BLOCKS SELECTION ADVICE

1.

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.

2.

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 salt 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.

3.

ALUMINIUM SHEAVE OPTIONS
Selected models are available with an aluminium sheave which has a deep groove profile specifically made for use with wire.

4.

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.

5.

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.

6.

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.

1.

LIGHTWEIGHT
Kilogram for kilogram of working load, 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. 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.

2.

SIMPLE AND SECURE ATTACHMENT
Block cheeks are manufactured from glass filled nylon for maximum strength. Material optimisation and the cut-away design minimises weight and allows easy fresh water rinsing of salt 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.

3.

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 modelled to be stress optimised. The Dyneema® Link is produced from Robline SK78 fibre, which is 10 times higher and lighter than steel, and provides the final connection from the block to the load point.

4.

LOW PROFILE AND COMPACT
The flexible Dyneema® Link provides controlled rotation and 0° or 90° orientation. It connects directly to the head of the block rather than to an intermediate head post. This reduces weight and gives the lowest possible profile while allowing full articulation. Beckets have been carefully designed to minimise height.

1.

MANUAL, AUTO AND AUTO+MANUAL BLOCKS

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.

2.

SIMPLE AND SECURE ATTACHMENT

The Dyneema® Link is easily fitted and is retained securely by a moulded retainer clip. The flexible link can be left with one end attached to the block when fitting - no more lost shackle pins.

The system is compatible with Dyneema®/Spectra® strops, webbing and carbon connection points - much more so than steel loop tops or shackles.

1.

ULTIMATE DYNAMIC AND STATIC LOAD PERFORMANCE

SA Blocks incorporate a full contact, selflubricating composite journal bearing running on a polished duplex stainless steel hub, to maintain low friction performance under heavy dynamic and static loads. Thrust washers in the same composite material are positioned between the sheave and the cheek plates to handle the high side loads that can be generated when line entry and exit alignment is not ideal. Testing has shown reduced friction and greater durability than ball bearings in this application.

2.

ATTACH, DETACH AND OPEN

The soft shackle provides a simple means of attachment, secured with the aluminium dog bone but easily opened when necessary to detach the block. With the shackle open a gentle rotation of the cheek plates opens the head of the block so it can be fitted to a standing line. To close the block, rotate the cheeks back to the closed position until the spring loaded ball lock secures them in place. No additional external straps or bands required.

3.

SOFT SHACKLE WITH ALUMINIUM DOG BONE

Drawing on the expertise of Nodus Factory, many design iterations were tested before finalising specifications of the Dyneema® SK99 cord shackle and aluminium dog bone. Proprietary Nodus Factory splicing techniques and fibre surface coating ensure secure load transfer from the block and maximum durability.

4.

ALUMINIUM ALLOY CHEEK PLATES & SHEAVES

Block cheeks and sheaves are precision machined from high strength aluminium alloy, then anodised for durability and corrosion resistance. The soft attachment through the hub provides a protective buffer between the block and boat surfaces. Retaining guides in soft elastomer ensure that the block remains aligned within the soft shackle.

5.

A MULTITUDE OF APPLICATIONS

Suited to temporary or permanent line deflection, load carrying and snatch block applications including:

• 2:1 Main halyards
• Headsail and spinnaker sheets
• Mast base halyard deflection
• Running backstays

1.

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.

2.

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. The Orbit sheave has captive acetal or Torlon® ball bearings for side thrust loads, maximising the available bearing surface for its Torlon® needle rollers to achieve a high strength-to-weight ratio.

3.

UNIVERSAL HEAD

Head posts of swivel blocks can be locked at 0° or 90°. The high resistance shackles are forged in grade 17-4PH stainless steel.

4. 

HALYARD BLOCKS

These blocks have been designed primarily for attachment around the mast collar to lead halyards aft from the mast base to winches. The head of the block has a removable pin which enables easy attachment to the deck padeye or mast collar. This method of attachment provides a low lead aft to organisers or winches.

5.

STROP & LASHING BLOCKS

These lightweight alternatives to traditional blocks are used where a rope lashing attachment is passed through the hub of the sheave to provide a failsafe feature. Lashing blocks have incredibly high breaking loads – up to 40,000kg. Their versatility makes them suitable for many applications, with four lashing guide holes to allow for multiple attachment options including single, parallel and split lashings. The central hole can also be used for a becket in 3:1 purchase systems. Every detail has been carefully executed to achieve the best optimisation of performance, size, weight and ultimate strength available today.

6.

FOOT BLOCKS

The bottom plate incorporating the hub section is machined from solid alloy for maximum integrity of the load bearing structure. The top cover plate protects the sheave against impact, prevents dirt and grit from entering the hub area, and can be removed for service without removing the mounting bolts that secure the block through the base plate to the deck.

7.

STAND-UP BLOCKS

A number of stand-up solutions are available for Orbit Blocks™. These include assemblies incorporating padeye and rubber boot, stand-up spring kits and blocks with special swivel-eye to suit non-tumble padeyes.

1.

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.

1.

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.

1.

THE IDEAL BLOCK FOR HIGH LOAD APPLICATIONS

Wear resistant sheave materials, either in lightweight, self lubricating polymer or in alloy with special purpose bushes, are suitable for use with rope or wire. High Load blocks provide outstanding static load performance and are typically used for halyards, backstays, etc.

1.

HOLDING POWER

Quietly boasting an increased 20:1 holding power, the Ultimate Ratchet Block™ has a strong dinghy pedigree and has been at the top of the Olympic and World Championship podium, whilst also providing a touch of finesse to main and spinnaker sheet systems aboard sportsboats and small keelboats.

1. 

LOW WEIGHT

The Ultimate range features a patented extruded-hole ratchet sheave, hard anodised cheek plates and a low friction carbon black Acetal ball bearing system that also provides a premium control line solution for larger yachts.