Dec 102009

image Atlanship, owner of the 33,000 gt fruit juice carrier Orange Sun, should provide its officers with training in the principles of bridge resource management that encourage and emphasize correct and unambiguous communication, information management, role responsibility, and contingency planning, says the US National Transportation Safety Board report into the vessel’s collision with the non-self propelled 61 metre dredger New York in Newark Bay, New Jersey.

image The National Transportation Safety Board, NTSB, identified the actions of the bridge team leading up to the incident as the primary safety issue in the Orange Sun accident. It is noteworthy that the NTSB includes pilots, if present, in its definition of a bridge team, an inclusion not accepted by other US authorities. In this case the bridge team consisted of the pilot, the master, and the navigational crew.

Says the NTSB: “The probable cause of the allision of the Orange Sun with the dredge New York was the master’s failure to appropriately use bridge resource management and to communicate; specifically, to familiarize his bridge crew with and inform the pilot of the vessel’s occasional tendency to sheer, a characteristic that he had personally experienced. Contributing to the accident were the inappropriate starboard rudder image movements made by both the helmsman and the master, which interfered with the pilot’s ability to take appropriate action to prevent the allision. Also contributing was the second officer’s failure to accomplish his primary duty as officer of the watch, which was to properly monitor the helmsman.”

Poor  master-pilot exchange, communications and passage planning are so familiar in such incidents as to be predictive. MAC would also highlight issued concerned with the use of Becker rudders and controllable pitch propellers in such circumstances.

The New Jersey Maritime Pilot and Docking Commission report into the same incident reproduces an interview with the Orange Sun master that is very instructive:

“Answer‐“That’s right. And plus additionally, the pilot, I would say doesn’t know enough about this combination of Becker rudder and variable pitch that he would not rapidly slow down the engine and giving order to starboard and the close quarter with the dredge, which I as a master in that moment could not explain it to him….”

With this kind of rudder the ship was, very fast responding”

Question‐ “Did you tell him [pilot] that vessel responded quickly to small ruder orders?”
Answer‐ “” I do not need to tell this to the pilot [sic] has 57 years old and he is a  New York pilot who has worked with the Becker rudder and he has to know what Becker rudder means and what means variable pitch. I’m not here to teach the pilot what the rudder means.”

The master had made an assumption about what the pilot needed to know, an error commonly made. An old saying applies: “Never assume an expert knows what he is doing”. If the pilot had been given appropriate information about the vessel’s handling the incident might have been avoided.

With conventional propellers,with blades at a fixed pitch, the vessel’s speed through the water is altered by changing the speed of the propeller’s rotation, RPM. Controllable pitch propellers, as the name suggests, have blades with pitches that are variable. The RPM is constant and speed is adjusted by varying the angle of the blades.

An issue with CPPs is that as the angle of the blades, the pitch, approaches the plane of rotation the propeller becomes little more than a metal disc shielding the rudder from the flow of water needed to maintain manoeuvrability and creates turbulence which makes the rudder ineffective.

Because of this phenomenon it is unwise to reduce speed rapidly while turning the rudder. Speed should be progressively reduced.

NTSB Report Orange Sun

New Jersey Maritime Pilot and Docking Commission report

See also:

The Case Of The Confused Pilot


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