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Ronstan "Orbit" Ratchet Cheek Block - 55mm - Counterclockwise Rotation

Ronstan "Orbit" Ratchet Cheek Block - 55mm - Counterclockwise Rotation

SKU: 504630

$77.951 / EA

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Ratchet Orbit Block™ - Series 55 RT

Cheek Block - Auto & Manual

  • Automatic and Manual ratchet in one block
  • Up to 20:1 holding power
  • Smooth easing of sheets
  • High performance cleating

Automatic Ratchet Blocks
Now you can enjoy the flexibility of setting up your ratchet blocks to suit yourself. Ronstan is the only company that offers a ratchet block with both auto and manual engagement modes. In the auto mode, the ratchet mechanism engages when load is applied, but switches off when it's released. This lets the sheet run out smoothly and freely, which is great for rapid easing of the sheet and for gybing asymmetric spinnakers. In manual mode, the ratchet mechanism can be switched on or off as required. This is the preferred mainsheet set-up for may top sailors. Try the block in both modes and see which you prefer - you really can't go wrong.

Awesome Ratchet Block Holding Power
Ronstan Ratchet Orbit Blocks™ have the highest holding power available. The sophisticated NC-machined sheave features Generation 2 of their patented sheave cross-hole geometry. Its holding power is up to 20:1, almost double that of the nearest competitior. 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. Ronstan's Generation 2 design has straight resistance faces, which both distribute the load and minimize rope wear. These faces are offset from the radial line, so as to draw the rope down into the gripping area when under load.


  • Sheave - Hard-anodized aluminium
  • Ball Bearings - High-compression-strength carbon black Acetal
  • Frame/Cheeks - Toughened, glass-fibre-reinforced Nylon

Mfg No. RF56151A

Sheave Diameter 2-5/32" (55mm)

Max Line Diameter 3/8" (10mm)

Max Working Load 550 Lbs (250kg)

Breaking Load 1,540 Lbs (700kg)

Holding Power 20:1

Weight 2.7 oz (76g)

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