The stainless steel shackles we use on Harken® blocks are available separately. Harken forged stainless steel shackles are polished to a high luster and are stamped with the screw pin diameter. The breaking strengths shown are derived from weights supported by 80% of the length of the shackle pin, similar to the length spanned by an appropriate block's headpost.
"D" shackles are the most common type of shackle. They are best suited for aligned attachment points.
High Resistance "D" Shackles
High-Resistance (HR) shackles are forged in 17-4PH stainless steel to handle high loads. They have an "HR" imprint for easy identification.
Long shackles have a similar shape to "D" shackles but are proportionally longer for their width.
Large Open Shackles
Large open shackles have a similar shape to "D" shackles but are proportionally wider for their length. They have a smaller maximum working load due to the long pin length.
Bow shackles are best for multidirectional loads. Their large interior opening allows plenty of articulation especially when attached to a round bail.
Shallow Bow Shackles
Bow shackles are best for multidirectional loads. Shallow bow shackles are proportionally wider for their length than regular bow shackles.
Twist shackles are forged with a 90-degree twist so the two attachment points can be perpendicular without torquing.
Captive Halyard Shackles
These shackles have a secondary pin to keep the shackle permanently secured to the halyard and in the correct orientation.