Only if the flow rate is high enough to defeat the buoyancy. Not guaranteed at all. Also, there was no indication what the geography is within the hole. Organi

Only if the flow rate is high enough to defeat the buoyancy. Not guaranteed at all. Also, there was no indication what the geography is within the hole. Organic material will eventually break down and waterlog enough to lose its buoyancy. Those ping pong balls and rumored car, though...