Generator Raw Water Impellar

In an ideal world yes, obviously the makers of this boat do not agree, my whole point was that it is very possible that they do not agree.

No... in a real world. If you had ever been responsible for keeping a marine engine running, it would be blatantly clear to you that Carver made an engineering mistake when they chose to place this pump where it is. There is no comparison to an aquarium here. I can almost guarantee that this is a rubber impellor which, in all likelihood, needs to be replaced often. This will sometimes need to be done when the machinery is still hot and the vessel may even be drifting around in a seaway.

I've watched many of your posts over the past couple of weeks with great amusement. To be quite honest, you seem like a pretty smart kid (perhaps even really smart) who just talks (or types in this case) for the simple pleasure of trying to participate in a conversation. There is no doubt that some of your technical posts have added to the flow of information, so please stick to those until you've actually laid your hands on the piece of machinery (or similar) in question.

I'm not sure where you're headed with your studies, but if you pay close attention here you may learn something and even prevent yourself from becoming the kind of engineer who placed this water pump in such an inaccessible place.

I study Biology, I see the worst engineering imaginable, pathways that zig zag back and forth and awkwardly reach when a simple straight foreward approach would simplify things so greatly, I'm quite used to and comfortable with seeing things done in exactly the wrong way (our retinas for instance, are backwards, its like spending thousands of dollars extra to buy the very best camera available, then smearing it with petroleum jelly).

This is not a big boat, and I would imagine that it would have a battery on it, can it run with out the genny for a ways? Granted you cannot cook or watch TV or even read a book at night, but I would imagine that loosing the generator wouldn't leave you stranded (if so then that's the big design flaw), you can go for a while while the genny cools down and then reach over a warm piece of equipment to fix it. I'm sure that had they left enough room for the impeller to be reachable that people would complain about the genny sticking out into the space, and how cramped it was. Euclidean geometry sucks.

Well, that about sums it up. Wrong on both counts. If the drift of the responses to your posts in this thread are still beyond your comprehension, let me put it to you very bluntly ... you are in over your head.

You are writing about something you have demonstrated very well that you have no experience or knowledge and are just being argumentative. In any event your attempts to cover your butt are just making your posts look even more ridiculous.

I suggest you just lurk for a while and try to learn from the very experienced folk here who have experience and knowledge of the machinery under discussion. Go get some hands on experience and some training in the art and science before you try to tell them they are wrong.

Hi,

I was not being aggressive to you with my posts.

I was merely repeating the point that you seem to want to partake here and reply to everything that comes up whether you have any ideas what the situation of problem actually is.

It's not a race to run up the max number of posts in the shortest time possible.

As suggested by other members here who have a high number of posts you could learn by simply keeping a track of things you find interesting, you do not have to partake of every conversation with drivel just to keep it alive.

Also, I do not think there needs to be any fundamental changes made to the way this site is operated as you have suggested. It works fine for me and a lot of others so if it isn't working for you then there is such a thing as self censorship- Don't log in or browse the place if you don't like what you read or are being told.

Opcn,

Both of the above posts by Ken Bracewell and Marmot accurately sum up the feelings of several more people here, myself included.

It is time to bring this to an end. I encourage you to find another forum, where your knowledge is better suited to the topic.

Please refrain from further posting at YF.

Marmot, you seem to be forgetting the part where I was right, I.e. it is believable that they built the boat that way, because they did build the boat that way.

In a gear pump there are open spaces that go on a long sweeping arc around the edge of the pump housing and then they are closed on the return by the interface with the other gear, In the jabra system there are open spaces that go on a long sweeping arc around the edge of the pump housing and are closed on the return by the interface with the constricted wall of the housing, they work on the exact same principle and the gear pump came first, so I'm going to have to stick with my assertion that the jabra system is a mimic of the gear system.

I never argued that it was superior from a maintanence stand point, just that it was believable. You stop putting words in my mouth and instantly I stop being wrong, so stop putting words in my mouth. Thats a technique that can be used to make anyone wrong, inspite of how right they might be.

If someone wants to prove that all production boats use the jabra system for generators and have the same drawbacks then I will happily conceid the point that no impeller on a generator will last a decade.

@Pascal, as for the trip being over that is a cost (not as large as being stranded) that I'm sure went through the cost benefit analysis. The point being that the costs nd benefits are comperable, and that some people will choose different paths.

Thank you.

It's what my spellcheck autocorrect Jabsco to for some reason.

And yet your autocorrect leaves "conceid" rather than changing it to concede?

You really don't add up.

My spell check is squirrelly and shuts its self off, which is why I have so many posts with good spelling in the first half and bad in the second. Would one of the admins please delete my account, there does not seem to be a mechanism for me to do that myself, thanks.

See- Self Censorship at it's best- Someone please put this poster out of his misery and hit the delete button.

By the way in case you are lurking 10 yrs is 87,600 Hrs, the genset engine unless running on Natural Gas would have been rebuilt at least 8 times if going by std CAT Recommendations, they also ask for the flexible impeller Jabsco Impellers to be checked at 2500 hrs but I have never seen one that could be re used at that life span so check them at 2000 hrs as part of the 250 hr service and again at 2250 then replace at 2500. Doing this I have never had one fail and cause me problems.This time frame is equal to just over 100 days on a large motor yacht or under 200 if you are doing equal cycles between two units and run them in parallel for a while each day.

It is a range of Bluetooth Wireless Headsets for Mobile Phones etc.

Thats why I asked him to delete my account.

An impellor would last a lot longer if it is running 24/7 and not stopped for weeks at a time and then re-started etc. This is what kills them, they stay stopped in one spot and some of the vanes get deformed, they then run dry for a few seconds until they prime themselves. I've never seen a generator where the seawater pump was at a heighth below the waterline. Also a partially blocked heat exchanger will also prematurely kill impellors because it's harder for it to prime and the head pressure is much more on the raw water pump. I've never seen a generator impellor last more then 2 years, period.