[BITList] Fwd: [BIship] Rajula crankshaft failure

[Michael Feltham]

Begin forwarded message:

From: "Smythe" <Anthony at Smythe1933.fsnet.co.uk>
Date: 19 January 2009 17:08:46 GMT
To: <BIship at yahoogroups.com>
Subject: [BIship] Rajula crankshaft failure
Reply-To: BIship at yahoogroups.com

This incident occured on leaving Penang on 26th March 1964. The  
starboard main engine crankshaft fractured through the main journal  
immediately forward of the forward
I.P. crank web. Rajula was built in 1926, and was thus 38 years old at  
the time. The Chief Engineer said in one of his reports that in his  
opinion that there had been an inherent fault in the manufacture of  
the shaft.

However, the metallurgical report from Lloyds Crawley dated 23rd July  
1964 stated quite categorically that failure had occured at a sharply  
angled step in the journal, and that no detrimental internal forging  
defects had existed prior to the failure, i.e. the fault lay in the  
design of the crankshaft and not in its manufacture.

The following are extracts from the Lloyds report:

"On drawing the fractured part from the crank web it was noted that  
the diameter of the journal was greater inside the web, the shaft  
being sharply stepped flush with the crank web face and coincident  
with the origin of the fracture. "..." The diameter of the journal  
within the shrink was approx. 13.5" while that of the portion outside  
the shrink had been reduced to approx. 13.2". Examination of the  
mating halves of the fracture showed that the form of the step had  
been an acute right angle. A fatigue crack had commenced at the root  
of the step and had propagated slowly and under relatively low cyclic  
stress..."...." It was clear that failure had occurred due to combined  
torsional and bending fatigue originating at a sharply angled step in  
the journal"....." It is not known at what stage in the life of the  
crankshaft the step in the journal was machined, but the nature of the  
fracture indicated a slow crack propagation under a relatively low  
level of cyclic stress. "... " ...." there was no evidence to indicate  
that any detrimental internal forging defects had existed prior to the  
failure "

In the light of the Lloyds report,  it would appear that BI would have  
had no grounds for blaming Barclay Curle for an inherent manufacturing  
fault in the original casting.

I'm afraid that I cannot recall if Barclays had a spare crankshaft -  
can anyone else recall how the repair was made? I remember that R.T.  
( Russell ) Smith was 2/E/O on board at the time of the incident.

Tony Smythe

[Non-text portions of this message have been removed]


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