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The mainsheet is a rope controlling the angle of the boom, and thus the mainsail, relative to the boat. This is the main control that affects the amount of wind that is caught by the mainsail.

You use the mainsheet rope, as well as the other sail control ropes, to pull in the sail to catch more wind, let it out to catch less breeze, and to tune the sail so it has the most efficient shape allowing you to move the boat as fast and as controlled as possible. If there is too much wind in the sail, let the mainsheet out.

The main objective of tuning the mainsail with the mainsheet is to keep the Laser flat.

Generally speaking the more wind you can harness in the sail, and the harder you hike, while keeping the boat flat, the faster you will go. So if that means that you’ve eased the sail and it is flapping in a gust, as you are hiking out as far as possible, and you’ve managed to keep the boat flat, then you’ve done well. Of course, the other controls (vang, cunningham, outhaul) also have to be trimmed accordingly, but they are not adjusted nearly as frequently.

You should have the mainsheet in your hand all the time, along with the tiller in the other.

Laser mainsheet attached to boom on deck

Laser mainsheet attached to boom on deck

Laser mainsheet, blocks and cleats in cockpit

Laser mainsheet, block, and cleats in the cockpit

Mainsheet rope specs

This rope is usually ~14m, 46ft in length, and made from 6-8mm, ¼-5/16 inch rope for easy handling.

While out on the water it is advisable to tie a figure 8 knot in both ends of the mainsheet rope. At the boom end, this is so that the mainsheet can be pulled fully on so that it is in the block-to-block position. At the other end so that it doesn’t pull through the mainsheet block in the center of the cockpit.

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  1. Rob Tindall on June 29, 2016 at 9:49 pm

    In above picture of mainsheet, boom and traveller, isnt the knot on the wrong side of the block ?

    • Admin on July 6, 2016 at 5:35 pm

      Hi Rob
      Nice pick-up. Yeah, it’s better to have the knot on the other side.
      Old photo – will have to update it.

  2. Antony on September 3, 2016 at 5:17 am

    Hello! Love your website, keep it going!

    Have you got any tips on what to do with the mainsheet so that it doesn’t get caught on your feet or on the hiking strap?

    • Admin on September 6, 2016 at 5:30 pm

      Hey Antony
      Thanks for your kind words!
      I think we all have that issue from time to time. I try to tidy up when on a downwind run. Bit hard to do when you are going upwind and hiking, but when sailing downwind it can be a good time to get things organized in the cockpit.
      Maybe some other readers can offer their advice??

  3. John Harding on October 16, 2017 at 3:31 am

    I have a question about the main sheet cleat and block. I just got my Laser and it came with a funny cleat attach to the block. The block has a one way option but the way the cleat is mounted to the block its very hard to use. What angle should the cleat be at relative to the main sail going around the block. I upgraded from a sunfish and it’s block was mounted to the hull and did not flop around like this one does.

    • Admin on October 16, 2017 at 5:23 pm

      Hi John
      Thanks for your question.
      It’s a bit hard to know exactly the type that you have. The one I sail with does not have the cleat attached to the block – rather it has a ratchet block with side-deck cleats. The block is held in a vertical position using a spring at the base. This way, the block does not fall over, and the mainsheet comes out and into the cleats mounted on the deck at a nice angle. This seems to work well, so if you don’t have this setup, you might want to change it out.

  4. Nick on July 25, 2021 at 4:45 am

    Hello, I was wondering if you knew how the laser mainsheet block is held in place from inside the hull?

    thanks, nick

    • Admin on July 26, 2021 at 9:38 am

      Hi Nick
      I have not had the need to unscrew the mainsheet block/hiking strap attachment, so I’m not 100% sure how it is attached underneath the deck.
      Some people think that the screws are simply screwed into the deck as the fibreglass is quite thick here. Others think that there is an aluminum backing plate that the screws screw into to provide the extra strength needed.
      Please have a look at this thread for some more information.
      All the best.

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