Ronstan 40mm Soft Attachment Block, Single

Soft Attachment Block

Designed from the outset to deliver outstanding performance, these blocks achieve the highest ratings for dynamic load vs sheave diameter in our keelboat block range. They are built to perform and built to last. Every SA Block features fully machined, anodised aluminium cheek plates. Sheaves run on duplex stainless steel hubs and incorporate precision composite journal bearings and thrust washers. The soft attachment is a purpose designed Dyneema® SK99 cord shackle with titanium dog bone.

RF47109
S40 Soft Attachment Block

Sheave diameter: 42mm
Max rope diameter: 12mm
M.W.L: 2000kg
B.L: 4000kg
Weight: 165g

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.

Attach, detach and open

The soft shackle provides a simple means of attachment, secured with the titanium 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.

Soft shackle with titanium dog bone

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

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.

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

Features:

• Soft shackle retained by elastomer guides
• Titanium dog bone allows for easy attachment and removal of the block
• Cheek plates twist to open the block and close with spring loaded ball lock securing in place
• Primary bearing and thrust washers for optimum dynamic and static performance.

Materials:

• Cheek plates and sheaves: Aluminium alloy, anodised
• Bearings and thrust washers: Propertary self-lubricating composite
• Hubs: Grade 2205 stainless steel
• Soft shackle: Dyneema® SK99 cord with proprietary coating, titanium dog bone, TPV collar
• Dyneema® is a registered trademark of DSM IP Assets B.V.

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