Well it must have been quite a voyage. If the ship picked up Richard in the Canary Islands (which are in the Atlantic just off the northwest coast of Africa) they made a hell of a trip around the horn of Africa and out into the Pacific
I'm with you, if the black Rock was going to America, it was very ''LOST''
I think you're misreading the intent of this quote. He was saying that if they were headed to Australia, they are way off.
Think about it: from Europe to the Canary Islands to the New World is a straightforward journey across a single ocean. It would be a trip to Australia that would take them around the Horn of Africa.
Besides, the first mate specifically stated that the New World was the destination, and nobody pays for a condemned man just to take him from the gallows to a penal colony.
They were headed to America to mine.