Wednesday, May 11, 2011

Dirty Jobs

New Bern, NC
35 05.91 N 077 01.95 W

I spent yesterday and today doing some dirty jobs.  Not as dirty as those on the TV show Dirty Jobs, but nasty nonetheless.  

Recently I wrote that one must enjoy working on the boat to be a boat owner.  True, but some jobs are more difficult than others.

These jobs have been on my to-do list for some time.

First, I cleaned the engine compartment.   Most boaters don't have to do this nearly as often as I do.  Why is that?  Because a "feature" of Tarwathie is that access to the engine compartment is easy because  I can lift off the cockpit floor.   Another feature is generous lazarette storage in bins under the cockpit seats.  I've gradually learned that both features provide ways for dirt to get into the compartment.   I ought to be more careful to clean the floor and the recessed lips around the floor before lifting it.  I also ought to think about providing air and water tight liners for the lazarette bins.

Next, I cleaned the engine heat exchanger.   This is something I ought to do every year, but it has been two (three?) years since I did it last.  The reason I avoid it is that it is so difficult to do.  The parts that seal it in to the engine become frozen in place with lime and salt.  They are devilishly hard to work with.   I'm supposed to remove the caps at each end, but this time I tried for two days to remove the forward cap.  It wouldn't budge.  I finally gave up.   That means I can't replace the o-ring on the forward cap as I should.

Anyhow, we noticed that the engine ran 10-15 degrees hotter than normal under load.  That is a sure sign that cleaning the heat exchanger could not be postponed any longer.


The heat exchanger after removal before cleaning.

The procedure is to remove the heat exchanger.   Brush it off.  Soak it in acid.  Then put everything back together.  Above the picture shows it before any cleaning.  Look closely and you can see a 1/4 inch thick coat of crud that covered about 1/3 of the surface.   Also, about 20% of the 60 tubes were blocked with crud.  I think the crud was mostly salt.  (Hmm, if the external crud really is salt, it must mean that the seals aren't tight and salt water contaminates the coolant.  I see no signs of corrosion in there, but I can't think of any other source of crud on the primary side.  Maybe I should have licked the crud to taste it.   Double yuck.)

Third, I had to repack and tighten the stuffing box.  That is the part that allows the propeller shaft to penetrate from the dry inside to outside the hull, while not letting water in.   It had been dripping recently, and needed work.  This job is hard to do because I almost have to stand on my head on the transmission to reach the stuffing box and put wrenches to it.  It is very uncomfortable.   

I once helped Ray repack his stuffing box on his trawler.  It was amazing how much room there was in his compartment compared to mine, and how easy that made it to do the job  Spaces are very crowded in a little sailboat; especially the engine compartment in a double-ended boat with a tapered stern.

Fourth I re-plumbed the sea water cooling supply hoses.  Why?  Just because the old hoses were old.  It was a precautionary move.   This job was dirty because it required part of the job to be done in the space under the engine pan.  There is a water tight pan under the engine.  Under that pan there is a two inch thick space to the bottom of the hull.  The space is very tight.  I've never worked in there before.  I felt something loose in there and pulled it out.  It was a stainless clamp and two bolts that must have been meant to clamp something down in place.   It isn't doing it's job now.  I have no idea what it was supposed to be clamping.

One more dirty job to do soon.   I have to remove the toilet and replace the internal parts.  It is working as is but not working to peak efficiency.  While it's apart, I have to clean away the encrusted salt that coats everything.



1 comment:

  1. Dick,
    Your heat exchanger core looks exactly like mine. I don't remember what engine you have. Mine's a Beta and yesterday I gave up on trying to remove the end caps, fearful that I'd break something. I am using precious funds meant for improvements on Robin to pay for a Beta mechanic to take the thing apart. I hadn't changed the zinc in the heat exchanger for two years and when I removed it, there was gray jelly where the zinc should be. I'm hoping that doesn't explain all the corrosion that's gluing the end caps on.
    I was forced to work on the heat exchanger because when I started the engine yesterday morning, the water coming out the exhaust was fitful and the bilge pump was running full force. When I opened the engine compartment I saw water shooting out of the bolt hole in the front of the heat exchanger. The bolt had sheared off.
    Then I discovered when I went to drain the coolant to work on the heat exchanger that there was no petcock low on the block where there had been one two years ago. It apparently had corroded off.
    Then when I went to use the lower hose to draing the antifreeze, what came out was brown and very un-antifreeze-like. And there wasn't much of it. I am guessing that the antifreeze drained out where the petcock should have been. All in all, a scary situation. Hope yours turns out better.
    Doug

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