Thanyou for responding Captain. I have watched many of your videos and would like to commend you on your work rate, likeabilty, and the knowledge you have imparted through your work. At no point have I ticked a dislike option, and look forward to your future postings. With regards. Geo.
Captain John, with respect sir, the luff of the sail is presented parallel to the apparent wind, bisecting the airflow. The boom pulled to windward of this then provides two dissimilar environments. One closing and confining, increasing pressure, the other opening, rarefying and increasing flow and therefore decreasing pressure. The sail is a pressure engine, robbing the wind of it's momentum and energy.
The sail, like a flag, has no idea whether the boat is moving or not. When you release the mainsheet on a moving boat the sail is depowered and trails in the resultant of the wind vectors, the apparent wind. As the way comes off the sail progressively turns into the true wind parallel, and the boat, still unpowered, stops.
When you stop a boat, you turn up into the true wind. Or let the boom out to luff the sails to the true wind (i.e. on a close reach when docking or picking up a person in the water). To produce apparent wind , you need to combine true wind with boat speed. Your sails are trimmed to the apparent wind when sailing so that the air will flow smoothly without turbulence from luff to leech.
MOB! That ought to get your attention. Look, any flag on your boat or the wind vane on the top of your mast always indicates apparent wind. We all sail by apparent wind anyway, there is no further sailing information here. Anyone who has attempted to stop their boat will know that when you let the boom align with the apparent wind it produces NO power. It in no way resembles an aerofoil at this stage, rather a sail flapping in the breeze! When approaching a mooring or MOB, aligning initially
lol .. man in all my years i never yet seen anyone who could teach how a one sails against the wind.. they ALways suppose the wind is in back pushing where ya wanna go.. well how about if where ya wanna go is straight against the wind?
It sounds like the daggerboard on the outrigger may be causing a turning moment, much like a wind vane on a barn roof. When the wind strikes the outrigger hull, it pivots around on the daggerboard toward the wind.
Hi Capt John, Are you able to advise me? I have built an outrigger craft with v hull 2ft beam, 2 ft draft and 14ft length. Wind surfer mast. With wind over the outrigger, it luffs up constantly, whereas on the other tack it sails well. I have one swinging daggerboard on the outrigger side of the main hull, in line with mast & rudder. Could the problem be the position of the dagger or that of the mast? This is my first utube contact. Roger F
There's a fourth kind of wind. That's the wind that blows when your Captain is speaking! Actually, I enjoyed your presentation. I've been sailing for a long time, and I found your description of wind effect very knowledgable and helpful. Thanks.
This video will totally changed my sailing habits. For whatever reason, I have always thought the main had to be perpendicular to the apparent wind (or as close as possible). What an eye opener. Oh, and I joined your SkipperTip site too. Thanks!
Hey Captain John!, thanks for posting this video it helped back up the article you sent me. I am starting to understand apparent wind now !, I found your tip about putting the boom parallel to the apparent wind really useful, I will try it out when we race tomorrow night. Thanks again have a good Christmas!
Thanyou for responding Captain. I have watched many of your videos and would like to commend you on your work rate, likeabilty, and the knowledge you have imparted through your work. At no point have I ticked a dislike option, and look forward to your future postings. With regards. Geo.
g1geo1g 3 months ago
Thanks for your very thorough explanation. Perhaps a slight realignment of the wind arrows would be in order.
seasensical 3 months ago
Captain John, with respect sir, the luff of the sail is presented parallel to the apparent wind, bisecting the airflow. The boom pulled to windward of this then provides two dissimilar environments. One closing and confining, increasing pressure, the other opening, rarefying and increasing flow and therefore decreasing pressure. The sail is a pressure engine, robbing the wind of it's momentum and energy.
g1geo1g 3 months ago
The sail, like a flag, has no idea whether the boat is moving or not. When you release the mainsheet on a moving boat the sail is depowered and trails in the resultant of the wind vectors, the apparent wind. As the way comes off the sail progressively turns into the true wind parallel, and the boat, still unpowered, stops.
g1geo1g 3 months ago
When you stop a boat, you turn up into the true wind. Or let the boom out to luff the sails to the true wind (i.e. on a close reach when docking or picking up a person in the water). To produce apparent wind , you need to combine true wind with boat speed. Your sails are trimmed to the apparent wind when sailing so that the air will flow smoothly without turbulence from luff to leech.
seasensical 3 months ago
MOB! That ought to get your attention. Look, any flag on your boat or the wind vane on the top of your mast always indicates apparent wind. We all sail by apparent wind anyway, there is no further sailing information here. Anyone who has attempted to stop their boat will know that when you let the boom align with the apparent wind it produces NO power. It in no way resembles an aerofoil at this stage, rather a sail flapping in the breeze! When approaching a mooring or MOB, aligning initially
g1geo1g 3 months ago
Would be a great video in my Physics project ..
Really appreciate it thank you .. :D
Outbreak95 3 months ago
Awesome, thanks!
DrTTube 9 months ago
really great, clear instruction! thank you!
ranguit 9 months ago
lol .. man in all my years i never yet seen anyone who could teach how a one sails against the wind.. they ALways suppose the wind is in back pushing where ya wanna go.. well how about if where ya wanna go is straight against the wind?
frank0067 9 months ago
Love the videos. Thanks for making them and sharing them.
Pedroskini 11 months ago
Kite Runner,
thanks for your kind comment.
Captain John
seasensical 11 months ago
Captain John, you keep it simple and well illustrated. I enjoy your contribution to the sailing world. Keep up the great work!
Kite Runner
Vancouver, BC
montanabc 11 months ago
Hi Roger,
It sounds like the daggerboard on the outrigger may be causing a turning moment, much like a wind vane on a barn roof. When the wind strikes the outrigger hull, it pivots around on the daggerboard toward the wind.
Captain John
seasensical 1 year ago
Hi Capt John, Are you able to advise me? I have built an outrigger craft with v hull 2ft beam, 2 ft draft and 14ft length. Wind surfer mast. With wind over the outrigger, it luffs up constantly, whereas on the other tack it sails well. I have one swinging daggerboard on the outrigger side of the main hull, in line with mast & rudder. Could the problem be the position of the dagger or that of the mast? This is my first utube contact. Roger F
chindamba1 1 year ago
Good laugh on that one! Thanks for the comments.
seasensical 1 year ago
There's a fourth kind of wind. That's the wind that blows when your Captain is speaking! Actually, I enjoyed your presentation. I've been sailing for a long time, and I found your description of wind effect very knowledgable and helpful. Thanks.
sergeantsailorman 1 year ago
Thanks!!! Great job!!!
BM537 2 years ago
Great explination...Thanks for your help. Keep up the good work
gkel365 2 years ago
This video will totally changed my sailing habits. For whatever reason, I have always thought the main had to be perpendicular to the apparent wind (or as close as possible). What an eye opener. Oh, and I joined your SkipperTip site too. Thanks!
ZipTumbleFast 2 years ago
Hey Captain John!, thanks for posting this video it helped back up the article you sent me. I am starting to understand apparent wind now !, I found your tip about putting the boom parallel to the apparent wind really useful, I will try it out when we race tomorrow night. Thanks again have a good Christmas!
CaptainAhabNZ 3 years ago