SHOCK - The Sheaveless Block

Ronstan Sheaveless Blocks

From simple off the beach dinghies to massive foiling multihulls, today’s yachts and the systems for rigging and controlling them are more varied than ever.
This diversity creates unique demands on the hardware which are nowhere more apparent than in the category of blocks. Ball and roller bearings can still provide the lowest levels of friction, but in many applications and environments, strength-to-weight ratio, durability and simplicity are the key requirements. These applications have seen the evolution of apparently simple products, whose outward appearance belies the exacting engineering and advances in materials technology that they are based on, and which still deliver excellent free running performance. Custom made low friction rings and solid fairleads have filtered down from Grand Prix racing to the realm of recreational sailor.

See the full SHOCKS range SHOCK or BLOCK - Options for every application


Unlimited uses:

  • Vangs
  • Tweakers
  • In-spar Purchases
  • Outboard Raisers
  • Barberhaulers

  • Sail Cover Zipper Lines
  • Ladder Hoist
  • Lazy Jacks
  • Cunningham
  • Garage Hoists

  • Traveller Controls
  • Kite Bridles
  • Leech Lines
  • Trailer Tie-downs
  • Guy Lines

  • Trapeze Elastics
  • Control Lines
  • 2:1 Halyards
  • Luggage Ties

Shock - Sheaveless Block - Features -
Shock - Sheaveless Block - Features
Shock - Sheaveless Block - Features
Shock - Sheaveless Block - Features
Shock - Sheaveless Block - Features
Shock - Sheaveless Block - Features


  • Performance & Versatility
  • Ultra Lightweight - only 2g!
  • Ultra Compact
  • Durable
  • Colour Coded
  • Impact Resistant
  • Small Line Optimised
  • High Load Capacity - 350kg (770lb) BL
  • Poor Alignment Tolerant
  • Soft Attachment Compatible
  • Versatile
  • Grit and Salt Resistant
Shock - Sheaveless Block - RF8080BLU
Shock - Sheaveless Block - RF8080GRN
Shock - Sheaveless Block - RF8080GRY
Shock - Sheaveless Block - RF8080R

2.5g 22.9mm 14.9mm 8.5mm 1.4mm - 5.0mm 8mm wide/ 
5mm diam.
0.01oz 7/8" 9/16" 5/16" 1/16" - 3/16" 5/16" wide/ 
3/16" diam