BALLAST

2001, bronze / riverstone, 21"h x9"w x6"d

private collection

bal·last /'bal?st/
verb; 

give stability to (a ship) by putting a heavy substance in its bilge.
"the vessel has been ballasted to give the necessary floating stability"

noun
heavy material, such as gravel, sand, iron, or lead, placed low in a vessel to improve its stability.
"the hull had insufficient ballast"