But on the rising tide mid morning, the vessel showed signs of starting to drift and the anchors were straining to hold it.
Reports suggested one propeller was lying on the beach.
The 97m-long barge only made its maiden trip to Westport on August 14, bringing hopes of a new shipping era on the West Coast.
It had been waiting off Westport for days waiting for conditions to ease for re-entry into port, but in rough seas early yesterday the vessel dragged its anchor and came aground at Carters Beach in the pitch dark, lights ablaze and with the 11-man crew still aboard.
No one was injured.
At low tide it is completely beached immediately in front of the Westport golf course, surrounded by flat sand.
Diggers created anchor points yesterday to try to hold her in place.
The grounding drew hundreds of people to the beach to view the spectacle yesterday, and by low tide mid-afternoon they were able to touch the hull.
Maritime New Zealand has taken charge of the incident, and so today everyone from the West Coast Regional Council to the Port of Taranaki, which is sending a specialist tug, refused to comment.
Westland Mineral Sands Ltd said in a brief statement at noon that a specialist recovery team it had engaged arrived in Westport last night.
The crew remained safely on board and additional food supplies would be delivered to them later today.
"We have engaged an independent expert to conduct a thorough investigation to help us understand how this incident occurred," the barge owners said.
Auckland salvage company Total Marine says pulling the barge off the beach could be difficult.
"With my experience and what I have been told, you are going to need a fair sort of pull and a large tug, possibly three tug boats," director Brent Shipman said.
"With it being stranded on the beach you are going to need some good water around the barge and probably want a large spring tide. Whether some machinery can help push while the tugs are pulling, but you are going to need some serious horsepower, that's for sure."
Buller Mayor Jamie Cleine said Maritime NZ was treating it as a national scale event.
"It enables them to unlock resource and expertise. My understanding is, they working on what the plan is — then will get approved with our harbourmaster and WMS (Westland Mineral Sands). They are clearly going to need tugs and resource from out of district, which will take some time."
Mr Cleine said there was a low risk of the barge breaking up as it was a nice safe beach, away from rocks and it was not leaking.
However, it was "very well planted".
He confirmed yesterday the Manahau had been sitting offshore for a few days waiting for suitable conditions to come into port, and that would be part of the investigation.
Residents at Marine Parade at Carters Beach got quite a view when they got up early yesterday to watch the All Blacks game in the early hours.
"I saw it beach about 1am (yesterday), I could see the lights. The sea was quite rough, but not that bad," Richard Dellaca said.
Diners at Donaldos Cafe on Saturday evening saw the lights of the barge in the distance out on the ocean.
They woke the next morning to see it grounded on the sand close to shore.
Blenheim visitor Rochell Warbuton could not believe her eyes: "Wow — it's amazing to see."
Chrissy Alfeld, who along with her husband Carl run the Carters Beach Top 10 Holiday Park, told Stuff they called emergency services when they first saw the Manahau in trouble.
"The barge was floating down the beach with searchlights on trying to find the shore," she said.
"We put the headlights of our car on so they could see the beach."
A Maritime Incident Response Team has been set up in Westport, and is being supported by other staff around the country.
Maritime NZ's incident controller Blair Simmons says the key priority is to stabilise the vessel.
"Diggers have been on the beach, creating anchor points to lock the vessel in place. This stops it from potentially drifting towards rocks at high tide," Mr Simmons said.
"Re-floating the vessel will be a delicate operation, and we will closely review any plans being put in place by the operator."
Westland Mineral Sands said today the Manahau was a fully certified vessel, classified for New Zealand operation by Maritime NZ.
The last boat to go aground at Carters Beach was in 1909.
- Laura Mills, Paul McBride and Lisa Gregory
