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February 15, 2022 2 min read

40mm vs 57mm Laser Main Sheet Block

The Laser has had many different configurations during its life, in recent years alongside the 8 to 1 downhaul system we have also seen more people switching out their 57mm ratchet block for a 40mm ratchet block.

Why is this?

The main reason is the thickness of the main sheet. Most Lasers have had in the past 8mm main sheets. The 8mm rope sat inside the sheave of a 57mm block and gives more friction therefore more grip. But in recent years around the boat park, you may have seen people using 6mm main sheet rope.

6mm lines like Kingfisher Evolution Sheet and Marlow Marstron are lighter and smaller creating less friction through your blocks, making your sailing easier. Therefore having more control over the main sheet in lighter winds and the sheet going out easier and quicker when gybing and starting the downwind leg.

The 57mm block is designed to work with lines up to 10mm and by having a 6mm line running through the block it will work fine but the block is not working at its peak performance.

The 40mm can also take up to 10mm rope but being narrower and shallower the sheave works very effectively with 6mm and 7mm ropes.

Another big advantage to having the 40mm ratchet block is, on a winder day when you have all your control lines pulled hard on and excess rope in the boats cockpit you are less likely to have your controls getting caught and tangled in the larger opening of the 57mm block.

Here are the links to the two blocks for you to compare. Which do you use?

Harken 2608 40mm Ratchet Block With Swivel