An anchor chain is the heavy links that hold a boat to its anchor. Pay out the anchor chain.
Its weight is what holds, since the chain must lie flat so the anchor is pulled sideways. You let out several times the depth of anchor chain, not just enough to reach the bottom.
1nounanchor chainThe heavy links that hold a boat to its anchor.
“The anchor chain ran out with a noise that woke the whole harbour.”
anchor chain is a chain.
Practised in Sea & Sailing