I was lead to believe a rattlesnake won't want to make contact with a human as he{she} could end up hurt and unable to hunt, so the warn any approaching danger with their rattles, now theres one swimming in the water, i take it the land had flooded and it was making its way to some safer ground, so it was getting tired and if fear of drowning then it might climb on to the boat if not, i would have said once it saw another danger of the two humans it would have swam away,
the one thing i don't understand is why did they hit it with the fishing rod, as most Americans seem carry guns why didn't they shoot it, and they were out in the outback, unless they where sitting in a pond in the city]
where they come across bears, coyote, mountain lions and even fellow humans
so is this going to upset someone, if it does then i apologize for it but even in the face of danger that creature has the right to live, and you don't kill it just because you might think it could bite you,