Fully Battened Main With Flattener and Cunningham, Masthead Rig.

This discussion reminded me I have a simple Cunningham set up onboard but can’t remember when I last used it.

When the wind gets up I typically just add more halyard tension and pull a bit more on the backstay. When would I be advised to start pulling on the Cunningham?
After the halyard. On a typical sail it does more on the bottom ⅓ than the halyard does.
 
After the halyard. On a typical sail it does more on the bottom ⅓ than the halyard does.
No Cunningham on my mainsail, but more tension on the outhaul flattens the bottom part of the sail and is my last step before I put the first reef in. It reduces heel and if the wind increases, the reef again reduces heel and speed typically remains the same
 
Increasing luff tension is about more than flattening the sail. It stops the fullness being blown back towards the leach reducing drag, it also promotes twist depowering the top of the mainsail and if your rig is structured right it will also induce mast bend , flattening the sail, pulling the fullness forwards and promoting more twist. That's how dinghies, small keelboats and racer like Flaming's get away without reefing
 
Sorry, maybe clumsily phrased, not dissing your boat. What happens on a bendy fractional rig won't always happen on a solid masthead rig. With the traditional forum thread drift I will have to go back and see what you actually wanted! 😁
 
Use flattened as a mini reef. Increasing luff tension when windy changes the sail shape in potentially beneficial ways. Flattening the sail and bringing the fullness forwards reduces the drag and gives forwards motion with less healing, more noticeable in bendy rigs but still relevant in masthead flagpole. I think, but wouldn't swear to it that tensioning the cunningham has a different effect to tensioning the halyard because you are not moving the rest of the sail. Not relevant as not sailing?. I am no saint as far as giving up and motor(sail)ing to windward but surely the magic of sailing is the impossible thing of using the power of the wind to sail INTO the wind. Paper bags go off wind quite nicely
 
That's how dinghies, small keelboats and racer like Flaming's get away without reefing
On my Phantom I would ram the kicking strap hard down to get a hard leech. If one did not get the boom down almost to the deck it would hardly sail to windward. The boat would sail off the leech & the woolies meant nothing. Same with a Laser
On a cruiser I have found only slight leech adjustment can make a big difference to balance & speed
Up wind If the leech is too tight my aries sometimes keeps luffing. Ease the clew & the luffing stops & the boat sails a straight line.
 
Still seems like you shouldn't have to go gangbusters on a winch just to get it up without getting the sort of tension you want in 12kts.

We once had this on Dad's old boat which had ball bearing batten cars on a track. I went up the mast in the end and found a little nick in the track just short of the top. God knows what had caused it, but a few minutes with a file and all was good again. Have also sailed another boat where the splice on the halyard shackle was starting to get into the sheave at the top, and the extra thickness was jamming things up.
I wonder if the sheave is level with or hardly above the black band so that for the last 50mm or thereabouts the halyard is just pulling the sail towards the mast or at too shallow an angle to lift the sail effectively?
 
On my Phantom I would ram the kicking strap hard down to get a hard leech. If one did not get the boom down almost to the deck it would hardly sail to windward. The boat would sail off the leech & the woolies meant nothing. Same with a Laser
On a cruiser I have found only slight leech adjustment can make a big difference to balance & speed
Up wind If the leech is too tight my aries sometimes keeps luffing. Ease the clew & the luffing stops & the boat sails a straight line.
Trimming out your weather or lee helm with the main leech is definitely a thing on Chiara.
 
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