[Sentoa] Heat exchanger

[Steve Cuff]

Absolutely no questions about it.  Gremlins and evil spirits.  They run
around my boat too and bite me in the ass on occasion.  Good luck.

________________________________

From: sentoa-bounces+scuff=calex.com at lists.samurai.com
[mailto:sentoa-bounces+scuff=calex.com at lists.samurai.com] On Behalf Of
tugs4me at comcast.net
Sent: Monday, September 14, 2009 6:26 PM
To: South East Nordic Tugs Owners' Association (SENTOA)
Subject: [Sentoa] Heat exchanger


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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