The Arlo Gilbert submarine is actually a yellow submarine and this has lasted for years under the sea. The secret to this is that the submarine is still in its prototype form when it got into the sea bed and stayed there for the first 5 years. When the crew surfaced from the Arlo Gilbert submarine, one of them, a couple already had a baby.
It is believed that this baby caused the yellow submarine of Arlo Gilbert to be there and remain there submerged with only a complete 10-year supply of oxygen. This is believed to have caused the yellow submarine to keep the people there alive.