socom wrote:Forget fire; even a coin-sized chunk of sodium thrown into water will explode, and larger chunks will explode spectacularly. The biggest "sodium party" I've ever heard of involved a four-kilogram block which exploded with the force of a depth charge (you can read about it on Theodore Gray's WPT website; not sure what the forum policy is for posting links but it's easy to google).
With a boat-sized chunk of sodium an explosion would be inevitable, and it would be massive. I wouldn't expect the cruise to last more than a few seconds - expect an earth-shaking explosion throwing chunks of the boat every which way. These would then trigger more explosions as they splashed down hundreds of meters from the original blast site. Bottom line is, you *really* wouldn't want to be in (or for that matter, anywhere near) the boat.
When my high school chemistry teacher demonstrated this, a one-gram piece of sodium SHATTERED the entire beaker into coin-sized fragments.