New Zealand sports broadcaster Miles Davis says bad weather is making the rescue mission almost impossible for his Navy diver son searching for the missing Argentinian submarine.
William Davis is on board the British polar explorer the HMS Protector, which was on its way to Antarctica when it was called back to join the search for the ARA San Juan.
The old submarine, built in 1984, has been missing for five days in rough seas with 44 people on board.
Miles Davis says his son has told him that "the rough seas are making it hard to locate anything and the forecast is not expected to clear for a couple of days".
Rescue aircraft and vessels have ramped up the search after a series of apparent attempted distress calls yesterday raised hopes they may be alive.
The Argentinian Navy was unable to confirm that the seven attempted calls originated from the submarine. "The communications are so short and the signal so low," spokesman Enrique Balbi said.
The Navy said there was enough food and air supply on board for the crew to survive for up to two weeks - but if some disaster has happened, that may not count for anything.
Miles Davis said his son has told him the mood on board the British Navy ship is "worried but trying to stay positive".
He added while there has been a fraught military relationship in the past between Argentina and Britain his son William says " they are neither British nor Argentinian sailors but a 'nautical family' and those involved in the rescue operation will do everything they can to try to find them".