Size does matter

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Nov 282012

The crazy Australians that built my hydraulic steering system had a tendency to super-size everything. Not a bad thing in a steering system actually. But the auto-pilot got super-sized too, and that was maybe not perfect. With the original pump the HO/HO time is about 2.5 seconds, which is waaay to fast. So I have had the system running throttled. But then it consumes too much power, so the batteries run out…

Now I’m replacing it with a more sensible sized unit…

Fuel woes: Be gone!

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Sep 252012

I’ve had problems with the engine fuel on a few occasions, as the faithful readers of this blog will remember. Very annoying. It never happened in critical situations, though. But I don’t want to tempt fate… So I just finished putting together the new fuel filter system. Maybe it’s an overkill this time, but it should provide much better reliability compared to the single CAV-type water separator that was originally put in there.

So we have:

  • QL Decontaminator. Not sure if these ones actually work, maybe it’s just fluff… Because I’ve had a bit of slime growth despite having it before…
  • Dual Racor Turbine filter separators with large water reservoirs and the possibility to empty water under operation.
  • Valves to switch filter bank under operation.
  • Take-offs on input and output to facilitate scrubbing and other maintenance operations.

Plus the whole thing is now mounted outside the engine compartment, so it’s much easier to check for excess water in the separator.

The product disappointments continue

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Apr 192012

I think I have enough trouble dealing with my own mistakes. But on top of that I have to deal with a multitude of standard products that fail. Here’s another one to add to the list: Today I was investigating a leak in one of the manual bilge pumps. It is less than two years old, but when I took it apart still it turned out it was the membrane that was cracked.

Now I deliberately bough rather expensive Johnson SPX pumps. And still they do not even last this long before the material fails. I guess as usual, the marine product manufacturers are laughing all the way to the bank….

Apr 012012

Today was a day dedicated to the fridge and freezer. I had noticed that the fridge especially had very long run times, and was causing a bit of battery drain. When I had a look at it, the piping outside the actual fridge was covered in ice. This of course seemed a bit wrong, I was obviously wasting quite a bit of energy cooling down the air in the machine room!

So I did a bit of studying. Apparently a cooling system like this needs to have the right amount of carrier gas inside it. If the pressure is not right the system will not work well. Excess icing on the pipes outside the fridge indicates that the pressure is too high. In this case the coolant does not evaporate completely in the evaporator inside the fridge. Thus there is some fluid coolant leaving the fridge, which then evaporates in the pipes on the way to the compressor. This makes the system inefficient.

So all I needed to do to fix the problem was to let a bit of coolant out, which is easy enough. Getting it back in is a different story, so I was very careful in the beginning with how much gas to let out. Working in small increments and waiting maybe 10-15 minutes for the system to stabilize before letting out more.

This image shows the process when it is almost complete. You can see a small length of frost along the pipe in the center. When I started this pipe was completely covered in a thick crust of ice. As more and more gas is let out, the length of pipe that freezes gets shorter and shorter. And in the end the whole visible length of pipe is free from frost.

The compressor now runs significantly shorter times, while keeping the fridge cooler than before. Hooray!