Block and Pulley Selection Advice

All Purpose Utility Pulley BlockUtility Blocks – All Purpose

Use them Anywhere

All Purpose utility blocks are a great choice for durability and a long service life. They feature self-lubricating acetal polymer sheaves running on polished stainless steel races and perform equally well with dynamic loads and static loads.

  • Available in 40 and 50mm (1 9/16″ and 2″) sheave diameters to suit a range of rope diameters and load requirements
  • Features like adjustable cleat arms and Captive Lock universal heads offer the same versatility usually found only in Ball Bearing blocks
  • The comprehensive range of sizes and configurations offers solutions for every application

Available in sheave sizes 16mm (5/8″) to 50mm (2″).


  • Dynamic and High Static Load Performance.
    UV stabilised Acetal sheaves provide bearing performance on a polished stainless steel race that performs equally well with dynamic and static loads. Sheave design features side ribs to minimise weight and enhance strength. Self-lubricating Acetal polymer minimises friction and ensures dependable load bearing reliability.
  • Stainless Steel Cheek Plates and Straps.
    For ultimate strength and durability Series 60 and 75 AP blocks have grade 316 stainless steel cheek plates and load straps. Cheek plates have a black chrome finish and are flared at the rope entry and exit points to minimise rope chafe.
See the All Purpose Utility Block Range



Ball Bearing Utility BlocksUtility Blocks – Ball Bearing

Ronstan’s Ball Bearing utility blocks, conceived and engineered for low friction performance, have rapidly become the international choice for high performance hardware.

  • Highly efficient, low friction bearing systems for optimum sheeting and trimming performance
  • Comprehensive range of sizes and configurations offers solutions for powerful multiple purchase and cascade systems
  • Fiddle block flexibility
  • High performance cleating
  • Practical features designed into the blocks provide extra versatility

Available in sheave sizes: 15mm (5/8″), 20mm (3/4″), 30mm (1 3/16″), 40mm (1 9/16″), and 50mm (2″).


  • Ball Bearing Blocks
    Meet the high performance demands of running sheet applications with a unique two-stage bearing system. Stage 1 – Under moderate loads, Acetal ball bearings ensure minimum friction. Stage 2 – Under heavy loads, where deformation of ball bearings alone would result in increased friction, a sliding Acetal bearing on a polished stainless steel race takes over, maintaining low friction performance. Regular flushing with fresh water to remove salt and sand will maintain optimum performance over a long service life. These blocks are an excellent choice for main and jib sheets, spinnaker sheets and control lines.
  • Aluminium Cheek Plates
    For extra performance Series 60 and 75 BB blocks have alloy cheek plates and a screw-together construction for ease of servicing.


See the Ball Bearing Utility Block Range



Ball Bearing Orbit BlockOrbit Blocks™ – Ball Bearing

Less Friction, Ultimate Performance

Ball Bearing Orbit Blocks™ have been engineered to achieve the highest possible strength-to-weight ratio, using composite reinforced polymer materials.

The unique orbital version of our 2-stage ball bearing system maximises the available bearing surface and positions recirculating ball bearings exclusively within the loaded area of the sheave. A secondary full-contact bearing maintains low friction across the full working load range.

Swivel head models with stainless steel shackles provide full rotation and ultimate durability.

Orbit Blocks™ are fitted with our carbon-fibre reinforced C-Cleat™ for secure rope holding with low entry and exit efforts, and fairleads for fast action from any angle. Cleat arms have a wide range of adjustment and calibration marks for setting your preferred cleating angle.

Available in sheave sizes: 20mm (3/4″), 30mm (1 3/16″), 40mm (1 9/16″), and 55mm (2 (5/32″)

  • Lightweight
    BB and RT Orbit Blocks are the world’s lightest. To gain peak performance, we engineered out the heavy steel load straps, head post, shackle, full-length fasteners, and cleating accessories. Through extensive research and development, we replaced virtually all metal components with high-tech polymers and fibre equivalents. The unique orbital design allows the bearing to only be in the active areas of the floating sheave. This minimises the mass of the inactive return race and hub. Weight and bulk are further reduced in the different block configurations. The ball bearing single and becket block has a through-sheave becket arrangement. The result? The lowest weight possible without sacrificing performance. Multi-sheave blocks have only single intermediate cheeks and an ultra-light and efficient head arrangement. This gives a 30% weight saving advantage over the nearest competitor. Other brands just link together their single blocks. This results in unnecessary double cheeks between each sheave, held together by a heavy steel channel across the top of the block.
  • Highest working load in its class
    The orbital ball-bearing arrangement gives the largest possible bearing race diameter. This maximises load performance. The proven Ronstan 2-stage bearing system features high compression grade acetal ball bearings and a secondary full-contact bearing. This gives minimum friction across the full working load range. The floating sheave and bearing system is supported by a fibre-reinforced load frame. The design was computer modeled to be stress optimized.


See the Ball Bearing Orbit Block Range



Orbit Blocks™ – Ratchet

Holding Power

Multiple gripping faces machined into our ratchet block sheaves work in conjunction with our unique cross-hole geometry, delivering up to 20:1 holding power to resist slipping of the loaded line while minimising rope wear. Ball bearings ensure minimum friction under load and a free running sheave when the ratchet is disengaged.

Control switches are located on both sides of the block to remain accessible wherever the block is fitted. In auto mode, the ratchet mechanism engages when load is applied but disengages when released to let the sheet run out freely. In manual mode, the switch is used to set up the block with ratchet either on or off as required.

  • Manual, Auto and Auto + Manual blocks
  • Ratchet block holding power
  • Simple and secure attachment
  • Smooth easing of ropes
  • High performance cleating

Available in sheave sizes: 40mm (1 9/16″) and 55mm (2 5/32″)

  • Ratchet block holding power
    Quite simply, Ronstan Ratchet Orbit Blocks™ have the highest holding power available. The sophisticated NC-machined sheave features Generation 2 of our patented sheave cross-hole geometry. Its holding power is up to 25:1, almost double that of our nearest competitor.
  • The unique sheave design has 12 gripping faces which directly resist loaded line movement. Traditional designs have only 8 faces with an angled resistance to line movement. Our Generation 2 design has straight resistance faces which both distribute the load and minimise rope wear. These faces are offset from the radial line, to draw the rope down into the gripping area when under load.


See the Ratchet Orbit Block Range



Core Blocks - use them anywhereCore Blocks™ – Ball Bearing

Use Them Anywhere

A balanced design approach incorporating functionality, performance and style makes our Core Blocks™ the right choice for a variety of applications. A tuned 2-stage bearing system provides excellent performance across the full working load range with an integrated thrust bearing feature and the resilience to handle high dynamic or static loads. Acetal & aluminium sheave options, alloy cheeks and stainless fixings complete the durable package.

  • Dynamic and high static load performance
  • Aluminium sheave options
  • Aluminium alloy cheek plates
  • Universal head
  • Suits pre-spliced lines
  • Fully articulated stand-up

Available in sheave sizes: 45mm (1 3/4″), 60mm (2 3/8″), 75mm (3″), and 100mm (4″)

  • Dynamic and high static load performance
    The Ronstan Universal Bearing incorporates our proven 2-stage bearing system.
    Stage 1 – Under moderate loads, acetal ball bearings ensure minimum friction.
    Stage 2 – Under heavy loads, where deformation of ball bearings alone would result in increased friction, a sliding acetal bearing on a polished stainless steel race takes over, maintaining low friction performance.
    Additionally the ball bearings are configured to act as a thrust bearing between the sheave and cheeks, preventing the sheave from rubbing on the cheeks and causing friction when the line lead in and out of the block isn’t perfect. Particularly important for foot blocks.
  • Aluminium alloy cheek plates
    Block cheeks are manufactured from the highest quality aluminium alloy for maximum strength. Material optimisation and the cut-away design minimises weight and allows easy fresh water rinsing of dust and debris from the bearings.
    Cheek design has been further styled with flaring at the block throat and reduced gap between the cheek and sheave, minimising rope wear, and the hollow hub can be used as a becket take-off or tie-up point.
  • Aluminium sheave options
    Selected models are available with an aluminium sheave which has a deep groove profile specifically made for use with wire.
  • Universal head
    The head assembly incorporates a brass bearing washer to provide smooth 360° rotation of the post and shackle. A set screw arrangement allows the head to be locked at 0° or 90°. Shackles are high quality forged grade 316 stainless steel.
  • Suits pre-spliced lines
    Removable becket pins allow fitting of pre-spliced lines. The flush fit becket pin head is kind on deck surfaces and won’t snag lines.
  • Fully articulated stand-up
    Stand-up models have a low profile linkage that provides full rotation and articulation. A high strength precision cast padeye minimises the footprint and a dedicated rubber boot ensures the block is held upright when not loaded.


See the Core Block Range



Roller Ball Orbit BlocksOrbit Blocks™ – Roller Ball

Specify the Best

Roller Ball Orbit Blocks are a no-compromise product range developed to meet load and performance demands with characteristics including:

  • The highest strength-to-weight ratio
  • Minimal friction loss, especially when working at high loads
  • Totally reliable and trouble free performance
  • Simplicity of design and construction to facilitate maintenance and servicing
  • Elegant, functional styling and finish.

Available in sheave sizes: 60mm (2 3/8″), 75mm (3″), 100mm (4″), and 125mm (5″).

  • Bearing System
    The Orbit sheave has captive Acetal or Torlon® ball bearings for side thrust loads, eliminating the need for side retainer plates. This reduces weight and allows for a wider bearing surface that can accommodate longer Torlon® needles – achieving a substantially higher strength-to-weight ratio.
  • Design Simplicity
    There are only 3 primary components to the block: the twin side pieces, sculptured from solid high grade alloy, and the one-piece sheave with its captive ball bearings. Bearings are easily rinsed clear of salt and debris.
See the Roller Ball Orbit Block Range



Lashing Orbit BlocksOrbit Blocks™ – Lashing

No Compromise

Lashing Orbit Blocks™ are a no-compromise product range with incredibly high breaking loads – up to 19,200kg (42,990lb) – developed to meet extreme load and performance demands. They are lightweight with a high strength-to-weight ratio, allowing for compact systems and significant weight savings. Versatile in many applications, the four lashing guide holes allowing for multiple attachment options including single, parallel and split lashings, and the central hole can be used for a becket in purchase systems.

The two screw-together side cheeks incorporating the bearing hub are precision machined from solid alloy, leaving material only where it contributes to the load carrying capacity of the block. The only fasteners used are for the guide rollers near the head. The Orbit sheave runs on extended length Torlon® rollers with captive ball bearings for side thrust loads, and is easily accessible for routine servicing. Every detail has been carefully executed to achieve the best optimisation of performance, size, weight and ultimate strength available today.

  • Extremely high breaking loads for size and weight
  • Minimal friction loss across the working load range
  • Reliable, proven performance
  • Simplicity of design and construction to facilitate maintenance and servicing
  • Elegant, functional styling and finish
  • Central hole can be used as a becket take-off/dead end in a 3:1 purchase system.

Available in sheave sizes: 60mm (2 3/8″), 80mm (3 1/8″), 100mm (4″), and 125mm (5″).


See the Lashing Orbit Block Range


About Us

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.

Want to learn more about our products?

Ronstan International Inc
45 High Point Avenue, #2 Portsmouth
Portsmouth Rhode Island 02871
+1 (401) 293 0539 $$$
Ronstan International Inc
45 High Point Avenue, #2 Portsmouth
Portsmouth Rhode Island 02871
+1 (401) 293 0539