Single line reefing

[Wight Spirit]

Hi, my Southerly 100 has a strange fitting at the gooseneck. In the photo, you will see two rings where you would normally have ram's horns for reefing the leech of the mainsail. I guess that they are for a form of single-line reefing, but cannot work out how to rig it.
The boom (photos attached) is by Kemp and it has two blocks on the port side and one block on the starboard side. One reefing line emerges from the starboard side of the boom end fitting, marked Reef 1 and one reefing line emerges from the port side of the boom end fitting, marked Reef 2.
I'd be grateful for advice on how to rig the reefing lines. Many thanks!

 

[B27]

There are many variations on single line reefing.
Barton Marine - Tech Info - Sail Handling - Single Line Mainsail Reefing Kit Fitting

https://gallery.harken.com/gallery/a135197e-1b75-4935-98a9-bfda3afd95bb.pdf

Seldén Single Line Reefing Upgrade Pack @Allspars

 

[vyv_cox]

I have small blocks each side of the boom for the clew downhauls. Those rings are an alternative solution.

The system I use is shown here Single line reefing: DIY system. I derived it myself but it was subsequently used by Z-Spars.

 

[Stemar]

When I set up single line reefing on my previous boat, I fitted an eye bolt and nut to give the same effect. I attached blocks to them, so the line came up from the foot of the mast to the reefing cringle on the luff, back down to the block and out to a cheek block on the boom, up to the luff cringle and back down to an eye on the boom. Repeat on the other side for the second reef. I found it necessary to fit a block at the luff cringle, sewn to some tape through the cringle and sewn to a D ring on the other side. If you do this, spend the money for quality ball bearing blocks all the way along to reduce friction.

 

[chris-s]

Hi, my Southerly 100 has a strange fitting at the gooseneck. In the photo, you will see two rings where you would normally have ram's horns for reefing the leech of the mainsail. I guess that they are for a form of single-line reefing, but cannot work out how to rig it.
The boom (photos attached) is by Kemp and it has two blocks on the port side and one block on the starboard side. One reefing line emerges from the starboard side of the boom end fitting, marked Reef 1 and one reefing line emerges from the port side of the boom end fitting, marked Reef 2.
I'd be grateful for advice on how to rig the reefing lines. Many thanks!

Reckon those eyes probably act as fairleads for lines to the luff reefing points. The isomat rigging on our Beneteau has something very similar.