I had a halyard extension fabricated out of alum flat bar, with a fork that slips over the head of the mainsail and is secured with a clevis pin, and a hole in the other end that the hlyd ring attaches to. This keeps the ring in the correct orientation to the main, to allow easy disengagement from the hook when lowering the mainsail.

The rolling and lashing of the excess sailcloth is tough to do cleanly, and it strikes me as mildly damaging to the sail, particularly laminate sailcloths. But unavoidable I guess, and the safety offered by the ability to reef is very valuable on large bodies of water. Downhaul system might need to be modified to attach to the new tack in a fashion that allows it to pull fairly directly.

The sail definitely needs to be modified to include new reinforced tack and clew grommets, as well as 2 or 3 grommets installed to allow a line(s) to be used to secure the excess material. The batten(s) will be parallel to the boom, so not a problem.

Having to drop the main to reef is problematic, considering the conditions you'll be in when it's needed. Keeping the main onboard while keeping the boat into the wind on a lumpy sea in a blow, is a challenge. As is getting it up again, and tidying up, still keeping the bows windward. Would be helpful if you could get to a lee shore to do all this, but that's not often an option.

So the system needs to be thought out, and tested before you need it. It's unlikely you're going to get a really good sail shape reefed, but the substantially reduced sail area is more of a safety feature than a performance item.

If you're looking high wind performance, consider having one built specifically for your boat/mast. I know Jay Glaser has experience with this, and I imagine most of the multihull sailmakers do too. But this option doesn't help you if you're caught out in increasing breeze with your full size main.

Dave

Hey Jeff! Where is Big Marine Lake? I get back to MN most summers, I spend a week or so on Lake Minnetonka, and try to get a sail in with the Fleet 444 guys who often sail on Lake Pepin.