The commission's report also found it was very likely that the person in charge of a short-staffed forward mooring team was unable to safely carry out the job of supervisor while also operating the winch.
The team had been reduced from four to three after a cadet left the crew earlier.
The report said two metal bars running across the winch should have been removed immediately after the equipment was fitted to the ship in 2008. The bars were only intended to support the assembly during transport and align it while it was installed.
With the bars still in place, there was very little clearance for the mooring rope drawn onto the winch drums.
The commission said it had last month recommended to the winch manufacturer, MacGregor Germany, that it ensure other operators using the winch had removed the bars.
MacGregor Germany undertook to contact its customers before the end of June, and report back.
The commission also found that the risk assessment for mooring and unmooring operations on the Singaporean-flagged container ship had not complied with the operator's safety management systems.
The operator had now overhauled mooring operation procedures in the rest of the fleet, the report said.
The commission said one of the key lessons from the accident was that unmooring operations were as dangerous as mooring operations, and crews should ensure there were always enough people to do them safely.
It said equipment must be installed and operated as intended by the manufacturer, and that crew members in a supervisory role should be observers and "not attempt to carry out an operational role".
The commission also said that risk assessments were only effective if control measures were put in place to mitigate the risks identified.
