Better sail shape on a reefed mainsail - F21

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newt2u
Posts: 186
Joined: Wed Sep 11, 2019 11:24 am
Location: UK

Better sail shape on a reefed mainsail - F21

Post by newt2u »

I came across this video today https://www.youtube.com/watch?v=zUJ_eQU6z5Q and as I have Rockin in the front yard for the winter decided to implement a detachable outhaul that can be used on any clew cringle, when reefed, as per the video. My current outhaul is at the mast so to make this practical I needed to replace and extend the current outhaul line and bring it back to the cockpit.

The first problem was removing the 4:1 tackle in the boom to measure the line length required. This was achieved by undoing a bolt through the boom on which the forward block is attached, not easy due to stainless/aluminium corrosion. Then the tackle could be pulled out from the aft end of the boom. Note that I used two tracer lines to get it back in. One on the block and one on the tail, as the exit in different holes in the boom. The rear of the tackle is attached to a wire line and D shackle normally fixed to the main clew.
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To bring the line back to the cockpit I added a spinlock jammer, a new fairlead and a block on the kicker deadeye. The final sheave is fixed in the forward end of the boom and from there the line goes down to the mast base and back. I decided to route the line diagonally beneath the other four lines from forward, because I already have 5 jammers on each side of the cockpit and space is tight (the 5th jammer is for lowering the keel).
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Total cost £21, £4 for the hook and £17 for a 10m offcut of 8mm line, the other parts I had in my bin. I'll post back when I have tested this out next season.
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Rockin - F21 twin drop keels - located Milford Haven, Wales

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newt2u
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Location: UK

Re: Better sail shape on a reefed mainsail - F21

Post by newt2u »

There seem to be two approaches for the Cunningham, firstly to ignore it and tension the luff with the halliard and winch. Alternatively I could use the 1st reef as a Cunningham and the second reef line in the first reef point, n.b. I have never used the second reefing point. I wonder, Is there any need for a Cunningham with a two speed winch and halliard?
Rockin - F21 twin drop keels - located Milford Haven, Wales

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newt2u
Posts: 186
Joined: Wed Sep 11, 2019 11:24 am
Location: UK

Re: Better sail shape on a reefed mainsail - F21

Post by newt2u »

Amazingly, after quoting 4-5 day delivery on the rope, it arrived today. So that's another job complete. I am still interested in people's views on the Cunningham.
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Rockin - F21 twin drop keels - located Milford Haven, Wales

unfetteredalexandria
Posts: 118
Joined: Sun Feb 22, 2009 1:57 pm

Re: Better sail shape on a reefed mainsail - F21

Post by unfetteredalexandria »

I have been using my 2nd reef as the cunningham for many years. When I was racing on a bigger boat, and trimming main, I found that cunningham could tension the luff while letting the leach stay open. Halyard tension tended to close the leach.

I also re-rigged the outhaul to bring it back to the cockpit somewhat similarly to what you have done. I had the cover taken off for the parts of the line that mostly run internal to the boom, which makes for a lot less friction. Also the transition point is outside the boom, which provides a handy visual reference that has more stroke than the movement of the clew itself.

Regarding the video: it's true that if you attach the reefing line coming down from the leach cringle directly to the boom below the cringle, then you can't get much "outhaul tension" once the sail is fully reefed down. But nothing says you have to do that! If you tie it off (or otherwise attach it) aft of the cringle, then you can get quite a lot of horizontal tension. I used to use a figure eight knot rather than a bowline to get a nice tight loop. Now I am using some hardware in the boom track instead for attach points.
1984 round-mast Freedom 25
Western Shore of the Chesapeake

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newt2u
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Joined: Wed Sep 11, 2019 11:24 am
Location: UK

Re: Better sail shape on a reefed mainsail - F21

Post by newt2u »

Thanks for the feedback. I had not considered the friction up the track, but yes the Cunningham would put more tension on the lower part of the sail due to that and I guess it can be significant and give the effect you describe.

As to the comment on the video, yes my attach points are directly below the cringles. I guess they could be moved aft but you would loose the attachment to the boom. I liked the notion of soft shackle and outhaul for an emergency reef but it would mean going to the mast ton change the hook on the tack cringle.
Rockin - F21 twin drop keels - located Milford Haven, Wales

unfetteredalexandria
Posts: 118
Joined: Sun Feb 22, 2009 1:57 pm

Re: Better sail shape on a reefed mainsail - F21

Post by unfetteredalexandria »

Sorry I was not too clear on the point about reefing. I didn’t mean to imply to tie the line off so far aft that you lose a lot of the tension component pulling the crinkle down to the boom. Just a few inches aft of the cringle is enough.
1984 round-mast Freedom 25
Western Shore of the Chesapeake

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