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Professional Shackles - Marine & Rigging Hardware

Bow Shackles (Anchor Shackles)

The most versatile shackle type, featuring a wider, rounded bow that accommodates multiple connections and allows for some angular loading.

Key Features:

• Wide, rounded bow shape
• Accommodates multiple connections
• Allows some side loading
• Most versatile shackle type
• Available in screw pin, bolt, or safety pin
• Various sizes and load ratings
• Ideal for general-purpose rigging

Common Applications:

• Marine rigging connections
• Anchor rode attachments
• Sling and chain connections
• Multi-point rigging
• General-purpose connections

D Shackles (Chain Shackles)

Narrower than bow shackles with a D-shaped profile, providing higher strength for in-line loading but less versatile for multiple connections.

Key Features:

• D-shaped profile
• Narrower than bow shackles
• Higher strength for in-line loads
• Less suitable for side loading
• Ideal for single-point connections
• Stronger than equivalent bow shackle

Common Applications:

• Chain connections
• In-line rigging
• Lifting applications
• Towing connections
• High-load applications

Twist Shackles

Feature a swivel design that allows rotation, preventing line twisting and allowing natural load alignment.

Key Features:

• Swivel design allows rotation
• Prevents line twisting
• Allows natural load alignment
• Good for applications with rotation
• Higher cost than standard shackles

Snap Shackles

Quick-release shackles with a spring-loaded pin for fast attachment and detachment, common in sailing applications.

Key Features:

• Spring-loaded quick-release pin
• Fast attachment and detachment
• One-handed operation
• Popular in sailing applications
• Various sizes and styles
• Fixed or swivel eye options

Pin Configurations

• Screw Pin: Threaded pin screws into body, easy to remove, most common type
• Bolt Type: Pin secured with nut and bolt, more secure than screw pin, harder to lose
• Safety Pin: Pin secured with cotter pin or safety wire, prevents accidental opening
• Captive Pin: Pin remains attached to shackle body, can't be lost

Important: For critical applications and overhead lifting, use bolt-type or safety pin shackles to prevent accidental pin removal.

Material Options

• Stainless Steel (316): Best corrosion resistance for saltwater marine applications
• Stainless Steel (304): Good corrosion resistance for freshwater and general use
• Galvanized Steel: Economical with good corrosion protection for general use
• Alloy Steel: High strength for lifting and heavy-duty applications
• Carbon Steel: Basic option for dry, indoor applications

Load Ratings & Standards

• Working Load Limit (WLL): Maximum safe working load for the shackle
• Breaking Strength: Load at which shackle will fail (typically 5-6x WLL)
• Safety Factor: Ratio of breaking strength to working load limit
• Proof Load: Test load applied during manufacturing (typically 2x WLL)

Critical: Never exceed the Working Load Limit. The safety factor accounts for dynamic loads, wear, and other factors. Breaking strength is NOT a working load.

Applicable Standards

• ASME B30.26: Rigging hardware standards
• Federal Specification RR-C-271: Chain and fittings specifications
• ISO Standards: International shackle standards
• Manufacturer Specifications: Always follow manufacturer guidelines

Key Considerations

• Type: Bow for versatility, D for in-line strength, snap for quick release
• Load Rating: WLL must exceed maximum expected loads with safety margin
• Pin Type: Screw pin for convenience, bolt/safety for critical applications
• Material: 316 stainless for saltwater, galvanized for general use
• Size: Pin diameter must fit attachment points
• Application: Marine, lifting, rigging, or general purpose
• Environment: Corrosive environments require stainless steel
• Certifications: Ensure shackle meets applicable standards

Safety Guidelines

• Proper Loading: Load shackles along the pin axis, avoid side loading
• Pin Security: Ensure pin is fully tightened and secured
• Working Load Limits: Never exceed rated WLL
• Inspect Before Use: Check for cracks, deformation, or wear
• Correct Size: Use appropriately sized shackle for the application
• Avoid Shock Loading: Apply loads gradually
• Pin Orientation: Orient pin so it can't unscrew under load
• Regular Inspection: Check for wear, corrosion, and proper function

Critical Safety Warnings

• Never Overload: Exceeding WLL can cause catastrophic failure
• Side Loading: Side loading dramatically reduces shackle strength
• Pin Must Be Secure: Loose pins can fall out, causing load drop
• No Modifications: Never modify, weld, or alter shackles
• Proper Pin Type: Use bolt or safety pin for overhead lifting
• Inspect Regularly: Worn or damaged shackles can fail suddenly

Inspection Guidelines

• Visual Inspection: Check for cracks, deformation, or damage
• Pin Condition: Inspect pin for wear, bending, or thread damage
• Body Integrity: Check bow/body for cracks or deformation
• Corrosion: Look for rust, pitting, or corrosion
• Wear Patterns: Check pin holes for elongation or wear
• Thread Condition: Ensure threads are not damaged or stripped
• Load Markings: Verify WLL markings are legible

Retirement Criteria - Retire Shackle If:

• Cracks visible in body or pin
• Deformation, bending, or twisting present
• Pin holes are elongated more than 10%
• Excessive corrosion or pitting
• Pin threads are damaged or stripped
• Shackle has been shock loaded or overloaded
• WLL markings are illegible
• Any doubt exists about shackle integrity

Care & Maintenance

• Freshwater Rinse: Rinse with freshwater after saltwater exposure
• Lubrication: Apply light lubricant to pin threads
• Storage: Store in cool, dry location
• Corrosion Prevention: Keep clean and dry when not in use
• Proper Use: Use only for intended purposes within rated capacities
• Documentation: Maintain inspection records for professional use

What's the difference between bow and D shackles?

Bow shackles have a wider, rounded bow that accommodates multiple connections and allows some side loading, making them more versatile. D shackles are narrower with a D-shape, providing higher strength for in-line loading but less suitable for multiple connections or side loads. Bow shackles are better for general use; D shackles are stronger for single-point, in-line applications.

When should I use a bolt-type shackle instead of screw pin?

Use bolt-type shackles for overhead lifting, permanent installations, or any critical application where the pin must not accidentally unscrew. The nut and bolt are more secure than a screw pin and won't vibrate loose. Screw pin shackles are fine for general use where frequent removal is needed and the pin orientation prevents unscrewing.

Can I use galvanized shackles in saltwater?

Galvanized shackles will corrode faster in saltwater than stainless steel. For occasional saltwater use, galvanized is acceptable with proper maintenance (freshwater rinsing, inspection). For regular saltwater exposure or permanent marine installations, use 316 stainless steel shackles for maximum corrosion resistance and longevity.

How do I know what size shackle I need?

Shackle size is based on pin diameter and working load limit. The WLL must exceed your maximum expected loads with adequate safety factor (typically 3:1 to 5:1). The pin must fit through your attachment points (chain links, sling eyes, etc.). When in doubt, size up - a larger shackle provides more capacity and is safer than an undersized one.

Why is my shackle pin unscrewing?

Screw pins can unscrew due to vibration or rotation under load. Orient the pin so the load tends to tighten it rather than loosen it. For applications with vibration or rotation, use a bolt-type shackle or secure the screw pin with safety wire or a cotter pin. Never rely on a screw pin alone for critical overhead lifting.

Professional Shackles from US Rigging

US Rigging is a manufacturer and master distributor of climbing ropes, fall protection equipment, and industrial rigging equipment located in Santa Ana, California. With over 40 years of experience, we offer professional-grade shackles in various types, sizes, and materials, engineered for strength, durability, and dependable performance in demanding applications.

Our shackle collection includes bow shackles, D shackles, twist shackles, and snap shackles in stainless steel, galvanized steel, and alloy steel construction with screw pin, bolt-type, and safety pin options. Whether you need corrosion-resistant stainless steel shackles for marine rigging, heavy-duty alloy shackles for overhead lifting, or general-purpose galvanized shackles for rigging operations, we have the quality hardware meeting industry standards for reliable connections.

Browse our shackle selection and contact our knowledgeable team for expert guidance. Trust US Rigging for professional-grade shackles and marine hardware you can depend on.