Series 30 Orbit Double Block
Mouse Over to Zoom
Click to Enlarge

RONSTANSeries 30 Orbit Double Block


In stock online.
Model # 10468593 | Mfg # RF35202UPC # 9316800404971
Series 30 Orbit Double Block


4.0 Stars


Series 30 Orbit Double Block

Name Value
Becket No Becket
Diameter 5/16 Inch or 8 mm
Direction Any
Integral Cleat No Integral Cleat
Mount Type Side Shackle
Ratchet Non Ratcheting
Safe Working Load 992 Pounds
Sheave Diameter 1 3/16 Inches or 30 mm
Type Double
Weight 1.7 Ounces

Product Overview

Lightweight and strong blocks for modern rigging systems.

Ronstan’s goal for the Orbit Blocks™ was to produce a block with the highest strength to weight ratio—and they nailed it. Through extensive computer modeling unnecessary metal components were replaced by engineered light-weight composites without compromising strength. The unique glass fiber reinforced nylon cheeks and head design can be secured using the supplied loop or converted to a soft attachment using a Dyneema® link to further reduce weight. The hollow bearing at the center of single sheave serves as a becket to further reduce weight while adding versatility.

Performance was not lost with the weight savings. In fact the Orbit Blocks™ have the highest working loads in their class and feature an improved two-stage bearing system that efficiently handles static and dynamic forces throughout the load range. High compression grade acetal orbital ball bearings migrate to the loaded area of the sheave to handle light to moderate loads; larger loads are shouldered by the full-contact PTFE impregnated nylon bearing with carbon fiber reinforcement. Conventional and high-tech lines run smoothly over the UV resistant acetal sheave

Sailors can have the best of both worlds with Ronstan Orbit Blocks™. These lightweight and compact bocks are smooth, efficient even under larger loads and are an ideal solution for modern control line systems on dinghies up to larger yachts.

The 30mm double block is a true work horse. Thinner cheeks between the sheaves reduces weight while separating lines. Ideal for 2:1 jib sheet systems, boom vangs, backstays, halyard tuning systems and more.

Key Features

  • Excellent strength to weight ratio
  • Improved two-stage bearing system for efficiency for static and dynamic loads
    • Acetal ball bearings migrate to load areas of the sheave for light to moderate loads
    • PTFE impregnated nylon bearing with carbon fiber reinforcement supports higher static loads
  • Hollow bearing at center of sheave serves as a becket to reduce weight and offer additional versatility
  • UV resistant Aceal high compression sheave that is compatible with conventional doublebraid and high-tech 12 stand lines
  • Can be converted to soft attachment using Dyneema link (Ronstan Part no. RF9003-70)
  • Ideal for
    • 2:1 jib sheet systems
    • Backstay systems
    • Boom vangs
    • Halyard tuning systems
    • Mainsheets
    • General dinghy control lines that use both wire and rope

Orbit Blocks™ User Instructions

Ronstan Orbit Blocks™ Selection Guide

Sheave DiameterLine CompatibilityShackle Pin Diameter (if applicable)
20mm1/4" (6mm)1/8"
30mm5/16" (8mm)5/32"
40mm5/16" (9mm)5/32"
50mm3/8" (10mm)3/16"
55mm3/8" (10mm)3/16"
70mm1/2" (12mm)Only available with Dyneema® link


The West Advisor articles have answered boaters' questions and provided solutions to boating problems for more than 20 years. West Marine has compiled one of the Web's most comprehensive collections of technical boating information articles.

Related West Advisor Articles


Product Q & A