Also, remember that inertia is affected by velocity, which is increased by the falling unsprung weight (unless we paddle in a vacuum)

> This is not true. The mass of the contents of the kayak are coupled
> enough that their presence will significantly determine how much damage
> will happen to the hull on impact.

> I have hit things hard enough to wish I was loosely coupled,
> and I much to my regret I was not. It hurts. Me, and the boat. While
> I may have moved slightly on impact, I was by no means "loose"
> or "sprung".

> The reduced weight of a lightweight boat will do next to nothing
> to decrease the inertia when impacting an immovable object.

> Try kicking your boat as hard as you can. Do it empty and do
> it with someone sitting in it. Empty, it will go spinning and rolling
> away whether it is 30 or 40 pounds. With another 150 to 200 pounds
> in it, you will A: damage the boat or B: break your foot. The weight
> of the passenger and cargo are tightly coupled.