Lessons learned
The Nautical Institute issued new Mars Report with a focus on safety critical equipment. Safety critical systems must be designed and arranged to be straightforward and intuitive, with safeguards to minimise human error. Crew members must be familiarised with all aspects of the operation of safety critical equipment. That includes steering gear control systems.
The Incident
As the vessel made way in restricted waters, the helmsman was atthe main console using the wheel to steer the vessel in full follow-up(FU) mode. While on a course over-the-ground of 221 with the rudderamidship, an alarm light on the steering control alarm panel lit upand an audible alarm sounded on the bridge.
The chief engineer, whowas on the bridge, asked the OOW what the alarm was, and the OOWresponded that it was the autopilot override alarm. Shortly after thisexchange, the vessel started to veer to port, towards the south side ofthe river, and the helmsman reported that the helm was not responding.
After the steering had been switched to non-follow-up (NFU) mode,the OOW, chief engineer, and helmsman each tried to use the NFUtiller switch on the right-hand control panel to move the rudder, butthe rudder did not respond. They then tried toggling between steeringmodes using the switches on this same control panel, but the rudderstill did not respond.
The Master arrived on the bridge shortly after and also attempted toactuate the rudder using the NFU tiller switch on the right-hand controlpanel, but to no effect. He then ordered the OOW and the bosun to theforward mooring station for an emergency anchoring. Although theanchor was dropped soon afterward, the vessel nonetheless groundedon the SW side of the river.
On the centre console panel there is also a short black ‘override’joystick that can be used to steer the vessel (NFU mode); however, on this vessel, it was not the practice to use this joystick. The joystick doesnot have an identification label, nor does it have a protective coveringor any other locking feature to prevent accidental activation. Onlya light touch of this override joystick is necessary to activate it andgive steering control to the joystick while disabling all other meansof steering in use.
To reactivate the other means of steering afterthe override joystick has been activated, an operator must press theoverride reset button on the steering gear alarm panel, which resets thesteering control system to its initial condition.
The official investigation found that, among other things:
Other lessons learned
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In many accident reports where FU steering is lost,crew are not familiar enough with their steering systems and NFU is leftuntried. In this instance, the bridge team had the right reflex to try theNFU but not the correct joystick. The only NFU that could have savedthem was the override joystick on the centre panel the one they didnttry. Unfamiliarity with the equipment and lack of identification werethe primary contributing factors. The fact that the override joystick wasunprotected could also be viewed as an unsafe condition.
Source: Mars Reports/ The Nautical Institute
