How a Boat Sails in Apparent Wind

Easy tips for small boat cruising sailors-- http://www.skippertips.com

Category:

Howto & Style

Tags:

• sail trim
• sail shape
• small cruising sailboat
• apparent wind
• sailing wind
• mainsail trim
• basic sailing
• cruising sailboat

[seasensical]

Thanks for your very thorough explanation. Perhaps a slight realignment of the wind arrows would be in order. 

[seasensical]

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]

Kite Runner,

thanks for your kind comment.

Captain John

[seasensical]

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]

Good laugh on that one! Thanks for the comments.

[g1geo1g]

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]

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]

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]

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

[Outbreak95]

Would be a great video in my Physics project ..

Really appreciate it thank you .. :D

[DrTTube]

Awesome, thanks!

[ranguit]

really great, clear instruction! thank you!

[frank0067]

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?