Kim Jong Un was looking to celebrate North Korea's newest show of power when disaster struck.
He was at the launch ceremony for a new 5,000-tonne warship when it slid off its ramp, throwing it off-balance and damaging parts of its hull.
While the extent of the failure was dramatic, what was potentially more significant was the rare public admission of failure.
The story was carried by the tightly controlled North Korean state media, with Mr Kim describing the incident as a "serious accident and criminal act caused by absolute carelessness, irresponsibility and unscientific empiricism".
Here's what we know happened and how a failed ship launch might affect North Korea's military and nuclear ambitions.
What do we know about the ship?
The ship was set to be the country's second naval destroyer, with the first unveiled last month.
Experts said the first ship was North Korea's most advanced to date, with Mr Kim saying it was a critical step in achieving his goal of expanding the military's nuclear strike capabilities.
The vessel was named Choe Hyon, after a famed Korean guerilla fighter during the Japanese colonial period.
North Korean state media said the ship had been designed to carry weapons systems including nuclear-capable ballistic and cruise missiles.
South Korea's military said the damaged vessel was likely the same class of destroyer as the first and carried similar capabilities.
Spokesman Lee Sung Joon said satellite imagery showed the warship was still partly submerged in the water at the north-eastern port of Chongjin on Thursday.
It appeared that the ship had rolled on its side and was positioned diagonally from the dock.
Earlier satellite images showed indicated that North Korea was building a second destroyer at a shipyard in Chongjin.
South Korean officials also said it was likely the shipbuilding program was being supported by Russia, with ties deepening between the two countries.
Why admit failure?
Experts say the public admission of the incident is significant for a number of reasons but isn't necessarily new for Kim Jong Un.
North Korea expert at Oxford University, Edward Howell, told the ABC admissions of failure had been made about his five-year economic policy and also botched satellite launches in an attempt to differentiate himself from his father, Kim Jong Il.
Dr Howell said there was a domestic element of "naming and shaming" officials responsible for the incident, but it was also a message intended for the international community.
"This sends a clear message to South Korea and the US that North Korea isn't going to stop in trying to repair and strengthen its naval technology," Dr Howell said.
"We shouldn't treat this public admission as an admission of North Korean defeat."
Moon Keun-sik, a navy expert at Seoul’s Hanyang University, agreed.
"The reason why North Korea disclosed the incident is it wants to show it's speeding up the modernisation of its navy forces and expresses its confidence that it can eventually build a greater navy," Mr Moon told AP.
Dr Howell said Pyongyang had longstanding concerns about US and South Korean joint military drills, which it has described as being preparations for nuclear war.
He said it was a "clear message" to the South that it was advancing its naval capabilities, and that the country would continue moving toward its major goal.
"Kim Jong Un's ultimate aim is to gain defacto recognition as a nuclear-armed state, and the naval development is very much linked to that," he said.
"The whole point of having these large destroyers is that they are missile-capable."
If Pyongyang can get South Korea or the US to recognise its nuclear status, he said, it could call on those countries to stop engaging in military exercises, or possibly sign a treaty to end the Korean War.
"This means that the rationale for the US forces in South Korea goes out of the window, it's a long train of events," he said.
"It will be incredibly damaging if any of this [nuclear development] does go ahead."
What happens next?
Kim Jong Un has set a deadline of June to fix the stricken warship.
He has also called a meeting of the ruling Workers' Party slated for late June to address "irresponsible errors" by those responsible for the incident.
Edward Howell expected more rhetoric and weapons testing by Mr Kim and his Pyongyang regime in the near future.
He also expected efforts to build its nuclear program to continue.
"In my view North Korea will never give up its nuclear weapons and it has no intention of improving its delinquent behaviour," he said.
ABC/wires
