Turning block at throat halyard upside down

[dbybe]

I happened across the upside down turning block at the mast while working on a twisted peak halyard.  The pulley should be at the bottom so that the halyard turns around the pulley.  This fitting is riveted in place.  I have not used rivets before but am thiIMG_2400.pdf nking sheet metal screws might be too light for the load on this fitting.  Any suggestions?

[bruce]

Looking at the photo, I see the throat halyard with the red tracers runs below the sheave on the cheek block attached to the mast. Not sure what the halyard is running on, a shackle pin or becket? Not right as you say, lots of friction.

The first thing to try is undo the halyard at the throat gooseneck slide or the cleat on the cabin top and run the halyard correctly through the cheek block, over the sheave. If the halyard runs freely without chaffing on the block you should be good to go. I can't tell from the photo, but the original cheek block may have been replaced with a shackle block that's not appropriate. Post a close-up photo if you continue to have problems.

I'm not a fan of rivets, and would tap the mast and use machine screws, or a through bolt if I felt the load required it. That said, drilling out rivets and installing new ones isn't that hard.

Com-Pac sources the spars and stock fittings from Dwyer Mast (see first link). The cheek block used for the throat halyard was a DH908. Four machine screws would be fine IMO. I would expect the pin of the DH908 would have been above the sheave in the original installation.
https://cpyoa.com/forum/index.php?topic=11288.0
https://dwyermast.com/cheek-block-dh908/

[bruce]

If rerouting the halyard works, but the halyard falls off the sheave, and you don't want to remount or replace the block, then adding a freestanding keeper could work.

A length of 1/2" thin SS or aluminum bar stock, with a leg to mount along the mast above the block, a perpendicular leg to offset the keeper to the right height, and a third leg running tight above but clear of the sheave would keep the halyard in place. Double sided tape, for mounting auto trim for example, would work fine for adhering to the mast, no load involved, if you didn't want to add fasteners.

[dbybe]

Yes that cheek block is the one that was used. The halyard was turning 180 over the pin rather than the sheave.  Flipping it over made a huge difference. I ended up using rivets.  We will see how they hold up. Now a rivet gun and extra rivets are standard tool kit items.