"Extremely robust", he tweeted Saturday. He claims that two divers will be able to carry the creation, and its size will allow it to fit through narrow gaps to navigate the cave system.
He said it would then take 17 hours to fly it to Thailand.
Narongsak said the healthiest have been taken out first, and the next phase of the operation would start in 10-20 hours.
The Thai Government said Mr Musk's team could help the rescue operation with location tracking, water pumping or battery power.
So far, the mission to save the team has proved complex and extremely unsafe. Proposing the plan via Twitter earlier today, it emerged that engineers from Space X and The Boring Company will offer their assistance to the ongoing local efforts. Shortly before 8 p.m., the SEALs reported on their official Facebook page that four had been rescued.
Thanasarn Narue-sataporn, a medical doctor with experience in rescuing people hit by natural disasters, including the last Nepal quake, said the cave's floodwater level is most crucial so authorities have to closely watch the situation around the clock and make their rescue decision in a timely manner.More news: China warns United States "opening fire" on world with tariff threats
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The ambulances were seen Sunday evening, but it was unclear who was inside them.
He added: "They can not decide how many of them will be able to come out for the first operation".
"There are probably many complexities that are hard to appreciate without being there in person", Musk wrote.
Representatives for Elon Musk are in talks with Thai authorities about aiding in the rescue of a boys' soccer team stuck in a cave. That's the name of the young boys' team. "They are now at the field hospital near the cave", Tossathep Boonthong, chief of the health department in Chiang Rai in northern Thailand, told Reuters.
Chaiyaporn Siripornpaiboon, a cave expert at the Department of Mineral Resources, told The Nation that the cave's floodwater level has become the most crucial factor in determining which option would be the most appropriate to rescue the stranded footballers.
Conditions are "perfect" to stage an evacuation in the coming days before fresh rains and a possible rise in carbon dioxide further imperil the group, Chiang Rai Governor Narongsak Osottanakorn said. They were found in the cave on Monday, after spending nine days trapped underground.
Reuters is reporting that at least two boys are out of the cave. Efforts to rescue them are hampered by narrow passageways and rising waters in the cave system. The team has been pushed back deeper into the cave, and their path out now includes swimming through narrow and unsafe passageways. But the expected heavy rains raise the risk of increased flooding and restricted access. The hand-written letters from the boys soccer team, ages 11-16, were filled with love and hope.