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8/3/2019 Bearings -Training Course 2002
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Bearings -Training course 2002
• Statistic's
• Recent service experience with standard thick shell main
bearings.
• Case story – L70MC/ Thin shell bearings/ Hydraulic trippel
jacks.
• New type measure equipment for journals and saddles.
• Cross head bearings – test with changed clearances, larger oil wedges and removal of the lead over layer.
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Bearings Training course 2002
• Statistics.– Number of reported damages to MC engines.
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Bearings Training course 2002
• Statistics.– Number of reported damages to MC engines.Position in
relation to previous graph.
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Bearings Training course 2002
• Statistics.– Number of reported damages to MC engines.
Graphic presentation of the positive influence by
the OLS type main bearing, reduced top clearance
and off-set / alignment procedure updates.
Fore: Main bearing # 1 & 2
Aft: Three aft most main bearings
Centre: Remaining main bearings
Alignment
procedure finalised
Flex-edge
introduced.New SL – Reduced
Top clearances
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Statistic:Reported main bearing damages S80-90MC-C.
The one reported
damage is believed to
be caused by a local
production mistake on
the bearing shell. The
damage was very small
and presumably caused
by a small hollow area
Percentage in relation to total number of main bearings in service = 0,89%
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Bearings Training course 2002
• Test of individual features – in this case ”flex edge”
The flex edge type were tested on a 8S60MC # 6 –
which had suffered 3 repeated damages – The
inspection after 6000 hours revealed good condition.
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Bearings Training course 2002
• ”Thick film” test main bearing – Features:
• Test of individual features – in this case ”flex edge”
The flex edge type were tested on a 8S60MC # 6 –
which had suffered 3 repeated damages – The
inspection after 2000 hours revealed good condition.
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Bearings - Training course 2002
• ” Flex edge bearings in service”
A s ia n P ro gre ssLL 919140
8S 80MCMIT 3804
M B N o .: 6 01-09-27 S in gapore
MignonLL 918925
8S 60MCHan 98464
M B no 6 . 01-
MignonLL 918925
8S 60MCHan 98464
MB no 6 .O pe n-up in sp ec tion
01-05-11 Gothenburg
Mignon
LL 918925
8S 60MC
Han 98464
MB no 6 .
O pe n-up in sp ec tion02 .04 .16 B remerhaven
LuxembourgLL917143
7S 80MCHA N97434
M B no 4 and no 7 . 02-01-05 Fos sur M er
Sonangol K izombaLL 920377
6S 70MCKor H506
M B no 2 and 7 02-01-15PhiladelphiaDelaware
Iria TapiasLL921275
6S 70MCHS D 99514
M B N O 2. 02-01-24 A lg eciras
Sonangol Luanda
LL 920376
6S 70MC
Kor H
M B N o 7
M B N o 2
02-02-06
02-02-28
Gibral tar
Fos sur Mer A lb em arle Is la ndLL905960
8S 60MCMIT 3276
M B no 6 02 .03 .18 A ntwerpen
A rto isLL923096
7S 80MCH it
M B no 8 02 .04 .14 R otterdam
I ran Semna nLL 917145
6S 70MCHS D 97459
M B no 7 02 .05 .01 M alta
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Bearings - Training course 2002• ” Flex edge bearings - Drawing ”
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Bearings - Training course 2002• Reduced top clearances – Service experience.
Vessel
LL. No.
Eng.Type
Maker
Date Bearing
No
TC MIN
/acc SL
Damaged
againDonQuijote
8S60MC Juni 98 4 0,15(Belowmin)
No
Boheme917656
8S60MC99.08.22 7, 9 X No
ChannelAliance912746
6S70MC 99.01.08 1 X No
CharlesIsland905962
8S60MC 99.06.02 No. 6(NHNdesign)
X No Clipper HaraldLL917306
6L50MC 99.05.18 7 X No
Clipper VikingLL917305
6L50MC 99.09.13 4 lejer X No
Colombia917507
6S70MC 99.05.12 7 X No EagleAugustaLl 904651
6S60MC 99.07.12 5 X No
Heng Chan917465
6S70MC 99.12.30 3 X No Knock Ann
904105
6S70MC 98.11.19 4 X No
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Bearings - Training course 2002• Reduced top clearances – Service experience.
KotaHarmuni
6S50MC 99.03.30 X Fax Infod.00.02.10
from builder,problemsolved byreducing topclearance in# 1,2&3.
Luxemburg 77S80MC 99.07.03 6 X No MareInternum 8S70MC
MK599.05.15
4,6 X No
MareThracium
8S70MCMK5
99.05.284,6 X Backoil
No
Marethracium915152
8S70MC M6Hyu
99.08.066 X No
Mattea913188
2x7S50MCML 0049and 0050
99.11.08 5,7 X No
Mignon918925
8S60MCKOR 98464
99.11.20 1,6,7,9 X No (- 6)
Peene Ore914979
7S80MCKor 96362
99.01.19 7 X No Picardie917144
7S80MCKOR097435
99.10.17 4,7 X No
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Bearings - Training course 2002• Reduced top clearances – Service experience.
Tai Shan917464
6S70MCHYUAA1068
99.11.06 6,7 X No Asakasan915768 6S70MCHYU A0967 00.06.26 1 X No BritishProgress918015
7S80MC 00.10.22 5 X No
ChristianeOldendorff
Ll. 912309
5S50MC 00.01.24 5 X No
Eric LD916922
6S70MC 00-03-178 2 X No Frank A.Shrontz916483
7S80MC 00.09.23 5 X No
Heng Shan
917465
6S70MC 00.02 3,4,5 X No Isere918877
6S50MC 00.02.17 1,2 X No Manon917972
8S60MC 00.02.8-12 1,6,7,9 X No Seine 6S50MC Marts 00 2,5 X No
YükselGüler 916098
1 X No
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Main bearings Training course 2002• Summery damage situation:
San
Francisco
Unit no when Where
# 2 damaged - replaced 2/10-01 USA
# 5,6 and 7(upper) found damaged, #5 and #7 replaced. 28/10-01 Melbourne
and Sydney
#6 Replaced 14/12-01 Melbourne
# 2 and # 5 – Repeated damage – Replaced.
# 4 found damaged and replaced
7-14/01-
02
USA
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Main bearings Training course 2002• Summery damage situation:
Samaria Unit no when Where
# 2 and # 5 (damaged) 22/9-2001 Singapore
#6 Inspected – Condition OK 22/9-01 Singapore
#5 Inspected – Hair cracks – scraped re-installed. 12/10-01 La Spezia
#4 found damaged and replaced – Saddle/house geometry
measured.
5/11-01 Melbourne
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Main bearings Training course 2002
• Findings – cause of damage: Small signs of light relative
movements suggesting that the
bearing house – not have been
fully ”compressed”. This is
supported by the loosening
pressure of 350-400 bar.
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Main bearings Training course 2002
• Findings – cause of damage:Measurement of
bearing house
geometry by
means of strain
gauge based
bridge and
proximeters.
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Main bearings Training course 2002
• Findings – cause of damage – Results of measurements :
Bearing cap dismounted
Bearing cap tightened 700 bar
Saddle in ”free” condition
Bearing house complete tightenedto 700 bar.
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If the hydraulic jacks
are not fully
compressed beforestarting the
tightening sequence –
Interference between
the piston and the
body may occur.
The result will be as
in this case that only
the upper jack will
provide extension of
the stud, thus tension
of the bearing house.
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Main bearings Training course 2002
• Conclusion - As per our Service report:
In- correct tightening of the bearing housings.
•The reason for this is believed to be hydraulic jacks not being fully
compressed prior to the start of the tightening sequence.
• The reason for not discovering the phenomenon should properly be found in
a consequently inadequate tightening with approx. 350-400 bars both during
machining of the bearing house and during assembly of the engine. This will
provide top clearances in accordance with the specified – but will result in a
inconsistent bearing housing geometry leading to a change in the ratio
between the top and side clearance.•Retightening to correct pressure/force will result in a decrease of the top
clearance as observed – but our investigations indicate that this change in
bearing house geometry may not have negative influence on the performance
of the bearings involved.
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Main bearings Training course 2002
• Conclusion - As per our Service report:
Main bearings – Repeated damages M/V San Francisco # 2 and #5 and
experienced damage in main bearing # 4 ( USA January 2002)
Main bearing No 2:
Inclined journal imprint – larger toward fore – Result”edge load toward fore”.
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Main bearings Training course 2002
• Conclusion - As per our Service report:
Main bearings – Repeated damages M/V San Francisco # 2 and #5 and
experienced damage in main bearing # 4 ( USA January 2002)
Main bearing No 2: Countermeasure.
Prior to the installation of the new lower shell in SanFrancisco the forward edge was relieved by manual
scraping to improve the situation – The inspection in
L.A revealed good condition. Light additional scraping
was made on the remaining line indicated by red arrow
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Main bearings Training course 2002
• Conclusion - As per our Service report:
Main bearings – Repeated damages M/V San Francisco # 2 and #5 and
experienced damage in main bearing # 4 ( USA January 2002)
Main bearing No 5 : Findings and countermeasure:
The new lower shell was similar to # 2 made with
corrective scraping on the forward edge
corresponding to the visual appearance on the
damaged bearing shell.
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Main bearings Training course 2002
• Conclusion - As per our Service report:
Main bearings – Repeated damages M/V San Francisco # 2 and #5 and
experienced damage in main bearing # 4 ( USA January 2002)
Main bearing No 4 : Findings and countermeasure:
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Main bearings Training course 2002
Countermeasures introduced to avoid similar situations in the
future:
• Service Letter has been issued – in order to further highlight the
importance of a correct use of the hydraulic jacks.
• Quality Specification has been issued intended to be used at the
engine builders to prevent wrong tightening prior to the
machining of the bearing houses.
• New updated Quality specification regarding ” Rectification of
main bearing saddles MC/C engines” have been issued.
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Main bearings Training course 2002
• Journal geometry – Verification :
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Bearings -Training course 2002
• Cross head bearings – Test with changed ratio to the oil –
wedges.
Wiped lead into the oil wedges – in this case however
insignificant amount.
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Bearings -Training course 2002
• Cross head bearings – Test oil –wedges.
Same unit as in the previous slide
– however oil-wedges enlarged
by hand scraping prior toinstallation.
Flattened wedges
2x standard length
– same depth
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Bearings -Training course 2002
• Cross head bearings test with all features: Enlarged
clearances, oil wedges, missing lead over layer, larger centre pads:
L60MC
Sameengine
as
previous
photos.
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Bearings -Training course 2002
• Cross head bearings test with all features: Enlarged
clearances, oil wedges, missing lead over layer, larger centre pads:
L35MC – AlSn40 – CPP Propeller.
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Bearings -Training course 2002
• Cross head bearings test with all features: Enlarged
clearances, oil wedges, missing lead over layer, larger centre pads:
L35MC – AlSn40 – CPP Propeller.