Generally swivels are only really required when anchors spin (hydro-rotate) in the water on deployment and retrieval, said Ned Wood of Manson Anchors. Evidence of this would be when you hear the chain skipping on the gypsy.

What is a swivel anchor?

Swivels are used to attach an anchor to the chain with the purpose of preventing chain twisting as the boat moves around in the anchorage. ... Swivels are generally considered to be the weakest link between your anchor and the boat.

When should I replace my swivel anchor?

While there's no way to tell exactly how long each component should last, it's not uncommon to switch out heavily used anchor lines every 3-5 years. Chain generally lasts a little longer, but we do recommend checking the condition of the splice every year to ensure it's still holding correctly.