[Sentoa] Heat exchanger

[Mike Pedersen]

Hello James,

I cannot help you on your stray current, as boat electrical systems are not
my forte (even after repetative Calder readings).

However, I could suggest adding some Belzona 1221 and 2311 to the repair
kit.  1291 looks promising as well, although I have never used it.

No interest in the product, although I have used it often in the Navy and
now in industry.

Mike Pedersen
NORTHERN SPY, NT26-028
Powell River, BC

On Mon, Sep 14, 2009 at 6:26 PM, <tugs4me at comcast.net> wrote:

>  Fellow tuggers,
>
> This is a "heads up" and a request for information relating to heat
> exchanger experiences.  Saturday morning in pre-departure check before
> leaving with several other tugs for Half Moon Bay, I found salt crystals on
> the tool chest and damp towels and boxes in my "junk box" in the engine room
> on the starboard side equipment deck just forward of the house battery
> bank.  In addition the bilge had about 1 1/2 inches of water though I try to
> keep it dry as a bone.  About a week ago I had about an hour run to the fuel
> dock and all seemed well when I returned but I did not check the engine room
> or bilge after I tied up.
>
> Just before departure time I started the main diesel, lifted the hatch and
> saw a 1/8" inch stream of (salt) water arcing across the engine room.  With
> assistance of Cal Robie ( EMIKO) I went into the engine room and Cal
> restarted the main which immediately exhibited a "fountain" near the aft end
> of the heat exchanger just below the elbow leading to the exhaust elbow.  (
> I carry a number of hose clamps up to about 10" diameter on the assumtion
> that a couple hose clamps and duct tape will provide an emergency patch on a
> hose but this perforation was directly below the elbow, thereby precluding
> that potential temporary repair had I needed it to get home.)   I checked
> the zinc and found about 60% remaining.  So, instead of a nice trip down the
> coast I had an opportunity to enjoy draining the coolant as well as draining
> the aftercooler to replace those zincs, upper about 70% left, the lower
> about 30%, then removing the heat exchanger and finally cleaning up salt
> water residue and sponging 3-4 gallons of salt water from the bilge.
>
> Will meet with Chuck's Marine in the morning to have him inspect the heat
> exchanger to see if it can be repaired and to determine if it failed due to
> a defect or electrolysis.  Meanwhile, I mixed a major gin and tonic and
> contacted the Cummins distributor for price and availability of a new Part
> #4020101.  Price is $1,101 but not in stock locally or at the factory.  A
> little bing search found it available at inetmarine.com for $591.54 plus
> shipping and handling.  (I asked what it cost to just ship it and not handle
> it.)  They have it built by Seakamp Engineering in Bellingham, WA and I was
> assured it will be fabricated and shipped within about 2-3 days.  I did
> order the racing model upgrade so SFBANTA members you are forewarned, soon
> there will be a new Alpha male on the Bay.
>
> Here's the puzzle.  I give myself an A- to B+ overall on zinc anode
> maintenance.  About 2 1/2 years ago I had to replace one of the Marine Air
> reverse cycle units due to a failure the tech said could have been caused by
> electrolysis.  There are no replaceable zincs on the A/C units.   I'm
> suspecting a "stray current" issue and will start serious work to determine
> if that is my problem.  Would welcome any comments or advice from anyone who
> may have experienced a similar problem.  When I say "any" advice, I will not
> be receptive to any response including words such as idiot, dummy, meathead,
> etc.  You get the picture.  A preface of Your Excellence will guarantee my
> favorable acceptance and review.
>
> James Moore
> RILEY 37085 -2003 model.
>
>
>
>
>
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>
>
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