Heeling while close hauled - Flying Scot

[ChurchSkiz]

I have a question for the sailing veterans. Was sailing a Flying Scot this weekend. There were gusts around 15 mph while sailing close hauled and the boat started heeling pretty bad. I let the main out as trained and all was fine.

So I know when the sails are all the way trimmed and I'm close hauled that I heel more, and letting the main out rights the boat. I can't understand why though. I would think that letting the main out and it's not luffing would generate more power on the sails and make me heel even more.

My hypothesis was that by sailing close hauled the distribution of power was more concentrated at the center of the boat so it made it tip vs being concentrated over the boat and creating more balance, but this is all conjecture.

I also understood that the jib creates a lot of heeling force which is why some singlehanded sailors don't use a jib in windy conditions, and wondering what effect that has.

Any insight would be appreciated.

[Yellowtulip]

It's a question of angle of attack, meaning the angle of the sail to the true wind. When you let the sail out on a close-hauled course, increasing the angle of attack, the sail is greatly reduced in efficiency, or stalled (but not completely so), therefore it's not producing so much thrust, therefore the boat heels less.

[Suijin]

Originally Posted by ChurchSkiz

I have a question for the sailing veterans. Was sailing a Flying Scot this weekend. There were gusts around 15 mph while sailing close hauled and the boat started heeling pretty bad. I let the main out as trained and all was fine.

So I know when the sails are all the way trimmed and I'm close hauled that I heel more, and letting the main out rights the boat. I can't understand why though. I would think that letting the main out and it's not luffing would generate more power on the sails and make me heel even more.

My hypothesis was that by sailing close hauled the distribution of power was more concentrated at the center of the boat so it made it tip vs being concentrated over the boat and creating more balance, but this is all conjecture.

I also understood that the jib creates a lot of heeling force which is why some singlehanded sailors don't use a jib in windy conditions, and wondering what effect that has.

Any insight would be appreciated.

If you let out the main and it was still not luffing, that means that you were over-trimmed to begin with. When properly trimmed, much of the force of the wind is converted to propulsive power for the boat, with the sail acting effectively as a foil. Over trim the main and most of the force of the wind is just pushing you over.

In general, on any upwind tack, the best trim for a sail is to let it out until it starts to just luff, then bring it back in until it stops luffing. Further refinement can improve the trim, aided by telltales on the sails.

I sailed a Fly Scot single-handed on Barnegat Bay for 15 years. Great little boat that is fun single handed but can also carry a ton of people too.

[svHyLyte]

Originally Posted by ChurchSkiz

...

So I know when the sails are all the way trimmed and I'm close hauled that I heel more, and letting the main out rights the boat. I can't understand why though. I would think that letting the main out and it's not luffing would generate more power on the sails and make me heel even more.

The force vector of the wind transverse to the yacht's center-line that gives rise to healing is reduced as the sail is eased, hence less heeling.

[jeepbluetj]

The wikipedia page on sail forces is pretty good. Overall, remember that except for dead down wind1 a sail is a airfoil, it's pulled not pushed. And closehauled is the point of sail where the lateral force (what is pulling you sideways) is the most. By loosening the mainsheet, you stall the main and remove the force on it.

https://en.wikipedia.org/wiki/Forces_on_sails

[ChurchSkiz]

Originally Posted by Suijin

If you let out the main and it was still not luffing, that means that you were over-trimmed to begin with. When properly trimmed, much of the force of the wind is converted to propulsive power for the boat, with the sail acting effectively as a foil. Over trim the main and most of the force of the wind is just pushing you over.

In general, on any upwind tack, the best trim for a sail is to let it out until it starts to just luff, then bring it back in until it stops luffing. Further refinement can improve the trim, aided by telltales on the sails.

I sailed a Fly Scot single-handed on Barnegat Bay for 15 years. Great little boat that is fun single handed but can also carry a ton of people too.

Thanks. I'm a big guy who wanted to learn on a small boat. I'm really lucky to have the opportunity to sail on the Scots, they are great boats for what I am looking for.

[Moody Mike]

Follow this chart and you can't go wrong. I used to enjoy close hauling on a beam reach getting 8.5 knots but breaking lots of china. Now I ease the main & mizzen still get 8 knots & everyone is more comfortable .

[PNWSalmon]

One thing you can try next time you are in conditions like that is to try and flatten the sails as much as you can. Put on backstay. Put on vang. Tighten the main outhaul. Tighten the Cunningham if your you have one. Make sure the halyard of the main is tight. Then travel down to depower the main and of course, hike out more. You can equally depower the headsail by changing the sheeting angle to flatten it as well as just going to a smaller headsail.

You should find with a more balanced setup and flatter sails you can manage the heel more. Of course you did the right thing to sheet out the main when a big gust hits.

Lots of fun. Keep at it and keep sharing your findings.

[Alan j]

What Suijin said. Also if you let out the main and it didn't luff, you weren't sailing close. hauled. Try heading up next time. Also, you can usually sail higher in the puffs.

[pitlaw]

I sail a Scot. 15 gusting wind is a lot of wind to balance single handed and you probably had your hands full. Spilling air as you did is a good reaction. But sailing tight and flat with vang on, cunningham on, outhaul tight is also a proper set if you can physically balance the forces. The Scot is faster when sailed flat, maybe no more than 5* when racing. At that wind I like about 450lbs in the boat!

It is a great boat. Its in the sail boat hall of fame. Over 6,000 built and with many active fleets nationwide it really holds its value. Lots of fleets to join on the east coast.

[phydeaux]

Suijin and svhylyte are both correct. If easing the main corrects the heel and you still maintain boat speed, you've redirected the lift generated by the mainsail from lateral to forward. You probably got a lot more comfortable and at least a bit faster on the same course.

[subie]

From a fellow newbie. About a month ago I was out sailing with my son on our little 25 footer. Sea was fairly flat with a nice strong wind. I was slow/sleeping at the helm and we had our first knockdown. My son was sitting on the low side, midriff in the seawater and laying nearly on his back he could not get up before I got control again. Was hilarious the look on his face. Felt a bit sheepish afterwards

[Boston Blackie]

Easing the sheet to luff and spill wind is the opposite of stalling, which happens when the sheet is overtrimmed causing wind to no longer flow smoothly around the leeward side of the sail.

[Jetmex]

I sailed a Thistle and learned the hard way that heeling only goes so far before you fill the bathtub with water where we were immediately over run by a summer squall out of no where. Lesson learned, let out the main sheet! Thank god we had help and were only in a small lake.

[FlyingScot]

Here are some documents I have collected that may help you.

Some old polars and a lot of detail. Maybe too much info?
https://www.dropbox.com/s/hw6fxagq5j...Polar.pdf?dl=0

How to from Harry Carpenter himself who can sail these things pretty damn well from what I've seen.
https://www.dropbox.com/s/9p0kwkp9k7...g.pdf.lnk?dl=0

Guide from North Sails.
https://www.dropbox.com/s/5oft1yt0p7...guide.pdf?dl=0