Harken 6:1 Block Mainsheet running off block issue.

I think this may be a rope sizing issue (I'm using 1/2") but whenever I sheet in hard and try to go block to block my rope wants to jump out of the pulley in the block.

When I don't have any strain on the rope it seems to go block to block just fine, but when I'm sailing and try to sheet in hard and go block to block, my rope jumps off the pulley and makes it very difficult to sheet in any further. Do I have the rope run wrong in the block? Rope size too big? I've tried looking online and doing it several ways with similar results.

Here are 2 pics of the issue.

In this pic I'm showing whats happening when I'm sheeting in with tension on the rope how the rope wants to jump off the pulley.
https://photos.app.goo.gl/3n9DNb5AL9u5kMqw9

In this pic shows how it looks without any tension.
https://photos.app.goo.gl/vmzR2aKAkKqPNGur8

1/2" is too big for the 6:1 setup. It looks like your mainsheet isn't sitting in the groove and that's the problem. Use a 3/8" (9mm) mainsheet and you should be good to go.

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H16 2002 "Islands" Sail No. 107432

Hard to tell exactly from your photos, but...

You may want to double check your reeving

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1984 H16 "Mister Rogers"
1984 H14 "Sundays"
2000 H20 "Jet"
Sheet In, Max Out

Your main sheet should run around the center sheave (arrow 2) after coming out of the block's cam cleats (arrow 1).

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Tim
84 H16
82 H16
87 H14T
Tortola Sails: 115222
Blue Prism Sails: 88863
Clearwater, FL

Thanks for the input. It was 2 issues, rope sizing and the way I routed the rope in the blocks. The diagram was very helpful.

What threw me off was even when routed properly my 1/2 rope would jump out. Going to 3/8 solved that issue. Then I was able to sheet in with the rope routed properly without it jumping out.

Appreciate the help!