Ball Bearing


Series 40 Ball Bearing Orbit Block™, Auto Ratchet

Single ratchet block with fully Automatic load sensing ratchet engagement and swivel shackle head


Up to 14:1 holding power - highest available.

Smooth easing of sheets.

Fully Automatic load sensing ratchet engagement.

Swivel shackle head for unlimited block rotation.

Stainless steel shackle head and compatibility with sharp fixing points.


Product Specifications
Pin Ø (in)5/32
Max. Rope diameter (in)516
M.W.L. (lb)385
Sheave diameter (in)1 9/16
B.L. (lb)1100
Weight (oz)1.3

Product Information

Automatic ratchet option

With automatic models, 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. The Series 40 delivers up to 14:1 holding power, almost double that of our nearest competititor.

The unique sheave design has 8 gripping faces which directly resist loaded line movement. Traditional designs have 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.

Smooth easing of sheets

With auto models the sheet runs out smoothly and freely as soon as the ratchet mechanism disengages. When engaged, and with manual models, the sheave cross - hole geometry eliminates the 'shuddering' ease-out that you can expect from traditional v-groove ratchet blocks.

Low profile stand-up kit allows  0° or 90° alignment

Stand-up kits feature a clatter-free rubber boot.  It's a neat low-profile solution which allows full articulation.

Technical Information


  • Dinghy mainsheet systems
  • Mainsheet fine tune systems on sportsboats & small keel boats
  • Mainsheet systems on sportsboats using RF7 mainsheet swivel cleat unit
  • Spinnaker and job sheets on dinghies - especially modern asymmetric classes
  • Control line applications on larger yachts



  • Sheave: Anodised Aluminium
  • Ball Bearings: High compression strength carbon black Acetal
  • Frame/Cheeks: Toughened, glass fibre reinforced Nylon
  • Shackle and Head fitting: Grade 316 stainless steel


Resource Files


Need some advice?

Send us a

Find a