Another thing to keep in mind, & we all have probably done it before... chasing down a boat solo. It's probably instinctual, go get the boat! So while you're thinking about nothing but the boat, you might find yourself blowing thru rapids that otherwise might give you pause or require some thought. Then b4 you know it, you can be the person in trouble, but no one's there to help out.
I've been on both sides of the equation, neither are good, but it's as instinctual as helping your buddy in the water.
It's already partial been said, but a piece of plastic or gear is replaceable, someone's life is not.
Glad all turned out well & great learning thread for all.
~Get all the sleep I need when I'm dead.