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…

Nov 222012

The thruster first gave up in Las Plamas in the Canaries almost exactly a year ago. Then it was the gearbox that called it quits. Since then the control electronics and the up/down motors gave up too, due to salt water penetration.

Now I have a new gearbox and a new controller, and I actually managed to find a small garage in the suburbs of Maldonado who were able to re-wind the shorted up/down motor.

So everything was put back together with a lot more careful water proofing than the original product had. The up/down motors were originally sealed with ordinary PVC tape, the kind you use for household electrical work… Now I have surface treated the motors with a metal epoxy primer, and carefully sealed them using proper marine products.

And everything actually works. Horray!

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!

Nov 042011

The Journeyman is supposed to be powered only by the wind and the sun. (Except it has an engine of course, but we’re talking about when we are sailing her!)

However my original ambitions that all electrical power was to come from the sun turns out to be a little optimistic. Especially when we are at anchor in cloudy weather, with lots of people on board using computers and staying up late at night with the lights on.

So to allow this to happen I installed a wind generator today. This will give a bit of extra juice during cloudy days, and also runs through the night. It’s much less power than the solar panels, but hopefully a good enough complement.

Apr 132011

I looked at a lot of commercially available electric power monitors, and none of them really suited me. Either they didn’t support dual voltages, or they had too small measurement shunts that couldn’t handle the 200A loads I have as worst case.

Or they were of the “over computerized” type who insists on providing some kind of useless (as in “never accurate”) tank meter for the battery.

So I put together my own monitor that gives me enough info to roughly know the system state, given that I also know the parameters a “tank meter” doesn’t. Like the weather, for example. So in the image below, given that it is a cloudy morning at about 9h00, the charge rate of 6.7A is quite nice…