[UB355]

Not water but a version of what is called AFFF. aqueous film fighting foam. It lays a vapor barrier on top of the fuel to seal in the vapors.

[dbalaska]

If you read up on KC-135s, they've had several engine revisions over time, but they've always been considered jet aircraft. The first version had turbo jet engines, while the latest models have turbofan engines, which most people generally think of a jet engines.