Saturday, September 17, 2011

Bilge Work: The Underside of Making for Sevilla

2011 09 17

last days in Portimao

The Punishment Room - Behave Or You Have to Work in the Bilge

Before heading off to Seville we decided we should replace an ailing bilge pump switch.  Our existing bilge pump switch had failed.  We knew this because the Budget Committee, being Dutch trained, is an inveterate worrier and checked the bilge several times during our interesting voyage from Azores to Portugal.  On one of her multiple checks she found the bilge full of water; the bilge filling continually with water draining along the entire length of the boat as Meredith was pounded with green water for days on end.

Fortunately it was only the switch that failed and the manual override worked to energize the pump and clear the accumulated salt water.

That the automatic switch had failed was not a total shock.  On Meredith this is a common problem and we seem to have to replace the bilge pump switch every year or two.  Since the switch may one day save our lives we are inclined to keep it well maintained.  Of course they still fail and never at a good time.

The switch is a simple device: usually a float that closes an electrical contact when the water (loose term) rises and causes the float to rise to  a predetermined level.  Lately newer solid state switches with no moving parts have come onto the market.  Our experience with these is that they are superb devices that have a working life of no more than six to eight months.  Then they fail.  We have tried two, both failed.  The last was the one in Meredith when we left Azores.  Now we just use float switches.

Some boats have wonderfully clean bilges; compartments that could be used by Mr. Clean, or Comet as a testament to the wonders of their respective cleaning products.  Not so Meredith.

Even though I never spill a drop when changing engine oil there is a ubiquitous film of black hydrocarbon covering the pool of liquid (for I dare not call it "water") filling my bilge.  Even though no tissue paper of any kind goes anywhere on Meredith save into the garbage bag in the sink (save only for the toilet paper which goes down the head on Meredith) there is always a floating mass of indescribably foul cellulose obstructing my bilge pump pump intakes.  Where does this stuff come from?

Today I found the top off a jar of peanut butter floating in the bilge.  We have never thrown out a topless peanut butter container.  How is it possible for an orphaned peanut butter lid to be floating in my bilge?

It was.  Six feet down which made recovering it just so special.

Bilge pump switches are installed in the lowest point in the boat where they spend their lives half covered with a noxious mixture of oil, fuel, dirt and filth; all the unwanted material from every other level on the boat runs to the bilge.  If you ever wonder how the term "low point" came to have such negative connotation spend only a few minutes in the bilge. Clarity will find you; hopefully before you succumb.

Anyway, bilge pump switches need to be checked often and replaced when they are suspect.  About all you can do to service a switch is clear it of accumulated muck, grease and animal skeletons and check for cracks in its plastic housing.  Fail to replace the switch at the earliest sign of a problem and you may wake up one night to find your sleeping berth has the declined in elevation to water level.

Worse, if you have only small amounts of water coming into your boat a sticky switch will fail to clear the material and then you can enjoy the incredible heady odour that consumes the entire boat when a small body of water sits stagnant for a month in a dark warm space.

Usually it is corrosion that gets our switches and that most often in the wiring.  It seems a constant bath of hydrocarbons leaves a switch well lubricated and, save for the inevitable black film, very clean.  The hydrocarbon bath does have a deleterious effect on the life of coating on wiring and the plastic switch body however.

Both of our "electronic" switches failed due to cracks in the external wiring.

There are a couple of adaptations we have made to our bilge pump circuit that you might consider:

No "Automatic" Setting

We have the normal bilge pump switch with two settings: automatic, which turns on the bilge pump switch and manual which energizes the pump when you move the switch to that setting.

We eliminated the "automatic" setting on the bilge pump switch and wired the bilge pump switch directly to the batteries.  Why would you ever want to turn off the bilge pump switch?

One year we left the boat in the water in Green Cove Springs while we returned to Canada for Christmas.  Somehow we bumped the bilge pump switch and turned off the automatic feature so the bilge pump switch did not run.  This will never happen again.

Piezo Electric Buzzer

we installed an inexpensive ($4 at Radio Shack) piezo electric buzzer into the bilge pump circuit.  When the bilge pump runs everyone on board hears it.  That way we can keep track if there is a leak problem.

The wiring is very simple.  At the back of the bilge pump switch find the terminal that connects to the "manual" switch, ie. that tests positive when the "manual" switch is activated.  Connect the positive (red) wire on the buzzer to that terminal.  Wire the black wire on the buzzer to the negative bus.    Every time your bilge pump runs, even on automatic, the buzzer will sound.

Unless the bilge pump switch has failed.

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