Turtle Shell (Helmet) should make the player fall underwater faster

The idea behind my suggestion is because of how turtle shells work.

Since a turtle's shell is very heavy (they also use it as protection since they are tough/hard, and the weight causes turtles to move slower), if the player was wearing a Turtle Shell on their head, it would only make sense that it would add a lot of weight. My idea is that, if the player is wearing a Turtle Shell on their head, they should fall down to the bottom of the water source blocks/ocean/lake (etc), faster.