Wooden snatch blocks, also known as wooden shell snatch blocks, are specialized pulleys featuring a side-opening plate that allows a rope or cable to be inserted without threading it through the entire block. Primarily used in marine, rigging, and agricultural applications, they are designed to redirect pulling force or increase mechanical advantage for heavy loads.
Key Specifications & Selection
- Safe Working Load (SWL): Capacities vary significantly by size, ranging from approximately 2 tons (3-inch block) to over 3.5 tons (12-inch block).
- Rope Compatibility: Designed for use with manila, hemp, or synthetic ropes. Typical sizes accommodate rope diameters from 12mm to 36mm.
- Number of Sheaves – We carry single to triple and some cases quadruple sheave types for different requirements
- Attachment Types: Available with swivel hooks, shackles, or eyes to provide flexibility in connecting to fixed points or moving loads.
Functional Features for Rigging
- Maintenance-Friendly Design:High-quality blocks, such as those from Tall Ship Blocks, use stainless steel axles secured by a single screw, allowing the block to be easily dismantled for inspection.
- Sheave Materials:While traditional sheaves were wood or brass, modern functional blocks often use white Ertacetal (a high-strength plastic) or Tufnol for low friction and high load-bearing capacity.
- Corrosion Resistance:Marine-grade blocks are often finished with up to 8 coats of marine varnish and utilize galvanized or polished stainless steel internal straps to handle offshore environments.
- Side-Opening Mechanism:Like all snatch blocks, these feature a rotating “cheek” or side plate that allows you to loop a rope into the pulley without needing to thread it from the end.
Specifications by Shell Size
Safe working loads (SWL) for wooden maritime blocks vary by size. Standard ratings include:
- 6-Inch Block:1.0 Ton SWL; suitable for ~18mm to 24mm rope.
- 8-Inch Block:1.2 to 2.1 Ton SWL; suitable for ~28mm rope.
- 10-Inch Block:1.8 to 2.9 Ton SWL; suitable for ~32mm rope.
- 12-Inch Block:3.5 Ton SWL; suitable for ~36mm rope.
