Out on my 8.6 and 85 slalom in lights winds yesterday. Probably at the threshold for that board/sail 12-15kts maybe, I think I did no more than 23knots. I am probably entering at 20 knots

I was trying to gybe around a mark (slalom practice) so waiting for a gust isn't practical, in any case the question is really about when should I be trying to flip the rig in these marginal conditions. If I do it early while I have some speed, the sail is like a handbrake, too late I get backwinded.

Should I be trying to flip normally but concentrated on pushing the sail around to reduce the handbrake effect? I should I delay trying to catch the moment when it will flip by itself, or even be trying to power up the sail clew first for a bit?

It is not clear in my mind what I am aiming for.

That's a big sail to flip late, and try to maintain some boardspeed.
So sheet in hard during entry, which is early, use the added momentum of your sail rake and added power, flip as soon as you fully sheet in, switch feet and sail as you almost hit downwind.
In lighter winds, planing out is not so easy, even for top pros, and especially in dirty water and air.

I think gybing large sails and boards in light winds requires a slightly different approach to stronger winds. None of the how to gybe tutorials mention large sail/board and back winding. I guess they are aimed at people learning, not fine tuning.

Normally I bear off before gybing to minimise the amount I have to turn. But if you bear off in light winds you just lose power and slow down.
You dont want to waste a fraction of a second doing anything in light winds. So dont sail clew first after flipping the rig. It needs to be flipped and providing power.
So
1. Dont bear off and unhook.
2. Back foot just behind the front strap on the other side. On wide boards you need to have it there for leverage.
3. Sheet in a bit to start, but then keep the sail at 90 degrees to the wind as you turn. If you keep sheeted in for longer, when you come to flip the sail thats when it feels back winded as you have further for it to rotate.
4. Switch feet just before heading down wind. The old front foot goes just in front of the back strap, the old back foot goes in front of the front strap. Once there, its not far to move straight into the straps without shuffling the feet back which would waste time.
5. Flip the rig at the apex of the turn. On smaller sails/boards I tend to leave the feet switch and flip a bit later. At 2"11 in the video the track is just the gybe so its easy to see where the flip is.
6. Sheet in, and put the front foot in the strap before hooking in. Sometimes I put both feet in before hooking in. I find if I hook in before putting the front foot in the strap there is more chance of a catapult.

Foiling gybes there is a bigger problem with backwinding due to apparent wind. Seems its better to move the mast to the outside of the turn and rotate the mast around the hips. Its hard to explain in words, I saw a video on youtube with someone explaining it in their lounge, so I'll try and find it. You could adopt that approach, but in a lesser extent.
Since this session in 2018 (time flies) I move my front hand back down the boom a bit to help that, keeping the mast a bit more towards the outside of the turn.

8.5m Ezzy Lion, Exocet S4 80cm wide (the OFO is 57.3cm, so quite a wide tailed board).
BTW, the video software for the speed display in the video seems to be an average of the previous 3-4 seconds to get a smooth reading. The minimum is more likely 5-9 in various gybes. Same for acceleration after the gybe seeming slow.

ps I found the sail got backwinded if I sheeted in for too long, then had to push it against the wind to get it to rotate. On a faster board and sail you would be going faster to me for a given wind strength, so it might be different.

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PhilUK said..
I think gybing large sails and boards in light winds requires a slightly different approach to stronger winds. None of the how to gybe tutorials mention large sail/board and back winding. I guess they are aimed at people learning, not fine tuning.

Normally I bear off before gybing to minimise the amount I have to turn. But if you bear off in light winds you just lose power and slow down.
You dont want to waste a fraction of a second doing anything in light winds. So dont sail clew first after flipping the rig. It needs to be flipped and providing power.
So
1. Dont bear off and unhook.
2. Back foot just behind the front strap on the other side. On wide boards you need to have it there for leverage.
3. Sheet in a bit to start, but then keep the sail at 90 degrees to the wind as you turn. If you keep sheeted in for longer, when you come to flip the sail thats when it feels back winded as you have further for it to rotate.
4. Switch feet just before heading down wind. The old front foot goes just in front of the back strap, the old back foot goes in front of the front strap. Once there, its not far to move straight into the straps without shuffling the feet back which would waste time.
5. Flip the rig at the apex of the turn. On smaller sails/boards I tend to leave the feet switch and flip a bit later. At 2"11 in the video the track is just the gybe so its easy to see where the flip is.
6. Sheet in, and put the front foot in the strap before hooking in. Sometimes I put both feet in before hooking in. I find if I hook in before putting the front foot in the strap there is more chance of a catapult.

Foiling gybes there is a bigger problem with backwinding due to apparent wind. Seems its better to move the mast to the outside of the turn and rotate the mast around the hips. Its hard to explain in words, I saw a video on youtube with someone explaining it in their lounge, so I'll try and find it. You could adopt that approach, but in a lesser extent.
Since this session in 2018 (time flies) I move my front hand back down the boom a bit to help that, keeping the mast a bit more towards the outside of the turn.

8.5m Ezzy Lion, Exocet S4 80cm wide (the OFO is 57.3cm, so quite a wide tailed board).
BTW, the video software for the speed display in the video seems to be an average of the previous 3-4 seconds to get a smooth reading. The minimum is more likely 5-9 in various gybes. Same for acceleration after the gybe seeming slow.

this is great thanks

The sail flip can be tricky in all cases where you're coming in faster than windspeed. If you let the back hand go whilst bearing away the sail just sits there. It obviously gets harder with larger sails as you have more area to rotate without the assistance of the apparent wind and secondly, you can easily exceed windspeed.
You can create some degree of apparent wind on the sail by rotating the rig around you, almost waving it like a flag. After initiating the turn and laying the sail into the turn, rotate and snap it back across you before releasing the back hand and then snapping it back in front of you as you do the grip change. This will help the clew to flick around.
This video is with smaller sails at higher windspeed, but the problem is similar. I'm coming in at ~ 30kts with true windspeed of ~20kts. Watch how the mast is swung around during the turn.

Light winds, YOU actively flip.
Higher winds, you can allow the wind to do the work.

That's good advice from jetlag. Actively pushing the sail when slightly back winded works but can slow the board to a stop.

You push with the mast as the leading edge, the sail tucked behind completely free of wind. There is no backfiring, you you immediately pump on the new side.

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racerX said..
Out on my 8.6 and 85 slalom in lights winds yesterday. Probably at the threshold for that board/sail 12-15kts maybe, I think I did no more than 23knots. I am probably entering at 20 knots

The problem you face is that you have to slow down so much before flipping the rig that you come of the plane if you want to do a normal rig flip without getting backwinded. In 12 knots wind, your board speed dead downwind would have to be below 12 knots, or flipping the sail normally will act as a handbrake.

In the two movies above from PhilUK and Jetlag, the speed drops far enough both times. Jetlag jibes in about 20 knots, and even the best jibes on flat water usually show speed drop to 15-17 knots. So the apparent wind during the sail flip is close to 0, and he may even have a few knots of apparent wind from the back.

To figure out how to flip the rig while going downwind with a board speed that's higher than the wind speed, look at the heli tack. It has to deal with exactly the same problem: flipping the rig with apparent wind coming from the front of the board. The key is to slice the sail forward neutrally, and then use the apparent wind from the front to flip the sail. Basically, you let the wind from the front catch the front of the sail and push the mast back on the new side to get the sail to clew first, and then let it catch the clew to complete the flip. You can see a very similar sail movement (the first part to letting the wind catch from the front) nicely in some flakas, for example at 1:42 in this movie: ?t=102

Very common problem in foiling, Sam Ross :

Lead the flip with the mast moving forward.. Requires a strong, but partial laydown first. Actual flip is started with a strong pull back on the boom, almost forcing, but really allowing sail flip. Sheet in and mini pump immediately.

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powersloshin said..
Very common problem in foiling, Sam Ross :

Agreed.
There is also a video of Nick Dempsey, who was quite good at gybing large sails in light winds, being Olympic silver medallist.
In his 3 key tips he doesnt mention back winding and how to overcome it, but you can see that he is doing the same as Sam Ross, although in my screenshots Nick has already switched feet.