At times, inclement weather has caused difficulties.
This is especially true in an unprotected harbor where
the water roughness or groundswells have had an effect
on the movement of the ship at the pier. Therefore, to
facilitate the changeout, the ship must be pierside and
should be inboard of any other ship(s) present.
Sometimes, floating cranes have been used, but the
evolution was still hampered by the elements.
Tenderside changeouts have problems of a different
nature. The tender is a stationary platform. The ship
must be moved and positioned around the tender to help
the crane service. The SSE containers, when stored on
the tender and within reach of the crane, were on the 03
or 04 level. This made travel to and from the containers
Horizontal Rail Systems
The horizontal rail systems also have had problems.
Some of these problems are attributed to a lack of
inspection before use.
To ensure safe and proper handling of the engine
and/or components by the crane operator, have the ship
ballasted to remove any listing.
Dry trunnion bearings on rail stanchions are
difficult to turn. This is especially true if the adjustment
ring holes have been elongated. Therefore, a grease
lubricant (MLG-G-10924 or equivalent) should be used
to lubricate the adjustment ring.
The horizontal rail flanges, when not properly
lined up, will make the gas generator separation
hazardous. Misaligned rail flanges may cause the gas
generator position to shift and possibly damage the
C-sump air seals. On mating up gas generator to power
turbine, the No. 6 bearing cage can be damaged when
the front-frame lift fixture roller crosses the forward
flange in the rail. This makes the gas generator shift
The adjustable rollers on the lift fixtures are
susceptible to corrosion. Corrosion may cause the roller
to jam into one position.
If not properly lubricated
before use, the adjustable rollers on the lift fixtures are
capable of freezing up. This makes it impossible to
center the engine.
When not properly serviced and filled with
cylinder oil, the hydraulic support mechanism for the
compressor front frame will not permit the jack to be
extended far enough to support the front frame for
removal of the support pins.
Ensure all feeder rail sections are installed and
aligned before checking the travel of the system with a
If a bearing failure necessitates an engine
changeout, a complete flushing of the lube oil system is
Tag and Bagging Practices
There is evidence that tagging and bagging practices
on engine changeouts have not been followed to the
letter. This costs time during reassembly. Proper
identification is a valuable asset when the new engine is
reassembled in place. Lost and broken bolts, in some
cases, do not exist as onboard spares. Therefore, you
need to exercise care in disassembling and handling.
Once bags have been filled and identified, place them in
a secure place until they are required for the reassembly.
Replacement engines, when received, may not be
complete with all the fittings and adapters necessary for
connection. In some cases, a replaced engine was in the
container and heading for the supply depot before this
discovery was made. This caused additional time to be
wasted reopening the container and resealing it after the
parts or items were removed. Time has also been lost
when the replacement engines turbine midframe flange
was improperly clocked and another engine had to be
brought to the changeout site.
Mark the location of the silencer hold-down
brackets before removal. Proper marking makes it
much easier to reinstall the brackets and silencers.
Review QA requirements of Combined Forces
Afloat Quality Assurance Manual, COMNAVSUR-
FLANTINST 5090.lA and COMNAVSURFPACINST
4855.22, for level A repairs.
GTG ENGINE CHANGEOUT
GTG engine changeout procedures are described in
detail in the technical manuals, Model 104 Gas Turbine
Generator Set, volume 2, and Model 139 Gas Turbine