2020 Ronstan Sailboat Hardware Catalogue - VIEW CATALOGUE

Orbit Block™

PHOTO CREDIT:© Gordon Upton / guppypix.com

Series 70 Ratchet


  •  Fully automatic, load sensing ratchet engagement
  •  Up to 25:1 holding power
  •  Easily fitted and securely retained Dyneema® Link head

  • Share:
  Product No. Desc. Sheave ØMax. Rope ØMax. Cable ØPin ØM.W.L.B. L.Weight  

These blocks have been specifically designed and optimised for use on racing sailboats and the conditions encountered in this unique application.  They should not be assumed suitable for other non-marine or industrial applications. For further details on associated risks see
Orbit Block Usage and Considerations

Automatic ratchet block

The auto mode of the ratchet mechanism engages when load is applied, but switches off when it's released.  This lets the sheet run out smoothly and freely-great for rapid easing of the sheet and for gybing asymmetric spinnakers.


Awesome 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 21:1, almost double that of our nearest competitior.

The unique sheave design has 12 gripping faces which directly resist loaded line movement.  Traditional designes 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.


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 caron connection points - much more so than steel loop tops or shackles.


Smooth easing of sheets

In auto mode, the sheet runs out smoothly and freely sas soon as the ratchet mechanism disengages.  In manual mode, the sheave cross-hole geomtry eliminates the 'shuddering' run-out that you can expect from traditional v-groove ratchet blocks.


  • Dinghy mainsheet systems - when maximum holding power is required.
  • Mainsheet systems on sportsboats using RF7 mainsheet swivel cleat unit.
  • Control line applications on larger yachts.
  • Spinnaker sheets on sportsboats and small keel boats (lateral lead blocks).
  • Spinnaker sheets on sports boats and small keel boats - especially modern asymmetric classes.
  • Sheave: Hard anodised Aluminium
  • Ball Bearings: High copression strength carbon block Acetal.
  • Frame/Cheeks: Toughened, glass fibre reinforced Nylon.
  • Rope/Link: UV stablised, multi-strand impregnated SK75 Dyneema.