A group of Darwin stevedores are lucky to be alive after a crane unloading concrete ingredients failed.
It is believed the Han Jin Brisbane - a Korean flagged ship - was unloading clinker when the brakes on the crane's boom failed, sending the bucket into a free-fall into the cargo hold of the ship.
Nobody was injured.
Australian Maritime Safety Authority (AMSA) spokesman Mal Larson said the ship had come from New Zealand and was performing a side-shore grab when the incident occurred at East Arm Wharf last Sunday.
It is believed the wharfies worked for P&O Automotive and General Stevedores.
Maritime Union of Australia NT organiser Thomas Mayor said the crane's pilot did well to keep it away from the workers.
"The bucket was over the wharf and about to drop the load when he said he heard the crane making strange noises," he said.
"That was when he stopped, and brought the bucket back over the bow of the ship."
Mr Mayor said the pilot then called his co-workers over to discuss the problem.
"Then the boom just gave way, and this fully laden bucket of clinker - which weighs tons, free-fell."
The ship has since sailed.
On Tuesday, the container crane also ploughed into the raised boom of a crawler crane about 11am.
The corporation operator is believed to have told his bosses that he didn't see the crawler crane until he hit it, badly damaging cables on the smaller crane.
"The boom did not break, which prevented further damage," a source said.
"If the boom had broken, it could have come down on anyone nearby."
Two ships - one with live cattle and the other with cement products, possibly the same ship involved in this latest drama - were unloading at East Arm at the time.