Block triple Ratchet Orbit underhung becket, adjustable cleat and swivel (only auto) 55mm

Up to 20:1 holding power
Smooth easing of sheets
High performance cleating
Swivel shackle head for unlimited block rotation.
Stainless steel shackle head for ultimate durability and compatibility with harsh fixing points.
Ultra low profile integrated beckets.

Sheave Ø 55 mm
Max. Rope Ø 10 mm
Max. Cable Ø mm
Pin Ø mm
M.W.L. 750* kg
B. L. 1500 kg
Weight 392 g

Product Information
Automatic ratchet block
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 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. 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.
* Selected Series 55 models.

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.
Click to view full Practical Sailor's Ratchet Click-off article



Applications
Mainsheet systems and spinnaker sheets on dinghies, catamarans, sportsboats and small keel boats to 9m (30ft)
RF55410 when paired with a RF56330B and a RF35101 lashed to the becket produces a powerful 8:1 mainsheet system for use on catamarans to 5.5m (18ft). This can be increased to 9:1 by replacing the RF35101 with a RF35202
Halyard, vang and backstay applications on boats to 8m (26ft)
Control line applications on larger yachts.

Materials
Sheave: Anodised Aluminium
Ball Bearings: High compression strength carbon black Aceetal
Frame/Cheeks: Toughened, glass fibre reinforced Nylon
Rope Link: UV stabilised, multi-strand impregnated SK75 Dyneema®