Just want to add my thanks for this really illuminating presentation. The explanation of backwinding alone has transformed my understanding of that issue.
Thank you. Must admit to having spent some time Wednesday backwinded, but I put another reef in and the boat calmed down. Tango knows what she wants, and will pester me until I do it...
This is ‘ridiculously’ great!! Fantastic data & graphics. Brilliant! Will be sharing in comments on other YT videos; hopefully more people will find this. Thank you!
James, very valuable class for really understanding all that stuff. great explanation and compared to most online sailing lessons your is the best !!! thank you and hope, we get some more of your time and teaching Franz Austria
this video is an excellent example of what NASA's Glenn Research Center labels "Incorrect Lift Theory #3". The shame is that the illustrations where flow lines are shown actually give a good indication of the actual lift sources, and at 8:59 for example you can see how jib improves sail drive by keeping flow attached to the mainsail and improving the overall redirection of the airmass.
James, your time and knowledge is a great gift to all of us sailers interested in really understanding and looking behind .... goosebumps when your eyes are seeing the reality. ..... thank you , probably the best education i ever got regarding sailing !!! good luck Franz
Thanks for this note. I inspired me to do a new video with better sound that I posted yesterday. Back when those slide decks were put up I was just using a cheap USB microphone. I didn't expect the slides to get much attention.
Hi James. Thanks for this, I have just discovered this video. Instead of reefing the mainsail, would a smaller jib not reduce the backwinding on the main? What I am noticing on my masthead rig is to reduce jib size and twist off the top of the mainsail. Your feedback would be appreciated
A reefed jib will reduce back winding the main. However, it will not help moving the center of effort forward to counteract hull forces rounding the boat up. I put two reefs in the main before rounding up my 110% jib. One exception might be if you had a huge jib out. I would reduce it to about 100% first, or better, drop it and get a smaller jib out.
Amazing! Great work!! But your simulation result holds true when sail is rigid, while it is actually not. So Bounolli theory does not apply here. What really works is just the component of direct force from wind blowing.
Bernoulli's relationship applies to any moving fluid across any surface, even a flag flapping in the wind. The pressure differentials do cause the sails to change shape, so the simulations try to capture the shape at the sails when in use.
Really interesting and non intuitive effect of the mainsail on the jib air flow and pressure. One would think that the jib would be unaffected by a sail aft of the wind.
You're right, it is not intuitive. Even more unexpected to me is the effect the jib has on the air flow ahead of the jib itself. Pretty amazing machines we sail.
Just want to add my thanks for this really illuminating presentation. The explanation of backwinding alone has transformed my understanding of that issue.
Thank you. Must admit to having spent some time Wednesday backwinded, but I put another reef in and the boat calmed down. Tango knows what she wants, and will pester me until I do it...
This is ‘ridiculously’ great!!
Fantastic data & graphics.
Brilliant!
Will be sharing in comments on other YT videos; hopefully more people will find this.
Thank you!
Thanks. Appreciate the posting. Not many sailors find these videos.
@@jamesconger8509 You’re welcome James.
Maybe adding new or modifying existing hashtags might assist people to find the series?
All the best!
This has helped my understanding of a jib immensely. Thank you.
James, very valuable class for really understanding all that stuff. great explanation and compared to most online sailing lessons your is the best !!! thank you and hope, we get some more of your time and teaching Franz Austria
this video is an excellent example of what NASA's Glenn Research Center labels "Incorrect Lift Theory #3". The shame is that the illustrations where flow lines are shown actually give a good indication of the actual lift sources, and at 8:59 for example you can see how jib improves sail drive by keeping flow attached to the mainsail and improving the overall redirection of the airmass.
www.grc.nasa.gov/www/k-12/airplane/wrong3.html for those interested.
This is awesome! If you make more of these my only reccomendation would be to add lines to show the no-sail zone. 😀
Thanks!
James, your time and knowledge is a great gift to all of us sailers interested in really understanding and looking behind .... goosebumps when your eyes are seeing the reality. ..... thank you , probably the best education i ever got regarding sailing !!! good luck Franz
Thanks for the kind words. Fair winds.
What an amazing piece of work.
Thank you.
It would be great if you could take a look at the questions I sent to your yahoo email account.
man recorded a sailing tutorial through a conch shell, that’s dedication
Thanks for this note. I inspired me to do a new video with better sound that I posted yesterday. Back when those slide decks were put up I was just using a cheap USB microphone. I didn't expect the slides to get much attention.
Hi James. Thanks for this, I have just discovered this video. Instead of reefing the mainsail, would a smaller jib not reduce the backwinding on the main? What I am noticing on my masthead rig is to reduce jib size and twist off the top of the mainsail. Your feedback would be appreciated
A reefed jib will reduce back winding the main. However, it will not help moving the center of effort forward to counteract hull forces rounding the boat up. I put two reefs in the main before rounding up my 110% jib. One exception might be if you had a huge jib out. I would reduce it to about 100% first, or better, drop it and get a smaller jib out.
Amazing! Great work!!
But your simulation result holds true when sail is rigid, while it is actually not. So Bounolli theory does not apply here. What really works is just the component of direct force from wind blowing.
Bernoulli's relationship applies to any moving fluid across any surface, even a flag flapping in the wind. The pressure differentials do cause the sails to change shape, so the simulations try to capture the shape at the sails when in use.
Really interesting and non intuitive effect of the mainsail on the jib air flow and pressure. One would think that the jib would be unaffected by a sail aft of the wind.
You're right, it is not intuitive. Even more unexpected to me is the effect the jib has on the air flow ahead of the jib itself. Pretty amazing machines we sail.