course out of range for my (although already extensive) tool boxes. Mong Kok… here I came again for shopping.
Removing old fuel level gauge
Bending over the stern compartment, far down below, a torch revealed: somehow the bolts and gaskets of the attachments for the fuel level gauge looked weird.
Rita and I took turns: The steel support for hydraulic steering and rudder stem did not leave much space for us to work in.
First we had to take a look and remember any distinctive feature we thought being able to remember by touch. Then we had to crawl forward while bending the upper body downwards through an opening of the wooden bed support. One arm had to support the body weight, the other arm with hand and tool had to squeeze through a 15cm gap. One finger of the hand with the toll had to find the bolt by touch…
Most important helper
…oh, dropped a tool? Climb out again, locate the tool in the bilge far down below, grab the 90cm extension arm, get the tool out… and start over again
It took two days until we had all old gaskets removed.
Especially nasty was the lower holder of the fuel level glass. That gasket was completely deformed and it would have leaked. Additionally the shipyard had broken the glass close to the upper holder. Diesel leakage guaranteed.
Another visit to Mong Kok
To get new gaskets another visit to Mong Kog was due. I knew the address:
Hoi Luen Hardware, Dundas Street 23
The owner speaks good English and gives advice which sort of gasket material to use.
Other streets close by offer a good range of tool and hardware shops.
But each shop is small and deals with it’s own niche products. Shopping in Mong Kok takes time!
Installing new gaskets and visual fuel liquid glass
When you think removing everything was tedious… imagine re-installing. It took days and came closest to relationship stress limit than any previous event our life.
“Dear marriage counselors: Send us your patients, the repair work on our boat will give their relationship a new meaning!”
SeAHORSE MARINE BOAT OWNER
Fuel Purifier Alfa Laval MIB303
After a couple of failed attempts I was getting the fuel purifier running.
Having a couple fuel tanks and being able to select between the amounts carried in each is good as it gives you the ability to balance the boat as you wish. It also enables me to run the Alfa Laval MIB303 fuel purifier to clean that fuel which just had been refilled… who knows what quality it is and how much water it contains.
Purifier vs clarifier mode
The Alfa Laval MIB303 can be set up as purifier or as clarifier: In purifying mode it separates mainly water-, in clarifying mode it separates mainly dirt from the fuel.
My unit had been delivered set up as purifier. As I suspected a lot of construction debris in my tanks my intention was to have it run as clarifier first.
But: Seahorse Marine had misplaced my conversion kit and the required tool set. I had to order new and await delivery for replacement.
After I had changed to the clarifier kit the Alfa Laval dropped heaps of fuel into the drip pan below.
As per manual I had checked all hoses for possible blockage. There was no fault. Then dismantled the purifier piece by piece. By cross checking/comparing the unit with spare catalogue list I found the lower O-ring missing. Swapping the O-ring from purifier to clarifier bottom was not mentioned in the manual.
To be able to clean all debris out of the day tank I had swapped fuel supply hoses of engine and purifier (manifold). Only this way I ensured that the fuel tank sump is cleaned as well.
After running for a couple hours I checked the dome of the purifier: some dirt had been collected and a few water drops appeared in the run off. You should have seen my happy face when I figured that the purifier is doing it’s job.
Dome of Alfa Laval MIB303
After removing the dome of the Alfa Laval purifier / clarifier the remaining fuel runs off into the collecting tray. There you can check for water traces in the fuel.
The dirt and smudge collects in the dome. The brown stuff here are probably fine rust particles out of the tanks and first traces of smudge… the sticky remains of bacteria growing in a small layer where water and fuel meet.
Fuel Manifold
The fuel manifold allows me to transfer fuel between the different tanks by a fuel transfer pump.
Also it allows me to select any tank to feed the fuel purifier.
Seahorse marine had not labelled it correctly. That was the cause for the nasty fuel leak in the engine room a few weeks ago when I cleaned the tanks through the purifier.
Correct and wrong
The shipyard has sent new labels for the fuel manifold. New correct labels on top of the old wrong ones
Fuel filters
In addition to the mounted fuel filters of engine and generator I had installed Fleetguard double filters. The unit mounted filters are the last line of defense. It is common sense to have additional fuel filters in front of these units.
The SBMAR double filtration kits can be fitted with squeeze bulbs. I had changed fuel feed lines and filters for generator and engine. Thanks to the squeeze bulbs I was able to bleed the air at the Fleetguard filters sufficiently that generator and engine kept running without additional bleeding at the unit itself! HIGHLY RECOMMENDED!
In total there are four double multi stage fuel filtration kits:
- one in the generator supply
- one in the fuel transfer pump supply
- two for the engine supply
Fuel filter setup for engine supply
The fuel line to the engine runs through these two double filtration systems.
Either left or right side is selected to filter then fuel. If one filter is clogged the filters on the opposite side can be selected for filtration by the T-valve in the middle.
After filter change the new filters can be vented with the squeeze bulb. If you can tolerate to work in the engine room while the engine is running: the engine does not require to be stopped for fuel filter change
The fuel transfer pump
The shipyard had installed a “Seaflow” gear pump for fuel transfer.
I considered it an amps to noise converter: Used probably more energy to produce the squeaking metallic noise than pumping fuel.
I had to re-locate pump and filter anyway. It blocked the operation of the fuel purifier.
It was a no-brainer to change the pump: that pump is the main transfer pump between the tanks!
Now a membrane pump (constant duty, self priming, run-dry proof, four times the price) is doing the work.