Choosing the Right Shackle
Why It’s More Important Than You Think
Shackles might seem like small pieces of gear, but in lifting and rigging, they carry a huge responsibility. They're the link between your load and the rest of your rigging setup, and if they fail, the whole operation can go sideways fast.
That’s why getting the shackle size right is non-negotiable. You need one that can handle the tension in your lift without getting overstressed or deformed, especially when dealing with angled loads or multi-leg configurations.
What “Shackle Size” Really Means
When we talk about shackle size, we’re mostly referring to the diameter of the body, whether it’s a bow or D-type shackle. That size directly affects the Working Load Limit (WLL), which is how much force that shackle can safely take.
But size isn’t the only factor. Material grade, shackle design, and which standards it’s certified under also play a role in its safe use.
How to Choose the Right Shackle Size
Here’s what you need to factor in when picking the correct shackle:
- Total load weight
- Number of lift points
- Load distribution (even or uneven)
- Rigging angles
- Required safety factor based on your standards
In angled lifts, especially with bridle or multi-leg setups—the tension on each shackle can be way more than you’d expect. That’s where the math comes in.
The Basic Calculation (Don’t Worry—It’s Straightforward)
Let’s say you’re using a two-leg sling. You can estimate the tension per leg like this:
Once you have that tension number, you’ll want to choose a shackle with a WLL that exceeds the calculated tension x Safety factor.
Also make sure the pin size, body diameter, and opening can accommodate your slings or hardware. Tight fits or forced connections? That’s a no-go.
Tips for Picking the Right Shackle
- Use bow shackles for multi-leg lifts, they give you more flexibility.
- D shackles are best for straight-line pulls.
- Go high-grade if you need more capacity without increasing size.
- Watch your angles—side loading can reduce a shackle’s WLL fast.
- Stick with certified gear from known names like Crosby, Green Pin, or GN Rope.
Don't Cut Corners on Compliance
The right shackle needs to do more than just hold weight, it has to meet the standards for your industry or region. Make sure it checks the boxes for:
- EN 13889 / DNV-ST-N001
- ISO 2415
- LOLER (if you're working in the UK)
Using a calculator or sizing tool that follows these standards helps you avoid risks and stay compliant.
Not Sure What Size You Need? We’ve Got You.
If you're dealing with tricky lifting angles, unusual rigging setups, or just want peace of mind, our rigging team is here to help. We’ll work with you to:
- Run the numbers
- Recommend the right shackle type and size
- Source certified shackles from brands you trust
Give us a call or send a message, and let’s make sure your gear is just as solid as your lift plan.
