Lived onboard Hadar

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Tuesday, November 13, 2012

Panic Stations

Last night, as I normally do, I started up the generator on my way out to take Paddy for his walk, this was at about 6:00pm. As I walked back I heard it was not running. Jo said it had just stopped whilst I was out. Bearing in mind Paddy’s walks only take five minutes!

It could only be one of three things, fuel, water or oil. The generator has built in sensors to shut the generator down should it overheat or lose oil pressure. However in my haste to get it sorted and up and running before 7:00pm to give us an hour’s running to recharge the batteries, I missed the obvious. First I changed the fuel filter, which by the looks of it did need changing. This didn’t fix it. I checked the oil level which was ok, so it could only be the water cooling. I suspected it could be the impellor on the water pump for the skin tank circuit, which upon inspection did look well chewed up, especially when I got it out, it certainly wouldn’t have lasted much longer. It was a struggle to get the new impellor in, a really tight fit, and in an awkward place to get to. However this did not cure the problem, and time was getting on, 7:30pm to be precise, so we decided to pole the boat into the basin and onto the sanitary station mooring to connect our landline overnight, and to carry on fixing the generator in the morning. I couldn’t drive the boat in with the engine because the gearbox is in bits at the moment.

This morning we were both up early, and set about stripping everything down to get to the generator again. This time though we did it properly and removed the shelf over the generator, which now meant I could get to the header tank for the engine cooling circuit. It was a bit short of water, so I topped it up, and we then moved back onto our winter mooring on the towpath before restarting the generator, problem solved.

The only time I get to check this header tank is when I do an oil change, simply because I need to remove the shelf and all its contents to get to it. Whilst we had everything removed I did an oil change, which I had thought was overdue, but it wasn’t. the next oil change should have been at 1300 hours of use, but for whatever reason, last night I had misread the gauge as being 1400 hours! This morning having changed the oil and filter, I discovered that the gauge was showing 1200 hours, so not overdue, but never mind it is done now, better too early than too late.

For some time now I have been thinking of changing the cooling circuit for the generator for a number of reasons. At present the generator has 2 cooling circuits. Because it is supplied to be used mostly for boats that do not have skin tank cooling which is used in narrow boats (a skin tank is a tank welded to the inside of the hull and is equivalent to a radiator in a car, but uses the cooling of the canal water on the outside to remove the heat) and use what is called “raw water” drawn from outside the boat, and because this could be salt water which it would be in most applications for marine generators, it is not passed through the engine directly, but uses a heat exchanger, so the water passing through the engine is not salt water. So I have water circulating through the engine and heat exchanger as one circuit, and the other side of the exchanger to the skin tank is the second circuit.

My thought has been to cut out the heat exchanger and have the engine directly cooled from the skin tank. After all this is how the main engine is cooled, directly. This would have a number of advantages for us as follows:-

  1. It would remove the heat exchanger from the circuit, so the cooling would be more efficient as it would be directly cooled, especially during the stifling hot summers we have!
  2. The existing external header tank for the skin tank circuit, which is easy to get to, to check and top up, would now be used for just the one circuit, thus it will be easier to keep a check on the one water level, without having to remove all the shelf and everything on it to check the engines separate header tank. This header tank would still be in circuit, but would become redundant in its use, being superseded by the external header tank. As it is a sealed tank with a pressure cap, same as on a car radiator, and with an external header tank removing any pressure from the circuit, it would no longer take any part in the cooling circuit, other than just having water pass through it.
  3. It would make the “raw water” pump redundant, and by removing the fan belt for this pump, it would reduce the power drain from the engine to drive this pump , which could be between 5-10bhp, thus saving fuel in the long run.
  4. By removing this pump, it would also negate the weak link of the impellor failing in it, something less to worry about, and to have replacements for, along with the spare fans belts for this pump.

Fortunately changing the cooling circuits will be easy to do, as in the past when we attempted unsuccessfully to use the cooling water to heat the calorifier ( for non-boating people, the hot water tank), we had already broken into the existing pipework on the generator, and this break is very close to the 2 pipes from the skin tank, so all I have to do is break the engine circuit at this point and connect the skin tank pipes coming from either side of the skin tank. I just have to make sure the direction of flow through the skin tank is correct. All I need is 2 right angle bends in HEP2O (easy connect plastic piping system used in boats), and a hose clip to be able to change it. Another job for another day soon.

Hopefully this afternoon I can get the gearbox rebuilt and back to working order. Nothing major, just replacing a worn oil seal, but a job that I started a few days ago, but have had a few interruptions since which have prevented me from putting it all back together again.

Keith.

 

P.S.

I did get the gearbox rebuilt in the afternoon, we will find out if it is ok when we set off from here next year. I took advantage of having the floor up to top up the starter battery, which didn’t need a lot.

Keith

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