Throttle and generator changes

As always with a boat, there were a few niggly things that we need to get done before the start of the season. The first of these is the throttle on Mariadz.  This is located on the steering binnacle next to the forward facing radar control but Maria has always struggled when the engine is in gear. Out of gear, the throttle is smooth and works a treat, having changed the throttle cable some years ago, but in gear it is incredibly stiff and you find yourself using excessive force, going too high on the revs and then having to pull back to where you wanted to be. This is something we wanted to have fixed before starting a new season.

helmWe had spoken to Lindsay at Seapower about this some time ago and there was concern that we may need to replace the entire throttle control with a completely new and very different unit. The first job though was to check that we didn’t have issues with the throttle cable and particularly the gear cable that allows you to select between forward, neutral and astern. This was one of the jobs arranged for while we were away skiing in Austria. On our return from holiday, Maria was planning to turn the boat around so she was bows-to the pontoon. This is our preferred wat round and gives her a nice view over the stern to Ipswich Centre. It provided us an opportunity to test the new setup. After the work was done, there was a complete lack of swearing when Maria was turning the boat around so I think we have a result!

The second job that had been outstanding for a while were the calorifier pipes for the generator. These move the heat from the generator cooling system into the hot water tank, thereby heating up the hot water and also cooling the engine coolant. We have this setup from the main engine but there were a couple of reasons for getting the more complex setup that supported twin coolant inputs to the hot water tank. Firstly, we have a source of heat in the generator coolant which we would be wasting, I don’t like that. Secondly, we like to have redundancy in our systems so there is no single point of failure. We can now heat water electrically on the shorepower (or generator), electrically using the inverter charger and the batteries (very sparingly), from the engine coolant and now from the generator coolant. Surely one of those must work at any given point in time? If not I have a solar bag, that heats water from the sun, on deck!

There was one consideration regarding this which related to the use of the generator. It is important to work the generator when it is turned on. The last generator was 11.5kW and had been continually used at very low loads which killed it. It was scrap after 700 hours. Although in retrospect we could have rebuilt it, the advice at the time was not to and hopefully we will have none of the issues that the last owners had with a flaky generator. imageTo avoid this problem, we took the decision to buy a generator with a lower power output (7kW) so that we were always using a high proportion of its capacity. In the few instances where we need more than this for a very short period, the inverter charger could pull from the batteries but this was likely to be for seconds and so wouldn’t impact the batteries too much.

The electrical part of the hot water system requires 1kW which is a good start load for the generator, especially when you add battery chargers and aircon units. So by using the pipes and removing that element of the load, I may make my job of loading the generator harder. I guess I can always switch off the heated water element if I want!

Lindsay had to do some design work with the Onan generator to get this setup to work well but it is now a very neat installation. Unfortunately as part of the testing of the new setup, Lindsay discovered that five vanes from the impeller, that drives the cold water around the engine, had broken.   D78BCC4B-7405-46FC-8B71-412EE38F6AFAThis has been in place exactly two years and had around 70 hours of use so a little worrying. Of course a broken impeller is not good news and we are grateful that the generator hadn’t overheated because of the lack of water flowing through the system. We are now investigating what has happened but I understand that we may need to be more careful at checking the generator when it hasn’t been used for a little while. I suspect more frequent changes of impeller will be required too.

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