Regarding your description of weight placement…every boat I’ve ever owned has responded exactly opposite. I sail a “Duck Punt” and it has no rudder. In order to tack you must move your weight forward. I lived on a Flicka that sailed to weather in light air perfectly balanced. I would lean forward slightly to head up, back to fall off. My current Montgomery 15…same thing. In order to come about I shift my weight a bit forward for a smooth tack. I don’t know where your information comes from, but it’s not supported by my real world experience in a variety of different boats. 🤷♂️
Mikka Kittey/Tessa Violet of the sailing world... and I mean that as a compliment. Well done once again. I learn a lot every time I watch another video. Excellent. I need to take notes. Da... thanks!
Thank you for a very informative video. It helped me get into ruderless sailing quick and easily! However, there's an error in the information provided. At around 5 minute mark, you stated that moving your weight aft will cause the boat to head up, and moving your weight forward will cause it to bear off. This is incorrect. It should be the opposite: weight aft = bear off, and weight forward = head up. This is due to the Center of Lateral Resistance (CLR) being moved in relation to the Center of Effort(CE): CLR ahead of CE = weather helm, CLR behind CE = lee helm. (Please note that this effect is subtle on a small dinghy with a planning hull). A more detailed explanation is available in the PDF document "Rudderless Sailing" by Joel Brand.
Heyyo! Love the vid, just wanted to share that the "equal transit theory" is incorrect, as the molecules don't have awareness of one another to both reach the trailing edge at the same time. There are high and low-pressure vectors on the wing/sail, and Breunoulis' Principle is true, just not the equal air molecule idea.
It's best to remember that sails work in a compressible fluid (air) and the hull is in an incompressible fluid. I don't agree with her description of Bernoulli's principle applying to the water flow around the hull as the primary force causing windward or leeward rotation. When speed is low, there is too small of an effect in the water- but that is not true of the wind that is flowing over the sails- at hull v=0, air v=max. The change in waterline length and exposure area of the hull vertically against the water are more significant. This would be better explained if the video included a discussion of center of pressure and the shifting location of the effective center of pressure. When the center of crew mass shifts aft (the rear of the boat), the geometry of the hull forces the center of pressure of the water around the boat to shift aft, and vice versa when the center of crew mass shifts forward towards the bow. Under a constant wind flow and sails slack, the wind drag can be assumed to be fairly evenly distributed across the exposure of the sails, masts, and above waterline hull, and the boat can be rotated and pointed either upwind or downwind to a small degree due to the offset, the eccentricity, between the center of air pressure and the effective center of pressure of the hull against the water, that is the resisting force.
I have heard that a two masted boat such as the Polynesian Hokulea, Not only can initiate, but maintain any long course relative to the wind with sail balance alone: Sheeting the foresail more than the aft. So that windward pivots are checked by more foresail push and leeward, by more aft sail push. Does this work on a sloop? For all courses even downwind and broad reach?
On a 2 masted boat, the ability to sheet in/out each of the sails provides the ability to steer on a long reach. On a sloop both head and mainsail are on a single mast and limits the amount of what can be done with sails alone.
Because you have incorrect explaination of wing lift, so you have incorrect explain of "hull turning, helming". "hull turnning" is effect of drag, not the lift. Google for Arvel Gentry, he explained this a lot.
It’s not just me that thought her understanding of lift was wrong then. The “speed over the top has to speed up to meet the air at the bottom” theory has been scientifically proven wrong so many times. The air is quicker over the top, but the same air does not meet up again at the end of the wing. Also, if it did work as she claimed, the forces would cause the boat to move laterally towards the curved side. Drag affecting rotating makes a lot more sense.
I did as suggested and looked up Arvel Gentry. I downloaded his paper "DESIGN OPTIMIZATION OF INTERACTING SAILS THROUGH VISCOUS CFD " and quickly realized it was not going to help me as it was a specialized accademic paper and you need degree level knowledge to understand it. As a sailing instructor you need a simple explanation to help everyday sailors. Perhaps we just need to go along with observation that heeling to leeward turns the boat into the wind and leave it at that.
Yes there was an article not too long after we released this video adjusting the previous understanding of Bernoulli's principle that someone commented on- we replied and said we were crossing our fingers that others would visit the comment section to read the amendment. Can't edit the video, though :/ Thanks for the comment! -Allison
Brilliant .. if anyone says anything negative about this presentation then ..1 they are not bright enough to to keep up ... or 2 they have their heads up their bottoms contemplating the amount of ink in a marker pen ........ I have been sailing for 50 years I took a lot away here ... and this was informative and really well produced and presented....to boot ...
Regarding your description of weight placement…every boat I’ve ever owned has responded exactly opposite. I sail a “Duck Punt” and it has no rudder. In order to tack you must move your weight forward. I lived on a Flicka that sailed to weather in light air perfectly balanced. I would lean forward slightly to head up, back to fall off. My current Montgomery 15…same thing. In order to come about I shift my weight a bit forward for a smooth tack. I don’t know where your information comes from, but it’s not supported by my real world experience in a variety of different boats. 🤷♂️
I've been "sailing" my whole life, but learned more watching this series of UGA Sailing videos. Thanks so much!
Thanks so much, Thomas! We're thrilled you found them helpful.
Happy sailing,
Allison
You’re videos are my constant go to for our practices and reinforcing what we go over! Thank you!
That means a lot, thank you so much for your comment :)
-Allison
Valuable. Really helpful and very practical. A technique that builds confidence. Tougher with unirig but also works.
Mikka Kittey/Tessa Violet of the sailing world... and I mean that as a compliment. Well done once again. I learn a lot every time I watch another video. Excellent. I need to take notes. Da... thanks!
Thanks Tedd!
-Allison
Thank you for a very informative video. It helped me get into ruderless sailing quick and easily!
However, there's an error in the information provided. At around 5 minute mark, you stated that moving your weight aft will cause the boat to head up, and moving your weight forward will cause it to bear off. This is incorrect. It should be the opposite: weight aft = bear off, and weight forward = head up. This is due to the Center of Lateral Resistance (CLR) being moved in relation to the Center of Effort(CE): CLR ahead of CE = weather helm, CLR behind CE = lee helm. (Please note that this effect is subtle on a small dinghy with a planning hull).
A more detailed explanation is available in the PDF document "Rudderless Sailing" by Joel Brand.
Great video. Thanks for posting. Science aside, everything you say about sailing without putting the “breaks” on, works on the water.
Thank you! Glad you found it helpful!
Allison
Love watching your videos. Nice work. Thanks
Thanks, Gui! Means a lot!
-Allison
Really fantastic teaching! Easy to pay attention
It’s been almost 30 years since I was a student at UGA. Somehow I feel like I’m learning more now!
Heyyo! Love the vid, just wanted to share that the "equal transit theory" is incorrect, as the molecules don't have awareness of one another to both reach the trailing edge at the same time. There are high and low-pressure vectors on the wing/sail, and Breunoulis' Principle is true, just not the equal air molecule idea.
www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/wrong1.html
Brilliant video. Many thanks from a sailing novice.
Excellent explanation! Keep up the great work.
Thanks so much, Reza! Your support means a lot!
-Allison
Excellent video
Really learned so much from this video
Thanks, CJ :) Glad you found it helpful!
-Allison
Great explanation.
This is some great stuff!
Hi John, thanks for the encouragement! Means a lot.
-Allison
This is great! Thanks!
Glad you liked it! Thanks for the support :)
works great for me , good vids thanks, KISS
Thanks, Neil! Glad you are enjoying them. -Allison
It's best to remember that sails work in a compressible fluid (air) and the hull is in an incompressible fluid. I don't agree with her description of Bernoulli's principle applying to the water flow around the hull as the primary force causing windward or leeward rotation. When speed is low, there is too small of an effect in the water- but that is not true of the wind that is flowing over the sails- at hull v=0, air v=max. The change in waterline length and exposure area of the hull vertically against the water are more significant. This would be better explained if the video included a discussion of center of pressure and the shifting location of the effective center of pressure. When the center of crew mass shifts aft (the rear of the boat), the geometry of the hull forces the center of pressure of the water around the boat to shift aft, and vice versa when the center of crew mass shifts forward towards the bow. Under a constant wind flow and sails slack, the wind drag can be assumed to be fairly evenly distributed across the exposure of the sails, masts, and above waterline hull, and the boat can be rotated and pointed either upwind or downwind to a small degree due to the offset, the eccentricity, between the center of air pressure and the effective center of pressure of the hull against the water, that is the resisting force.
Center of effort on sails vs center of resistance on the hull
for all the Rudderless sailing how to videos... this is the only one that actually EXPLAINS its, not just shows it
I have heard that a two masted boat such as the Polynesian Hokulea, Not only can initiate, but maintain any long course relative to the wind with sail balance alone: Sheeting the foresail more than the aft. So that windward pivots are checked by more foresail push and leeward, by more aft sail push. Does this work on a sloop? For all courses even downwind and broad reach?
On a 2 masted boat, the ability to sheet in/out each of the sails provides the ability to steer on a long reach. On a sloop both head and mainsail are on a single mast and limits the amount of what can be done with sails alone.
Because you have incorrect explaination of wing lift, so you have incorrect explain of "hull turning, helming". "hull turnning" is effect of drag, not the lift. Google for Arvel Gentry, he explained this a lot.
It’s not just me that thought her understanding of lift was wrong then. The “speed over the top has to speed up to meet the air at the bottom” theory has been scientifically proven wrong so many times. The air is quicker over the top, but the same air does not meet up again at the end of the wing. Also, if it did work as she claimed, the forces would cause the boat to move laterally towards the curved side. Drag affecting rotating makes a lot more sense.
Concur, drag is the predominant force
I did as suggested and looked up Arvel Gentry. I downloaded his paper "DESIGN OPTIMIZATION OF INTERACTING SAILS THROUGH VISCOUS CFD " and quickly realized it was not going to help me as it was a specialized accademic paper and you need degree level knowledge to understand it. As a sailing instructor you need a simple explanation to help everyday sailors. Perhaps we just need to go along with observation that heeling to leeward turns the boat into the wind and leave it at that.
screen shot!
An aircraft flies due to the many forces involved with conservation of momentum.
Yes there was an article not too long after we released this video adjusting the previous understanding of Bernoulli's principle that someone commented on- we replied and said we were crossing our fingers that others would visit the comment section to read the amendment. Can't edit the video, though :/
Thanks for the comment!
-Allison
@@ugasailing9571 whatever you say.
www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/wrong1.html
Brilliant .. if anyone says anything negative about this presentation then ..1 they are not bright enough to to keep up ... or 2 they have their heads up their bottoms contemplating the amount of ink in a marker pen ........ I have been sailing for 50 years I took a lot away here ... and this was informative and really well produced and presented....to boot ...
Your comment made me giggle- thanks for the lighthearted acceptance of my dying markers! And thank you for the kind words, means a lot :)
-Allison
Of course some of the information is wrong. www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/wrong1.html
Buy some new marker pens!!!! and you are too quick in explaining.
Yep haha not our best pen visibility video, we agree. Whoops!