Indeed, rust is the key.
In the [former] Soviet Union, tanks and other armoured vehicles were regularly swallowed up by rivers and bogs, but the freezing temperatures in that part of the world slowed decomposition by an amazing degree, which is why they keep pulling them out in "restorable" condition. Even then they're pretty bad - just look at the Canadian Valentine at the Canadian War Museum which came from a bog in Russia.
The Pacific theatre is characterised by warm weather and salt water/air - as "Lendlease" said, say no more.
BTW "Lendlease", do you have a real name?
