How hard was it to survive at sea?

In the earlier thread on Robert Hewitt surviving 75 hours at sea, some people thought it was nothing special as he had food, a wetsuit and the water was 20 degrees. In fact even suggested that most healthy adults could survive five days if they did not encounter hungry sharks.

But this story on the Dom Post makes it clear it is quite extraordinary, some calling it the stuff of legend. And Hewitt was already badly hallucinating and had drifted around 40 kms north before drifting back south again.