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The work performed by petitioners is included in the engine
manufacturer’s maintenance manuals. These procedures are routine
and recurring and necessary to maintain a towboat in good
operating condition. Petitioners’ towboats were in good working
order and operating condition when they were brought in to have
the above procedures performed.
Petitioners perform these procedures after a towboat has
operated for 25,000 to 35,000 hours. A representative towboat is
used about 8,000 hours per year so that the procedures are
performed on a towboat every 3 to 4 years. Petitioners select a
towboat for these procedures by utilizing a series of criteria.
First, they use a 25,000-hour guideline to screen towboats to
determine whether it is time to perform the procedures. Next,
for towboats that have accrued 25,000 to 30,000 hours of use
since the last procedure, wear on a piston’s compression ring is
measured for each engine and the towboat’s oil consumption
patterns are studied. Petitioners do not remove a towboat
engine’s power assemblies to measure the ring wear for each of
the pistons in the engine. These measurements are taken by
removing the “air box handhole covers”, positioning the pistons
so that they are accessible from the air box handholes, and using
a “feeler gauge” to take these measurements. If the ring wear
indicates that procedures involved are appropriate or if a
towboat appears to be consuming more oil than normal, the
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Last modified: May 25, 2011