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Precis File
SHIP NAME: Sichem Aneline KEY: NUM. ENTRIES: 2
source TSB
type D
volume
material
dead
link http://www.bst-tsb.gc.ca/eng/rapports-reports/marine/2007/m07l0040/m07l0040.asp

Excellent TSB report, which should be required reading for anybody interested in tanker and ship safety.

Ship had four steering system failures between 2007-04-03 and 2007-04-26. After the first one on the 3rd, some repairs were made to the hydraulic control piping, and DNV said everything was fine. Two failures on 2007-04-11 while the ship was down bound, loaded with 7,781 tons of benzene, in the St.Lawrence resulted in her grounding just below Montreaa on soft bottom. She was refloated four days later, no hull damage. Two weeks after the DNV inspection, TSB found many minor defects in the steering control system which was overhauled.

But after the overhaul, the system again failed on 2007-04-26. The common factors in all the failure is that both steering pumps were on-line, and there was no alarm. TSB could not pinpoint the cause, but felt that there was an intermittant failure on the electrical side, leading to the two pumps working against each other. TSB noted that other ships using this system made by Fluidmecanica of Vigo had experienced similar problems.

Later the manufacturer rewired the control system, simply by-passing two relays with DMV approval and declared the problem fixed. See below.


source CTX
type C
volume
material
dead 0
link

This innocuous, minor grounding is replete with important lessons.

Despite the "fix", another steering system failure on this ship became public just 8 months later. See 20080101_001.

The ship had switched Class from BV to DNV on 2005-11-04. No maintenance records were available before then. The standard practice in marine tranportation is that whenever a ship changes owners --- or even managers --- the maintenance records disappear. In aircraft, it is a requirement that all maintenance records stay with the airplane.

The available (2006) maintenance records show no steering gear losses, but do show three instances of repairs without saying what prompted the repair. Only the most trusting would believe that the four failures in April 2007, were the only such failures; but we have no record. (One of the repairs involved replacing two hoses with over-length hoses, contrary to IACS requirements, but this repair were subsequently inspected and approved by DNV.)

TSB made a big and valid deal about the lack of maintenance records, recommending aircraft style rules to IMO, which recommendation as of late 2009 had gone no where.

TSB also recommended the Solas requirement that both pumps be on-line in tight navigational situations be modified. The Solas requirement is aimed at speeding up response, basically halving the lock to lock time from about 25 seconds to about 12, and eliminating the delay if one pump fails. But TSB points out with systems such as this ship's, having both pumps on line can create more problems than it solves.

The core problem here is not two pumps; but poorly designed and horribly unreliable systems. This is not just confined to the Fluidmecanica machinery. IACS which has far, far more failure data available to it than the public requires that a notice be posted near the steering control stand saying "Caution: In some circumstances when two power units are running simultaneously, the rudder may not respond to helm. If this happens, stop each pump in turn until control is regained." Can you imagine the FAA requiring a similar notice for two engine aircraft?

The Sichem Aneline was carrying 7,781 tons of highly toxic, highly volatile benzene. If she had hit another ship as the result of her steering problems, we could have had a big spill and or fireball, and probably no idea why. As it is, we know pretty much exactly what happened, but this information has been pretty much ignored by the regulatory system.