Ronstan Series 55 Orbit Ratchet Block With Swivel Shackle Head

This 55mm Ratchet block from Ronstan can by the flick of a switch be a manual on/off ratchet or an automatic ratchet block. This block has a swivelling shackle head.

- Automatic and Manual ratchet in one block
- Up to 20:1 holding power
- Smooth easing of sheets
- Swivel shackle head for unlimited block rotation.
- Stainless steel shackle head for ultimate durability and compatibility with harsh fixing points.

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 20:1 holding power, almost double that of our nearest competitor.

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.

Simple and secure attachment 
A swivelling shackle is used for attaching the block, which allows for unlimited twists of the block.

Smooth easing of sheets
In automatic 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. With ratchet engaged,the sheave's cross hole geometry eliminates the 'shuddering' ease-out that you can expect from traditional v-groove ratchet blocks.

Applications
Dinghy mainsheet systems
Spinnaker sheets on dinghies
Control line applications on larger yachts 
Popular choice on the Topper, Laser, GP14 and many other boats.

Materials
Sheave: Hard anodised aluminium
Ball Bearings: High compression strength carbon black Acetal
Frame/Cheeks: Toughened, glass fibre reinforced Nylon
Head fitting: Grade 316 stainless steel.