20/11/2017 15:11 GMT | Updated 20/11/2017 16:02 GMT

Mystery As Argentine Submarine With 44 On Board Goes Missing In South Atlantic

There's been no word from crew since Wednesday.

Fears are growing for an Argentine submarine with a 44-member crew which has not been heard from since Wednesday.

The ARA San Juan submarine was 432km off Argentina’s coast in the South Atlantic when it sent its last signal, navy spokesman Enrique Balbi said.

Satellite calls detected over the weekend during a search-and-rescue operation did not come from vessel, dashing hopes the crew were trying to make contact.

Marcos Brindicci / Reuters
A card for the crew of the missing submarine hangs on a fence at the Argentine Naval Base it sailed from 

The calls “did not correspond to the satellite phone of the submarine San Juan,” Balbi said.

More than a dozen boats and aircraft from Argentina, the United States, Britain, Chile and Brazil have joined the search effort, which has been complicated by waves of up to 30ft and winds reaching 40 knots.

The navy said an electrical outage on the diesel-electric-propelled vessel may have downed its communications, though protocol calls for submarines to surface if communication is lost.

Marcos Brindicci / Reuters
The ARA San Juan submarine was 432km off Argentina’s coast in the South Atlantic when it sent its last signal, a navy spokesman said 

Three boats left Mar del Plata on Saturday with radar detection probes and were following the path that the submarine would have taken to arrive at the base in reverse, Balbi said.

“Those probes allow the boats to sweep the ocean floor during their journey and try to make a record of the floor in three dimensions,” Balbi said.

The US Navy said its four aircraft were carrying a submarine rescue chamber designed during World War II that can reach a bottomed submarine at depths of 850 feet and rescue up to six people at a time. The chamber can seal over the submarine’s hatch to allow sailors to move between the vessels.

It said it also brought a remote-controlled vehicle that can be submerged and controlled from the surface. 

The clock is ticking for the crew, with former US Navy diver and submariner William Craig Reed telling CNN that while submarines of this size and class can stay at sea for around a month, “that doesn’t mean they have 30 days underwater.” 

He added: “It’s dependent upon the last time they actually recharged their batteries, how long ago they refreshed the air, what’s inside the machine. We just don’t know.” 

Handout . / Reuters
The ARA San Juan pictured in 2014 

The dramatic search has captivated the nation of 44 million, which recently mourned the loss of five citizens killed when a truck driver plowed through a bicycle path in New York City.

Crew members’ relatives gathered at the Mar del Plata naval base, where the submarine had once been expected to arrive around noon on Sunday from Ushuaia. However, it would not be unusual for storms to cause delays, Balbi said.

At the entrance of the base, locals hung signs with messages in support of the crew members and their families on a chain-link fence.

“Strength for Argentina. We trust in God. We are waiting for you,” read a message inscribed on a celestial blue-and-white Argentine flag hanging on the fence.

“Let’s go, men of steel. We are waiting for you at home,” read a message written on a picture of the submarine.

Argentine-born Pope Francis mentioned the missing vessel in his Sunday noon prayer.

“I also pray for the men of the crew of the Argentine military submarine which is missing,” the pontiff said.

The ARA San Juan was inaugurated in 1983, making it the newest of the three submarines in the navy’s fleet. Built in Germany, it underwent maintenance in 2008 in Argentina.

That maintenance included the replacement of its four diesel engines and its electric propeller engines, according to specialist publication Jane’s Sentinel.