Thursday, May 26, 2011

May 23, 2011.

Yesterday a boat owner called and said “send me an ace mechanic”. Ace was sick, so they sent me.

I drove out to the owner’s home and his large power yacht was up on a boat lift. It seemed his generator wasn’t spewing water out the exhaust. His theory was that there was a raw water intake shut off valve that he couldn’t find. It’s only a 3 foot piece of hose so I could see flaws in his theory.

With a flashlight and mirror I could see that all the paint was gone from the little door that covered the impeller. I figured that the pump must have gotten hot as hell to have all the paint fall off. So I was suspecting a bad impeller as I finagled my way into a space that I was not built to fit into.

I could only get one arm and half my head into the proximity of the pump. On the plus side, there were only 4 bolts holding the little door in place. Hex heads at that, no jerking around with a screwdriver and slots that I couldn’t see.

I got the little door off, stuck my fingers in and the pump body was ……empty. WTF? Where did the impeller go? With my mirror I could just make out the metal bushing that lives in the center of these little rubber impellers. Not only was every vane gone but the entire rubber hub was completely gone.

I found most of it living in the heat exchanger.
As it turned out, when I asked the owner to lower the boat so we could try out the new impeller, a clue to the cause of the problem became apparent. He lowered the boat until the water gently lapped at the hull…….but not enough to let the water reach the generator’s intake.

So the story is, he and his buddies sit out on the boat enjoying adult beverages with the generator running the A/C. He’s at his own dock with shore power, but he’d rather use the generator??? He told me he doesn’t like to put the boat completely down because then it tries to float off the boat lift. He was actually skeptical when I explained to him that the boat had to be IN the water before he could fire up the generator. When I walked away he was happy that his generator is working and I was completely dumbfounded.

Today’s amusement for me came in the form of a large powercat. The owner was complaining of an intermittent electrical problem. It seemed that when he was watching television, once in a while the 12 volt system would shut down momentarily. Intermittent problems are ALWAYS a pain in the ass to find. <- I think that’s one of the 12 platinum rules of boating. Anyway….

He has 3 battery banks onboard; one starting battery for each engine, and the house bank. I checked both starting batteries and found them in good health. I almost fell off the boat when I opened up the compartment where the house bank lives. The house bank consisted of a single pair of 6 volt batteries. The house *banks* resting voltage was barely 12 volts and when I applied a moderate load the voltage plummeted to 11 volts.

I figured that he was watching TV with a light or two on and maybe a fan or three and when the voltage dropped low enough, the TV kicked off because of a low voltage condition. He’s got to replace the 2 golf cart batteries anyway so I’m pretty sure that’ll solve the problem. I also recommended that since he has the room perhaps he could go with 4 golf carts and end up with a reasonably sized battery bank. OMG

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