Sunday, January 24, 2010

Who Needs a Diagnosis, I'll Just Treat the Symptom

January 23, 2010
Vero Beach FL

Today the Budget Committee laundered 4 loads of dirty stuff. There was more than 4 loads to be done but the BC took pity on another overburdened boat wife and both boats ended up getting not all laundry done but at least the important stuff clean. Had the BC not achieved this we could not have attended the dock party scheduled for every Saturday afternoon - 4 to dusk.

While the BC idled away her afternoon waiting for the clothes cleaning machines to do their work (yes, yes, this is written jokingly) I busied myself correcting the plumbing mess created when I replaced the freshwater pump on Thursday.

Flashback to Thursday which was the day of the repair which lead to the mess:

In point of fact the freshwater pump did not quit, quite the reverse. Rather all at once it just started to pump - and would not quit. It ran and ran and as it did it began to sound increasingly like a runaway locomotive as each of its four little pump pistons slammed themselves mercilessly against the column of water contained in each tiny cylinder. When a system fails on Meredith we have a procedure:

1. Immediately go to whatever part of the failed system we last "fixed". Almost always your current problem is caused by your last enhancement or "fix".

2. In those rare cases where procedure #1 does not work we start with the simplest fix and work our way up through each increasingly difficult fix until we find something that works.

3. If neither #1 nor #2 produce any useful results we read the manual and Nigel Calder's excellent Boatowners manual.

4. If all else fails we look at the cost of a new part or system. Then we check on the cost of repair. When the cost of repair exceeds 1/2 the cost of a new part or system we replace the whole system. Now there is some art to this. Any time estimate by a repairman must be increased by 25% to 100%. Cost of parts suffer a similar inflation factor. Cruisers have not generally had good experience with repairpersons.

Prior to Thursday we had not worked on the pump for a couple of years so it was not my fault. The water tank was full (an empty tank causes the pump to run while it tries futilely to build up water pressure by pumping air. Water is incompressible while air is eminently not.

The taps were all off. We checked the taps for leaks. None were found.

The pump continued to run.

Moving up the "difficulty" chain we had to check the freshwater filter which is placed in the inlet to the pump. It traps any large particles or scum which may have found their way into the water system before the detritus can destroy the pump itself. If the filter is plugged the pump can get no water and again finds itself pushing hard to build water pressure when no water is available.

Now here is the thing about difficulty: the filter is attached to the inlet side of the pump and the pump is located in a locker at the far aft end of the quarterberth.

The Budget Committee had just filled that locker with 3 months worth of canned goods (87 cans in total) in preparation for our sail to Cuba and beyond. Every single can had to be removed from the locker before we could access the pump.

As the BC emptied the locker I dug out the spare pump (we carry 2) and readied it for installation. It needed new electrical connectors installed and one of the power leads needed to be lengthened. Preparing the spare pump was jumping ahead a step as if the filter was plugged we would clean it the repair would be done. I would not then need to install the spare pump. However the BC was working hard in cramped quarters undoing hours of careful packing and inventorying and I found myself shamed into "keeping busy" for the duration.

When we had access to the pump it was obvious the filter was not the problem. It was pristine. This surprised me.

So here was the situation: the pump was running incessantly, the tanks were full, the taps were off, there were no discoverable leaks and the filter was clear. It must be the pump. Good job I had readied the spare eh?

The spare went in in ten minutes and the system tested fine. The pump ran only when the taps were opened. Success.

We figured the pump head on the old pump had worn out and could not hold the 35 pounds of pressure the pump had to hold for the freshwater system to work. Being a cruiser I did not dispose of the old pump as I might need it some day for parts. Instead I carefully stored it with the two other broken pumps which I am saving for the same reason.

The job done the BC carefully repacked the 87 cans (she counted) she had removed from the locker and we replaced the cushions, blanket, spare sunbrella cloth, shade cover, spare stainless rod, books and charts and binoculars to their proper place. The quarterberth is our garage.

Success however is a fickle friend and this ends the flashback and returns us to the beginning of the blog.

The night of the repair as we were lying in bed reading we heard the bilge pump alarm go off. This was suspicious as it had not rained and the engine had not been running so no water was coming in the stuffing box. There should be no other source of outside water getting into the boat. There wasn't.

Moments later the freshwater pump cycled on for 5 seconds.

Half an hour after that the freshwater pump cycled again, only for 5 seconds.

We spent an unslumbrous night listening to the intermittent cycling of the freshwater pump and the less frequent but related operating of the bilge pump signaled by the bilge pump audible alarm.

I spent an hour looking at all the parts of the freshwater system trying to find a leak. At 3 a.m. staring bleary eyed into the bilge the problem presented itself. A very fine and intermittent spray of water was emitting at irregular intervals from a point where the freshwater hose had been cut and repaired by an earlier owner.

We now had a ready fix for the obvious problem but the whole freshwater system was now suspect. In replacing the pump we had repaired only a symptom mistaking it for a cause. It was possible that the intermittent spray leak was the cause of the earlier loss of pressure and that replacement of the pump had not been necessary. We had not looked far enough into the problem.

While the BC did the laundry I removed the old hose and examined the connections. They were rotten. Every connection and there were 10, all rotten. Any one or all of them could have give away at any moment. Had a hose given while we were off the boat the pump would have quickly pumped all 100 gallons of freshwater in our forward tank into the bilge.

Replacing the connectors and hose was a simple task but it required that I once again access the freshwater pump. Which in turn required that I unpack the aft locker, all 87 items, yet again, to permit access. All of which explains why I undertook the job while the BC was off the boat doing the laundry.

All the old connections have been redone and are sound.

The Budget Committee has repacked the aft locker a third and final time in a week (all 87 items). BC has ceased mumbling unheard comments and I am reducing her sedatives.

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