What did Charles sturt hope or expect to find on his expeditions?

Charles Sturt's primary objective was always to find whether or not there was an inland sea in Australia. He followed the rivers of New South Wales in an attempt to determine whether they emptied into an inland sea as, unlike the rivers of other continents, they flowed away from the coast rather than towards it. This particular mystery was solved when he discovered that many of the rivers of NSW flowed into the Murray, which then emptied into the sea at the southern coast.

Sturt's final expedition, which was into the interior of Australia, was also his attempt to find an inland sea.