Don't believe it for a second.
If Rands philosophy was for a persons actions to coincide with personal gain, why then do the focus characters of Atlas Shrugged willingly destroy their own financal empires? Certainly such an action would be contrary to previous claims of Rands philosophy as it counters gains in income or power.
To a Randian Objectivist, mans moral purpose is dictated by his drive for personal happiness, and ownership of his self. Thus, if saving a person from drowning accomplishes that goal he would do it. Not because it would cause him increased earning or power potential.
Thus the extra marital affair between Dagny and Hank as well as the industrialists setting up a new society where they produce only for themsleves and not for financial gain.
Thus also why I don't think the question of the drowning man actually applies to Rand Objectivism, as I can't fathom a person who wouldn't accomplish personal happiness in the saving of another persons life. Now if we were to switch out the the literal and instead make the person "drowing" in debt. A Randian Objectivists wouldn't save this person by solvling their financial problems as that would keep the person from "owning themselves" by becoming indebted to another person for correcting their own problems.
Visit the Rand Institute. Learn for yourself. It's the Rand way.
"I KICKED BURNING TERRORIST SO HARD IN BALLS THAT I TORE A TENDON" - Alex McIlveen