Redoing the main sheet block system

Quick starting note:  I am a COMPLETE NOVICE at rigging so if anyone reading spots anything egregious please let me know!

This is what my old block system for the main sheet looked like (non-sailor note: the main sheet is the line you use to control the position of the boom)



The guys who redid my standing rigging told me that it was pretty bad, and recommended redoing it as it was attached to just one bail on the boom (a bail is a metal hoop).

Me being me, I put this off and didn’t do anything about it, until on the sail home yesterday the top block in the picture there had two of its wheely things (not sure what they are called) explode. In a mighty 4 knot wind. Hmm.

Here you can see where the wheely things were supposed to be but are not any more.



Maybe I can streamline my maintenance/replacement list by just waiting until stuff explodes, now there is an idea!

To replace this, I used a bunch of blocks I had found in the boat when I bought it, and had no idea what they did. I think the PO was planning to do this anyway, since I had all the right stuff for it and had to buy nothing extra, which is always lovely.

First, I mounted a block to each bail



So that is 3 blocks.

Then I added a triple-block (again, I think it’s actually called something else) to the traveller, and tied off the other end of the sheet to the same shackle.



Then I ran the mainsheet through everything, following this diagram


from the Harken website here

Its a good resource for complete novices.

This is what it looked like



Apparently it’s a 5:1 system. I gave it a few experimental pulls and it seemed to work well, EXCEPT now the bloody main sheet (this is the line) isn’t long enough to swing the boom all the way to the side! The furthest I can get out is somewhere between a beam and a close reach! Oh well. Ughhhhhhh.





  1. Mechanical advantage = tons of line. And I want to call that triple thing a snatch block, mostly because it makes me giggle.

    • I think you may be right! I’m trying to come up with a joke about a snatch block being my current terrible haircut but it’s not flowing

      • snatch block is a block that opens so you can capture a line without having to put the end through the block, such as a loaded sheet.

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