The first movie really did have a great script.

and only the first one. the second one had some gems…

it bothers me how nobody talks about how physically impossible this scene is…

tip canoe upside down, submerge, air gets trapped within, body weight of two people hold it down

im honestly not seeing the impossibility but id be glad to be enlightened

Personally I’m not sure they’d be heavy enough to do this

Plus they’d run out of air

Actually, objects appear to weigh less under water. Alse, you body exhales 98% of the oxygen you take in, making this completely possible.

I started doing the maths to see if that was possible. Halfway through calculating the forces I realized that if the weight of the boat + two people was enough to get that much air to stay underwater then the boat would instantly sink if they tried to ride it over the surface (Simple application of Archimedes’s Principle of flotation: Any floating object displaces its own weight of fluid). So, assuming this boat actually works as a boat, it’s not possible.

Then you could tell, underwater there’s more pressure which means air is compressed and takes less volume but they would still have to come from the surface to that depth so what I said above still applies.

For Oxygen, a quick search on Google tells me that they wouldn’t die of lack of Oxygen but CO2 poisoning (http://answers.google.com/answers/threadview/id/258239.html). I’ll make a rough estimation of the boat’s volume, it’s about 3m long and looks like a triangular prism about 1m wide and 50cm high, the volume is about 0.75m³ (26.486 cubic feet). According to the equation on the page I linked, they could last 0.2337h which is about 14min. Possible, but they would have to be quick (also the CO2 production rate in that equation is probably at rest so they would probably actually have even less time).