Not-So-Trivial Questions – Practical Answers for Mooring and Towing
In the world of marine anchoring, each component plays a specific and crucial role. Two elements that are often confused—but are functionally distinct—are the standard shackle and the Type D shackle. Both can be part of the anchor-to-chain connection, but they differ in form, function, and usage.
The standard shackle—also known as a CS—is a metal U-shaped fitting with a welded pin that passes through the anchor's eye. Depending on the anchor model, it can be supplied in galvanized steel, painted steel, or stainless steel.
At Posidonia, all our anchors come equipped with a certified standard shackle, properly sized, tested, and approved together with the anchor itself. For this reason, the standard shackle is considered an integral part of the anchor, serving as the first link in the anchoring system.
The Type D shackle, also referred to as AS, is a robust D-shaped metal fitting with a removable pin, secured by a cotter pin or similar locking device. Its purpose is to safely connect the standard shackle of the anchor to the chain or to a rope with a thimble eye.
Like the standard shackle, the Type D shackle is available in galvanized, stainless steel, or painted versions, and comes in Grade 2 and Grade 3, certified by all major marine classification societies. It is compatible with stud-link chains.
- At the beginning of the chain: Connects the anchor’s standard shackle to components such as a swivel fore runner and a Kenter shackle, enabling rotational movement in the chain.
- At the end of the chain: Connects to a rope with a thimble (a closed metal loop) or to other system elements.
In many cases, the Type D shackle is considered part of the first or last section of the chain, matching its mechanical characteristics.
Swivel shackle offers a compact, efficient solution. This component allows chain rotation, replacing the entire setup of standard shackle + Type D shackle + swivel + Kenter link. It's particularly useful for vessels that require smooth, tangle-free anchoring in dynamic conditions.
