MAN B&W Diesel A/S
Service Letter SL00-377/CEE
March 2000
Engine Room Safety
Action Code: IMMEDIATELY
Dear Sirs
Recently a crankcase explosion was experienced on a large bore MC engine due to a
main bearing failure.
We have investigated the very few incidents of crankcase explosions on MC engines
and, according to our findings, no such crankcase explosion has earlier been initiated
by a main bearing failure.
We have additionally been in contact with some of the classification societies, and
their statistics also show that the probability of a crankcase explosion is very small.
Safety has our highest priority and, even though the probability is small, we would like
to emphasise the prevailing MAN B&W inspection instructions and recommendations:
1. Whenever the crankcase is entered (minimum every 2-3 months) the oil pan is, as
a matter of routine, to be inspected for possible bearing material fragments. If such
metal fragments are found, the origin must be traced, and the bearing concerned
must be replaced by a spare.
The lube oil filter also has to be checked for possible bearing metal debris. See the
enclosed pages 702.01/02 from the Operation Instruction Manual.
HEAD OFFICE (& Postal address) DIESEL SERVICE PRODUCTION FORWARDING MAN B&W Diesel A/S
Teglholmsgade 41 Teglholmsgade 41 Teglholmsgade 35 Teglholmsgade 35 Denmark
DK-2450 Copenhagen SV DK-2450 Copenhagen SV DK-2450 Copenhagen SV DK-2450 Copenhagen SV Reg.No.: 24 231
Telephone: +45 33 85 11 00 Telephone: +45 33 85 11 00 Telephone: +45 33 85 11 00 Telephone: +45 33 85 11 00
Telex: 16592 manbw dk Telex: 31197 manbw dk Telex: 19023 manfw dk Telex: 19023 manfw dk
Telefax: +45 33 85 10 30 Telefax: +45 33 85 10 49 Telex: 19042 manfw dk Telex: 19042 manfw dk
E-mail: manbw@manbw.dk E-mail: diesel-service@manbw.dk Telefax: +45 33 85 10 17 Telefax: +45 33 85 10 16
http://www.manbw.dk E-mail: manufacturing/copenhagen@manbw.dk
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2. The oil mist detector, as recommended in our Service Letter SL90-262 dated
March 1990, should always be coupled to the engine safety system. We
emphasise that an alarm from the oil mist detector should provide an automatic
slow down, subject to maximum 6 seconds’ delay after an alarm has been given.
The automatic slow down must bring the engine rpm down to the pre-set value of
40% of normal mcr rpm, overriding a possible load reduction programme.
We realise that a number of engines, usually with main engine driven generators, are
provided with a manual slow down system. We strongly recommend that this should,
at the earliest opportunity, be changed to automatic slow down as follows:
A) The oil mist alarm should immediately cause the engine rpm to be
reduced to the lowest possible rpm necessary for the shaft generator to
stay connected to the grid.
B) An auxiliary engine should be started automatically and, as soon as this
has been connected to the grid, the main engine rpm should be
reduced to the slow down level of 40% of normal mcr rpm.
The time from the alarm is given to the slow down is activated should be as
short as possible and in any event less than 1 minute.
We furthermore refer to the enclosed pages 704.04, 05, and 06 from the Operation
Instruction Manual.
Yours faithfully,
MAN B&W Diesel A/S
Carl-Erik Egeberg Uffe Mikkelsen
Enclosures
