Just what do you find plausible? That a 500 year-old man and his sons took 100 years to build a boat? That a wooden boat that big would even float without coming apart? That any boat could be built big enough to hold two to fourteen of every animal on earth including birds and insects and all the food and water they would need for almost a year? Or do you find it plausible that there was enough water to cover the tallest mountains?
Doesn't end there either. You let all the animals which are prey for others off and they need to go breed like fuck for years before the carnivores get let loose. So you've got lions and tigers etc to feed for years on fuck knows what, whilst their regular dinners reestablish their herds. Even my daughter could work this issue out when she was 7. That if a lion ate attacked and killed an antelope just after they got off the ark, antelopes would go extinct and then what would the lions eat?
Play that out up and down the food chain, considering those creatures with highly specialised diets etc and it's pretty fucking obvious that someone didn't understand what they were talking about when they dreamt this shit up.
The whole stupid story is implausible, from start to finish. I can't believe there are adults with functioning brains who still consider it to be remotely achievable.
The Bible is full of interest. It has noble poetry in it; and some clever fables; and some blood-drenched history; and some good morals; and a wealth of obscenity; and upwards of a thousand lies.