What Are Shackles and Swivels?
Small metal links that connect the anchor to the chain - proof that the whole ground tackle is only as strong as its smallest part.
A shackle is a U-shaped pinned connector that links the anchor to the chain. A swivel provides rotational freedom: it helps prevent the chain twisting up as the boat swings and stops the anchor getting turned the wrong way in the windlass. In a line carrying tonnes of load, the weakest link is often a poor-quality shackle.
The rule is simple: the connector must not be rated below the chain’s own breaking load; it is the stamped working load rating (WLL) that matters, not just a “suitable size”.
Annual five-minute check
Secure the pin: A shackle pin that has worked loose through vibration is the classic way to leave the anchor on the bottom; the pin should be secured with stainless wire (mousing).
Swivel fitment: A swivel that is fitted rigidly straight to the anchor eye can fail under side load; either fit a short shackle in between or choose a model designed to take side loading.
Galvanising life: If it has gone grey and is weeping rust, the fitting has done its time and should be checked alongside the chain on the same schedule.
Always keep a spare shackle and wire in the locker; the reason an anchor is lost in a bay is usually not major gear failure, but a small bit of neglect.