Ropes Are Strong, But This Heavy-Duty Pulley Block Hangs With the Best

There’s a problem in rigging equipment: modern synthetic fiber ropes are almost unbelievably strong. Advanced high-modulus polyethylene (HMPE) fiber ropes like Dyneema® have 15 times the breaking strength of steel (pound-for-pound) at only 15% of a steel cable’s weight (at the same diameter). 

“But...isn’t that good news?” you might ask. Well, yes. Unless you’re basing the maximum load tolerance of a block and tackle system on the rope. 

The issue is the growing disparity between ropes and hardware.  Pulleys tend to have a much lower breaking strength than today’s high-performance synthetic polymer ropes.  In other words, if you get too excited about the strength of your rope, you’re likely to end up with a failure in the pulley system hardware.

Pulley manufacturers continue to make advancements in the tenacity of heavy-duty pulley blocks in an effort to close that gap.  Ronstan is leading the pack. We’re proud to present the latest entry into our line of high-load pulleys.

Why Marine Grade Equipment is Ideal for Industrial Application

A True Heavy-Duty Pulley Block: 

The Ronstan Series 30 High Load Lashing Block

No lashing block in its class is better suited to pair with today’s high-strength fiber ropes.  This new Core Block® from Ronstan handles ropes up to 5/16” and has a breaking load of 3,630 lbs. That’s simply unheard of in a block of this size (it weighs only 1.5 oz).

To achieve this impressive strength-to-weight ratio, the Series 30 High Load Lashing Block was built with an ideal combination of high-strength materials:

  • Toughened, glass-fiber-reinforced nylon frame and cheeks
  • High-grade stainless steel sheave, ball bearings, and hub
  • Uses a Dyneema® soft attachment shackle

Each of these components has been perfectly matched to use with load lines, lashings, and beckets that boast ultra-high load ratings. But even with its class-leading performance, the Series 30 High Load Core Blocks are much more than just heavy-duty pulley blocks. They also feature:

  • Friction-optimized ball bearing and ball race systems
  • Consistent low-friction performance across the full working load range
  • A narrow profile and compact design
  • Sleek, contemporary styling
  • Perforations in the head for whipping twine (to secure the lashing line)
  • Built-in becket take-off or tie-up through the hole in the central hub
  • The option to shackle-mount with a soft link

Ultra-High Loads? No Problem for This Lashing Block.

The range of applications for Dyneema® soft attachments, beckets, and load lines is naturally vast.  But can the pulley system hardware keep up? The Ronstan Series 30 High Load Lashing Block is the perfect solution for applications all the way from commercial entertainment venues to home projects. Use this heavy-duty pulley block for:

  • Large static loads (non-moving and holding)
  • Large dynamic loads (moving and variable)
  • Industrial block and tackle systems
  • Lifting, hoisting and holding items aloft

With such an enormous load rating for such a small pulley, the limits are more likely to be dictated by your choice in soft attachments and joining methods.  Knots, splices, and stitching will reduce the total breaking load of the rope—but it won’t affect this lashing block while properly rigged.

For optimal results, ensure that the soft attachments for your lashing block are mounted to a surface with a smooth, well-rounded profile.  This minimizes chafing and abrasions, preserving the strength and longevity of the rope.    

We also recommend using a line with a smaller diameter and multiple passes through the hub, rather than the full 8mm size the block can handle.  Thinner lash lines wrapped a few times create more secure knots and a neater end result. And don’t forget to stabilize the rig with whipping twine, so there’s no twisting in the system.  

Now you’re ready!  High static load? No problem.  Variable, dynamic, or axial loads? Our lashing block can take it. With this heavy-duty pulley block, you’re prepared for anything.

Why Marine Grade Equipment is Ideal for Industrial Application

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Ronstan’s end-to-end design, manufacture and distribution operation delivers high specification products for all serious hardware applications.

Our state-of-the-art design facilities and manufacturing plant handles more than 4.9 million units each year.

As one of the top three sailboat hardware brands globally we know what it is like to deliver great equipment that can handle challenging conditions.