Who’s it for? A myriad uses on all boat types, these are light and inexpensive enough to buy in bulk and keep as spares. Contact: www.sailtek.org.uk

Product Overview

Overall rating:

Ronstan Shock Block


  • • neat and compact
  • • lightweight
  • • largest has a 1,000kg breaking load


Ronstan Shock Sheaveless Block


Price as reviewed:


These neat and compact aluminium, low-friction, sheaveless blocks have a multitude of uses. The smallest, weighing just 2g, will take lines of up to 5mm and has a breaking load of 350kg, making it ideal for applications such as lazyjacks or simple lashings on many yachts.

The XL size block will take lines of up to 10mm, weighs 12g and has a 1,000kg breaking load, opening up a much wider variety of applications, including purchase systems or hoists for outboards and passerelles. Alternatively, in the dinghy and keelboat world, they can be used with tweakers, vang systems and barber haulers.

We used the smaller Shock Blocks in the vang system of a one-design keelboat.

ronstan shock block

Ronstan Shock Block

Price: £30 for two / $15.59 for one

Buy Ronstan Shock Block from Amazon.co.uk
Buy Ronstan Shock Block from Westmarine

Rupert Holmes Brown 2

Tested by Rupert Holmes


This proved to be a neat, streamlined and lightweight alternative to a traditional block, and there was no discernible increase in friction.