In article ,
Dave Smith writes:

There is a similar question about a boat full of iron ore sinking
lock. in a canal The water level does not change because floating
objects displace water equivalent to their weight.

Nope. The water level drops.

In the boat, the iron ore displaces a volume of water equivalent to its
weight. Once the ore sinks, it displaces only its own volume of water. As
water is significantly less dense than iron ore, the water level goes down.

You're confusing this puzzle with the one about floating ice cubes. Even Mr.
Wizard got that one wrong