Thanks. I wish I could remember from whom I learned the trick of rolling up the jib to attach and detach the pole. Makes life so easy, especially with the ring to hook to.
@nedhogan97383 ай бұрын
It would be interesting to compare your two foil model to a single large foil at the corrected angle and see how much bigger a single foil has to be to generate exactly the same force.
@jamesconger85093 ай бұрын
It has been a decade, but I remember doing that comparison for the upwind case. The result was a small advantage for the two sail configuration, on the order of 2%. I think versatility in varying wind conditions is the larger factor in why the sloop is so popular, not outright performance.
@stillwatersailor6654 ай бұрын
no usa inland lakes
@leetheflea2284 ай бұрын
Awesome video!
@petecapri40545 ай бұрын
Fantastic video! I’d always wondered why the valley bottoms were so flat
@RAD2LTR6 ай бұрын
Very cool to see such a huge fleet of the Birds racing. I couldn't see mine (#22 Hummingbird), but it might have been out there. I saw her sister Bird #5 "Falcon" so that is pretty cool. Falcon was lost in '89 during the Master Mariners race off Angel Island. When this film was done, there was only one missing Bird, #1 that was lost in 1922. Now there are 19 of the original 26 built, 15 of those are likely seaworthy, with one nearly there, another needing a few rotten planks replaced but in otherwise decent shape. The other two need full rebuilds.
@amitchakraborty17577 ай бұрын
Such a great video. Really well balanced and very useful. Thank you.
@skuznetsov779 ай бұрын
Classy
@ScottR-px3oc10 ай бұрын
Hi Jim. Excellent videos! Thank you for putting them together. I am especially interested, as I have owned J32, Hull #58 for the past 15 years (in VA). Would you happen to have polars for the J32 available?
@jamesconger850910 ай бұрын
The original sales material for the J/32 had a little polar and stability curve in the corners. I can send you a scan of the two pages if you give me your email. It's fun looking at the brochure. Now THAT's a boat I would really like! Note, I never used my data to check the polar - probably should have...
@jamesconger850910 ай бұрын
Actually, I can just share a link to that document on my google drive. Here it is: drive.google.com/file/d/1CPw2C1M46Eh45MbT6IO-qGWXodrkLMdI/view?usp=drive_link
@ScottR-px3oc10 ай бұрын
@@jamesconger8509 Thank you very much, Jim! We sailed today in 12-15, gusting to 20. One reef in the main. She sailed great, and still fast. I’m looking forward to using what I have learned through your videos. One a similar note, how did you rig your control lines for your second reef point. Did you have to add a block/blocks at the mast base, and any additional deck organizers / clutches? Mine is rigged with single line, and as you know, has lots of friction, so I’m curious about your rig.
@jamesconger850910 ай бұрын
@ScottR-px3oc Yes, I added to the mast blocks and had to add another clutch. Here in SF we are almost always on the second reef going to weather and on the first reef downwind, for summer conditions. In the winter, all that sail area comes in handy. Have you ever weighed your boat? Based on my 3D model I estimated Tango's weight at 8300# with full fuel and 50 gal of water.
@ScottR-px3oc10 ай бұрын
Never had her weighed, but I believe the travel lift at the yard I use has a scale. I plan to haul late this year and will check. I have always wondered about the advertised displacement being 10K. Seems like that might be a well rounded theoretical number. Thanks for the reef info. If any pictures are available, I’d be interested. Would you be interested in exchanging emails to share J32 info, and/or do you know of a J32 forum (I do not). Cheers@@jamesconger8509
@sidewinder163911 ай бұрын
Thank you so much! This is the first time I really undestand it
@fatpatridesagain11 ай бұрын
Hi.... I enjoyed your two Transpac videos as I, with friends and family, sailed my parents Columbia 36 Winsome from Seattle to Hawaii and return the summer of 73. We must have crossed paths as we stayed for two weeks at the Hawaii Yacht Club during the finish of Transpac in the same slip you stayed in. With the rudder problems you had we probably had left for Hanalei Bay by the time you finished. Great memories but hard to believe that was 50 years ago...Pat
@Masus04 Жыл бұрын
Fantastic Series, best analysis and explanation I've seen so far! Is there any chance you could look at other types of foresails like asymetric spinnakers and compare them to wing on wing?
@Masus04 Жыл бұрын
Another interesting question would be how different trimm options affect the pressure and speed differences. E.g. powering & depowering.
@jamesconger8509 Жыл бұрын
Thanks. I'm going to pass on doing other sail configurations. If I were in the sail business, the work would be worth it, but I have just been doing all this out of curiosity.
@MoneyPitBoating Жыл бұрын
Solid info! Thanks!
@tommiller8416 Жыл бұрын
Great explanation, thank you!
@brycenew Жыл бұрын
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!
@jamesconger8509 Жыл бұрын
Thanks. Appreciate the posting. Not many sailors find these videos.
@brycenew Жыл бұрын
@@jamesconger8509 You’re welcome James. Maybe adding new or modifying existing hashtags might assist people to find the series? All the best!
@howintesting940 Жыл бұрын
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.
@jamesconger8509 Жыл бұрын
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.
@SailingGoodSpirits Жыл бұрын
How do you run this on 12v power? It runs fine if I use the canakit power supply on the 110, but every converter I try from 12v fails. Anybody have a working one not on 110v? Thanks
@jamesconger8509 Жыл бұрын
I used a little $12 step down converter I bought on Amazon.com without any issues. Wired into my 12v DC panel.
@gemiciengin Жыл бұрын
Really good work. Thanks a lot.
@jamesconger8509 Жыл бұрын
Thanks!
@mintafaith Жыл бұрын
I’ve always been curious about this. Thank you!
@jamesconger8509 Жыл бұрын
Yup, me too. Thanks for the note.
@randomcomment3865 Жыл бұрын
Interesting and nicely presented. Thanks Jim! 🙂
@jamesconger8509 Жыл бұрын
You are welcome!
@shayneyoung4801 Жыл бұрын
So good to see such a good complete approach to explaining how sails work. Great to see someone else goes to these lengths to get real data to correlate to modeled simulations. Love the effort you put in.
@jamesconger8509 Жыл бұрын
Thanks. Kept me off the street for a couple of years.
@billycosta3203 Жыл бұрын
Excelent test to try!! Thank you!
@NitroDirt0602 Жыл бұрын
I simply love it!
@gerryriffle3216 Жыл бұрын
Thanks for the info! Much appreciated 👍
@densamme1752 Жыл бұрын
Thank you very much for this video, as newbie sailor this really helped. I think that a problem for many new sailors like me is that we get to learn the ropes in competition settings and when we start to cruise on our own, many of our learnd behaviors are wrong.
@jamesconger8509 Жыл бұрын
You are welcome. I also held racers in high regard when I started, but after a while you learn that there is a lot more to sailing than upwind - downwind mark rounding. Have fun!
@bill2292 Жыл бұрын
Hi James, Great series on sails! Is there a video 4? Can't seem to find it.
@jamesconger8509 Жыл бұрын
I switched to short topics after #3. Look for the channel 'How Sails Really Work' to see the list.
@voncth5791 Жыл бұрын
thx for the info !
@voncth5791 Жыл бұрын
thx you so much for the information :)
@jamesconger8509 Жыл бұрын
You are welcome!
@voncth5791 Жыл бұрын
@@jamesconger8509 i like how you make the videos, very comprehensive. I am quite new to sailing so i am trying to absorb as much as i can now, the opencpn video was particularly good as sailing electronics normally are quite expensive, i am currently trying out that system but without the screen (at least until i can afford one) i use vnc and my cellphone.
@jamesconger8509 Жыл бұрын
@@voncth5791 Thanks. You might look for an old tablet on ebay. All you really need.
@islandman9619 Жыл бұрын
Thanks for the advice. I love the job ring for the pole. I'm about to go offshore and I have prepared myself with paper charts and a sextant specifically for the reason you mention. Thank you!
@isiaihfox7252 Жыл бұрын
I enjoyed immensely - thank you. Brilliant!!!
@andrewpriest9403 Жыл бұрын
Did you take a close look at the Reynolds numbers and boundary layer conditions? Does the BL remain laminar or does it quickly go turbulent? I would hope it goes turbulent so we can get max AoA. But curious what you have found on that.
@jamesconger8509 Жыл бұрын
These are (technically) all in the turbulent regime, Re way above turbulent transition. Using the word 'laminar' a bit more loosely, like P51 people like to do, boundary layer detachment is put off for quite a while. I think you can see this in the velocity profile 2D slices. That is one of the key effects of the jib on the mainsail, delaying detachment. Pretty cool tech for something developed way back when!
@thomasjohnson8121 Жыл бұрын
This is awesome! If you make more of these my only reccomendation would be to add lines to show the no-sail zone. 😀
@jamesconger8509 Жыл бұрын
Thanks!
@sailawayteam Жыл бұрын
One of the best sail trim video series, very good and balanced package! Now one more with spinnaker 🤩
@jamesconger8509 Жыл бұрын
I'm afraid my asymmetric sits safely in the closet. It's just too busy in the SF Bay to use it short or single handed. Offshore its fine.
@jemtuck1 Жыл бұрын
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
@jamesconger8509 Жыл бұрын
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.
@Fearless-sailing Жыл бұрын
I totally agree about the two independent leech and luff reefing lines. I sail solo or double handed and reefing in 30 seconds is a breeze (no pun intended)
@mr.morgan5643 Жыл бұрын
Hello James, Fantastic video, well done sir!
@jamesconger8509 Жыл бұрын
Thanks!
@mr.morgan5643 Жыл бұрын
Never stop learning! Hope to be sailing soon!!
@hosoiarchives4858 Жыл бұрын
Great shirt where did you get it
@mytube001 Жыл бұрын
When I sail dead downwind, or very close to it, I often opt to sail with the main sheeted in quite hard. This does three things. 1. It allows the main to work "backwards", with attached flow, which causes some heel, but also drives the boat (at least my boat) to about 80 % the speed that I would get with the main fully let out. 2. It lets the jib fill and fly well most of the time. 3. It all but eliminates the risk of a crash gybe, since the main and boom only have a couple of feet of movement, and so provides for a much more relaxed downwind sail. Now, you have to consider that I sail deep inside a rocky archipelago, with winds snaking and twisting around islands and rocks, and the islands and rocks leaving little room for me to choose a convenient point of sail...
@svcyclops Жыл бұрын
Love to learn more about the backwind main. I get back winding in 15 knots but can’t trim the main in more without going above centerline. So do I ease the jib an point lower? Or live with the drag? Second question. You had the wind coming from the beam at the jib luff near deck level. But this is counter to twist in the jib which anticipates winders angles up the mast. Great videos!
@jamesconger8509 Жыл бұрын
Thanks! On your first point, are you having this problem with the traveler all the way to windward? In any case, don't relax the jib to make the main happy. On your second point, I need to move the jib car aft to get the best jib sail shape when sailing downwind. That is particularly true when I have the whisker pole deployed.
@Redmanuka Жыл бұрын
thanks james for your really interesting and informative videos. I am a small catamaran sailor, 8m l x4m w. I am interested to know how your simulation would show the implications of a multihull underwater shape?
@jamesconger8509 Жыл бұрын
The short answer is that I have no idea! I've spent very little time on a cat, and never even considered simulating one. Calibrating the models requires that you spend a lot of time sailing and collecting specific data to compare against predictions, so this is something I won't get to in this lifetime.
@wilfdarr Жыл бұрын
SUGGESTION: you touched every so briefly right at the end, the destination at 160 degrees using two tacks, my question is this: using a polar I understand how to get the fastest heading directly upwind and downwind, there's numerous articles on that point (follow the perpendicular of 0 or 180 to the tangent you find your "no go zones"), but what if your destination is outside the upwind and downwind "no go zone", how do I read the polar to find out what the two fastest headings should be as in your example where wing on wing combined with broad reach is the correct answer? I tried to apply the same logic as the upwind/downwind problem and ended up with really funny answers!
@jamesconger8509 Жыл бұрын
I probably don't understand your question. If the destination is outside the "no go zone", it would seem that you just sail directly to that heading. The problem would then reduce to the best sail trim for that heading/apparent wind angle. What am I missing?
@wilfdarr Жыл бұрын
25:10 you say (and I agree) "So if I want to get someplace that isn't straight down wind, the fastest way to get there is to do part of the journey wing on wing and do the other part [broad reach]." If we were going straight down wind, we'd sail the "bump" on the polar at ~160° to the wind for half and then Jibe and sail the rest at ~200° to the wind (wing on wing for both). But if the destination is at 140, reading the polar, it looks like I should be steering ~120° (broad reach) to the wind to get the best VMG and then tack back at some point (wing wing), but I don't understand how to get this answer from the polar.
@jamesconger8509 Жыл бұрын
I think you can only get one leg at a time of the polar. If yours shows wing on wing, then theoretically you would need to iterate between WoW and different broad reach angles to find the combination that has the shortest time to reach a given destination. A shortcut would be to find the broad reach wind angle on your polar that gives you the best downwind VMG, and then use that plus WoW to make up the composite course. (The published polar for my boat doesn't even show wing-on-wing, as it assumes that I would always put up the spinnaker downwind. )
@wilfdarr Жыл бұрын
@@jamesconger8509 I was afraid you might say something like this. I thought there might be away around it that i was missing, especially where only one wind angle is involved. I know that where multiple wind conditions are forecast navigation apps just "brute force" it, trying hundreds of routes with different sailing angles until they get to the best one.
@wilfdarr Жыл бұрын
"The simulation suggests that... it's optimum to have more curvature on the sails as you let the sails out... but with my mainsail I've got full battons and no matter what I do the sail just doesn't bent that much, so it's not optimum..." Absolutely true, but I'd point out that Though it's not optimum for beam reach sailing, the battons ARE optimized for upwind sailing, which is the worst kind of sailing. Most people don't want to spend all day beating too windward and are therefore OK sacrificing a knot or two on the reach or downwind to get better performance on the upwind.
@jamesconger8509 Жыл бұрын
You are completely right. In general the jib and mainsail design is driven by the close hauled case, which is the most critical. You don't give up much performance using those same sails off the wind. I just found it interesting to see what the "perfect" sail shape would be in all cases.
@bcardarella Жыл бұрын
Would it make sense to a few tell tales to where the slot is on the jib and main to ensure that air is flowing properly? My boat has a very small non-overlapping jib and because of where the clew comes in just an eyeball looks like it is hooking back in to the main. I've been curious if it is a performance issue
@wilfdarr Жыл бұрын
Are you saying "add more tell tales to my jib" or " add tell tales to a jib that doesn't have any"? My opinion is that sails should aways have an abundance of tell tales! Yarn doesn't significantly slow a boat down, but not understanding what the sail is doing well definitely slow you down!
@bcardarella Жыл бұрын
@@wilfdarr I guess more to the jib, as I have the usual ones closer to the luff. Right now I don't have a good way to visualize the flow of the slot. James' videos have really highlighted the performance benefit of getting the slot tuned
@jamesconger8509 Жыл бұрын
I too find it difficult to really see the shape of the slot while sailing. Seems like I want to be off the windward stern about 10 feet past the rail to get the right perspective. It's wet over there!
@wilfdarr Жыл бұрын
@@bcardarella Don't get too hung up on "the slot", think of it more as "the air approaching the mainsail", especially if I understand you correctly and you're main is the driving sail, then the jib is really there more to turn and smooth the air in approach to the main. As for telltale on the leech, Quantum says "Telltales can be used on the leech to indicate flow on a non-overlapping jib. As usual, it is the top telltale that counts. Usually there is only a single telltale in the upper 25% of the leech. Trim too hard or pull the lead too far down (or too far forward) for conditions and that telltale will stall. Twist is essential in a non-overlapping sail so you always want the telltale flying."
@otm646 Жыл бұрын
Incredible information, thank you so much for posting this. We'll make this required coursework for the race boat crew The models do an incredible job at picking up where The Science Behind Sailing leaves off.
@wilfdarr Жыл бұрын
There's an android app called "sail flow analysis" that let's you play with different adjustments, I highly recommend that. It's got some glitches so don't take it as scripture, but it's a really good start to wrap your brain around what's happening in real time.
@jamesconger8509 Жыл бұрын
Thank you.
@AnthonyFrancella Жыл бұрын
Cool video, sad the website doesn't work anymore :(
@jamesconger8509 Жыл бұрын
Sorry. I gave up supporting that years ago.
@gobbledegookydokey2 жыл бұрын
Check also BBN Marine OS for raspberry pi4. Many free and opensource boat software packages preinstalled.
@curomni46322 жыл бұрын
man recorded a sailing tutorial through a conch shell, that’s dedication
@jamesconger8509 Жыл бұрын
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.
@svintheanajones882 жыл бұрын
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.
@jamesconger85092 жыл бұрын
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.
Пікірлер
Thanks! Well done exactly what I needed!
You are welcome. Have fun!
Really like the ring whisker pole attachment idea
Thanks. I wish I could remember from whom I learned the trick of rolling up the jib to attach and detach the pole. Makes life so easy, especially with the ring to hook to.
It would be interesting to compare your two foil model to a single large foil at the corrected angle and see how much bigger a single foil has to be to generate exactly the same force.
It has been a decade, but I remember doing that comparison for the upwind case. The result was a small advantage for the two sail configuration, on the order of 2%. I think versatility in varying wind conditions is the larger factor in why the sloop is so popular, not outright performance.
no usa inland lakes
Awesome video!
Fantastic video! I’d always wondered why the valley bottoms were so flat
Very cool to see such a huge fleet of the Birds racing. I couldn't see mine (#22 Hummingbird), but it might have been out there. I saw her sister Bird #5 "Falcon" so that is pretty cool. Falcon was lost in '89 during the Master Mariners race off Angel Island. When this film was done, there was only one missing Bird, #1 that was lost in 1922. Now there are 19 of the original 26 built, 15 of those are likely seaworthy, with one nearly there, another needing a few rotten planks replaced but in otherwise decent shape. The other two need full rebuilds.
Such a great video. Really well balanced and very useful. Thank you.
Classy
Hi Jim. Excellent videos! Thank you for putting them together. I am especially interested, as I have owned J32, Hull #58 for the past 15 years (in VA). Would you happen to have polars for the J32 available?
The original sales material for the J/32 had a little polar and stability curve in the corners. I can send you a scan of the two pages if you give me your email. It's fun looking at the brochure. Now THAT's a boat I would really like! Note, I never used my data to check the polar - probably should have...
Actually, I can just share a link to that document on my google drive. Here it is: drive.google.com/file/d/1CPw2C1M46Eh45MbT6IO-qGWXodrkLMdI/view?usp=drive_link
@@jamesconger8509 Thank you very much, Jim! We sailed today in 12-15, gusting to 20. One reef in the main. She sailed great, and still fast. I’m looking forward to using what I have learned through your videos. One a similar note, how did you rig your control lines for your second reef point. Did you have to add a block/blocks at the mast base, and any additional deck organizers / clutches? Mine is rigged with single line, and as you know, has lots of friction, so I’m curious about your rig.
@ScottR-px3oc Yes, I added to the mast blocks and had to add another clutch. Here in SF we are almost always on the second reef going to weather and on the first reef downwind, for summer conditions. In the winter, all that sail area comes in handy. Have you ever weighed your boat? Based on my 3D model I estimated Tango's weight at 8300# with full fuel and 50 gal of water.
Never had her weighed, but I believe the travel lift at the yard I use has a scale. I plan to haul late this year and will check. I have always wondered about the advertised displacement being 10K. Seems like that might be a well rounded theoretical number. Thanks for the reef info. If any pictures are available, I’d be interested. Would you be interested in exchanging emails to share J32 info, and/or do you know of a J32 forum (I do not). Cheers@@jamesconger8509
Thank you so much! This is the first time I really undestand it
Hi.... I enjoyed your two Transpac videos as I, with friends and family, sailed my parents Columbia 36 Winsome from Seattle to Hawaii and return the summer of 73. We must have crossed paths as we stayed for two weeks at the Hawaii Yacht Club during the finish of Transpac in the same slip you stayed in. With the rudder problems you had we probably had left for Hanalei Bay by the time you finished. Great memories but hard to believe that was 50 years ago...Pat
Fantastic Series, best analysis and explanation I've seen so far! Is there any chance you could look at other types of foresails like asymetric spinnakers and compare them to wing on wing?
Another interesting question would be how different trimm options affect the pressure and speed differences. E.g. powering & depowering.
Thanks. I'm going to pass on doing other sail configurations. If I were in the sail business, the work would be worth it, but I have just been doing all this out of curiosity.
Solid info! Thanks!
Great explanation, thank you!
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!
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.
How do you run this on 12v power? It runs fine if I use the canakit power supply on the 110, but every converter I try from 12v fails. Anybody have a working one not on 110v? Thanks
I used a little $12 step down converter I bought on Amazon.com without any issues. Wired into my 12v DC panel.
Really good work. Thanks a lot.
Thanks!
I’ve always been curious about this. Thank you!
Yup, me too. Thanks for the note.
Interesting and nicely presented. Thanks Jim! 🙂
You are welcome!
So good to see such a good complete approach to explaining how sails work. Great to see someone else goes to these lengths to get real data to correlate to modeled simulations. Love the effort you put in.
Thanks. Kept me off the street for a couple of years.
Excelent test to try!! Thank you!
I simply love it!
Thanks for the info! Much appreciated 👍
Thank you very much for this video, as newbie sailor this really helped. I think that a problem for many new sailors like me is that we get to learn the ropes in competition settings and when we start to cruise on our own, many of our learnd behaviors are wrong.
You are welcome. I also held racers in high regard when I started, but after a while you learn that there is a lot more to sailing than upwind - downwind mark rounding. Have fun!
Hi James, Great series on sails! Is there a video 4? Can't seem to find it.
I switched to short topics after #3. Look for the channel 'How Sails Really Work' to see the list.
thx for the info !
thx you so much for the information :)
You are welcome!
@@jamesconger8509 i like how you make the videos, very comprehensive. I am quite new to sailing so i am trying to absorb as much as i can now, the opencpn video was particularly good as sailing electronics normally are quite expensive, i am currently trying out that system but without the screen (at least until i can afford one) i use vnc and my cellphone.
@@voncth5791 Thanks. You might look for an old tablet on ebay. All you really need.
Thanks for the advice. I love the job ring for the pole. I'm about to go offshore and I have prepared myself with paper charts and a sextant specifically for the reason you mention. Thank you!
I enjoyed immensely - thank you. Brilliant!!!
Did you take a close look at the Reynolds numbers and boundary layer conditions? Does the BL remain laminar or does it quickly go turbulent? I would hope it goes turbulent so we can get max AoA. But curious what you have found on that.
These are (technically) all in the turbulent regime, Re way above turbulent transition. Using the word 'laminar' a bit more loosely, like P51 people like to do, boundary layer detachment is put off for quite a while. I think you can see this in the velocity profile 2D slices. That is one of the key effects of the jib on the mainsail, delaying detachment. Pretty cool tech for something developed way back when!
This is awesome! If you make more of these my only reccomendation would be to add lines to show the no-sail zone. 😀
Thanks!
One of the best sail trim video series, very good and balanced package! Now one more with spinnaker 🤩
I'm afraid my asymmetric sits safely in the closet. It's just too busy in the SF Bay to use it short or single handed. Offshore its fine.
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.
I totally agree about the two independent leech and luff reefing lines. I sail solo or double handed and reefing in 30 seconds is a breeze (no pun intended)
Hello James, Fantastic video, well done sir!
Thanks!
Never stop learning! Hope to be sailing soon!!
Great shirt where did you get it
When I sail dead downwind, or very close to it, I often opt to sail with the main sheeted in quite hard. This does three things. 1. It allows the main to work "backwards", with attached flow, which causes some heel, but also drives the boat (at least my boat) to about 80 % the speed that I would get with the main fully let out. 2. It lets the jib fill and fly well most of the time. 3. It all but eliminates the risk of a crash gybe, since the main and boom only have a couple of feet of movement, and so provides for a much more relaxed downwind sail. Now, you have to consider that I sail deep inside a rocky archipelago, with winds snaking and twisting around islands and rocks, and the islands and rocks leaving little room for me to choose a convenient point of sail...
Love to learn more about the backwind main. I get back winding in 15 knots but can’t trim the main in more without going above centerline. So do I ease the jib an point lower? Or live with the drag? Second question. You had the wind coming from the beam at the jib luff near deck level. But this is counter to twist in the jib which anticipates winders angles up the mast. Great videos!
Thanks! On your first point, are you having this problem with the traveler all the way to windward? In any case, don't relax the jib to make the main happy. On your second point, I need to move the jib car aft to get the best jib sail shape when sailing downwind. That is particularly true when I have the whisker pole deployed.
thanks james for your really interesting and informative videos. I am a small catamaran sailor, 8m l x4m w. I am interested to know how your simulation would show the implications of a multihull underwater shape?
The short answer is that I have no idea! I've spent very little time on a cat, and never even considered simulating one. Calibrating the models requires that you spend a lot of time sailing and collecting specific data to compare against predictions, so this is something I won't get to in this lifetime.
SUGGESTION: you touched every so briefly right at the end, the destination at 160 degrees using two tacks, my question is this: using a polar I understand how to get the fastest heading directly upwind and downwind, there's numerous articles on that point (follow the perpendicular of 0 or 180 to the tangent you find your "no go zones"), but what if your destination is outside the upwind and downwind "no go zone", how do I read the polar to find out what the two fastest headings should be as in your example where wing on wing combined with broad reach is the correct answer? I tried to apply the same logic as the upwind/downwind problem and ended up with really funny answers!
I probably don't understand your question. If the destination is outside the "no go zone", it would seem that you just sail directly to that heading. The problem would then reduce to the best sail trim for that heading/apparent wind angle. What am I missing?
25:10 you say (and I agree) "So if I want to get someplace that isn't straight down wind, the fastest way to get there is to do part of the journey wing on wing and do the other part [broad reach]." If we were going straight down wind, we'd sail the "bump" on the polar at ~160° to the wind for half and then Jibe and sail the rest at ~200° to the wind (wing on wing for both). But if the destination is at 140, reading the polar, it looks like I should be steering ~120° (broad reach) to the wind to get the best VMG and then tack back at some point (wing wing), but I don't understand how to get this answer from the polar.
I think you can only get one leg at a time of the polar. If yours shows wing on wing, then theoretically you would need to iterate between WoW and different broad reach angles to find the combination that has the shortest time to reach a given destination. A shortcut would be to find the broad reach wind angle on your polar that gives you the best downwind VMG, and then use that plus WoW to make up the composite course. (The published polar for my boat doesn't even show wing-on-wing, as it assumes that I would always put up the spinnaker downwind. )
@@jamesconger8509 I was afraid you might say something like this. I thought there might be away around it that i was missing, especially where only one wind angle is involved. I know that where multiple wind conditions are forecast navigation apps just "brute force" it, trying hundreds of routes with different sailing angles until they get to the best one.
"The simulation suggests that... it's optimum to have more curvature on the sails as you let the sails out... but with my mainsail I've got full battons and no matter what I do the sail just doesn't bent that much, so it's not optimum..." Absolutely true, but I'd point out that Though it's not optimum for beam reach sailing, the battons ARE optimized for upwind sailing, which is the worst kind of sailing. Most people don't want to spend all day beating too windward and are therefore OK sacrificing a knot or two on the reach or downwind to get better performance on the upwind.
You are completely right. In general the jib and mainsail design is driven by the close hauled case, which is the most critical. You don't give up much performance using those same sails off the wind. I just found it interesting to see what the "perfect" sail shape would be in all cases.
Would it make sense to a few tell tales to where the slot is on the jib and main to ensure that air is flowing properly? My boat has a very small non-overlapping jib and because of where the clew comes in just an eyeball looks like it is hooking back in to the main. I've been curious if it is a performance issue
Are you saying "add more tell tales to my jib" or " add tell tales to a jib that doesn't have any"? My opinion is that sails should aways have an abundance of tell tales! Yarn doesn't significantly slow a boat down, but not understanding what the sail is doing well definitely slow you down!
@@wilfdarr I guess more to the jib, as I have the usual ones closer to the luff. Right now I don't have a good way to visualize the flow of the slot. James' videos have really highlighted the performance benefit of getting the slot tuned
I too find it difficult to really see the shape of the slot while sailing. Seems like I want to be off the windward stern about 10 feet past the rail to get the right perspective. It's wet over there!
@@bcardarella Don't get too hung up on "the slot", think of it more as "the air approaching the mainsail", especially if I understand you correctly and you're main is the driving sail, then the jib is really there more to turn and smooth the air in approach to the main. As for telltale on the leech, Quantum says "Telltales can be used on the leech to indicate flow on a non-overlapping jib. As usual, it is the top telltale that counts. Usually there is only a single telltale in the upper 25% of the leech. Trim too hard or pull the lead too far down (or too far forward) for conditions and that telltale will stall. Twist is essential in a non-overlapping sail so you always want the telltale flying."
Incredible information, thank you so much for posting this. We'll make this required coursework for the race boat crew The models do an incredible job at picking up where The Science Behind Sailing leaves off.
There's an android app called "sail flow analysis" that let's you play with different adjustments, I highly recommend that. It's got some glitches so don't take it as scripture, but it's a really good start to wrap your brain around what's happening in real time.
Thank you.
Cool video, sad the website doesn't work anymore :(
Sorry. I gave up supporting that years ago.
Check also BBN Marine OS for raspberry pi4. Many free and opensource boat software packages preinstalled.
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.
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.
Thanks very helpful!!!