# Sail Ship speed vs. Wind speed

**URL:** <https://boards.straightdope.com/t/sail-ship-speed-vs-wind-speed/535777>\
**Category:** Factual Questions\
**Created:** [April 11, 2010, 10:21pm UTC](https://boards.straightdope.com/t/sail-ship-speed-vs-wind-speed/535777 "2010-04-11T22:21:52Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Simple\_Mind](https://avatars.discourse-cdn.com/v4/letter/s/7cd45c/32.png) [@Simple\_Mind](https://boards.straightdope.com/u/Simple_Mind)\
**Post date:** [April 11, 2010, 10:21pm UTC](https://boards.straightdope.com/t/sail-ship-speed-vs-wind-speed/535777/1 "2010-04-11T22:21:52Z")

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Is it possible that a Sail Ship is running faster than the Wind driving it and if so, why?  
Thanks

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**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [April 11, 2010, 11:41pm UTC](https://boards.straightdope.com/t/sail-ship-speed-vs-wind-speed/535777/2 "2010-04-11T23:41:42Z")

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It can happen, but not if you’re going directly with the wind. The fastest speeds are when you’re going at close to a right angle from the wind direction. Think of how, when you squeeze a watermelon seed, it shoots out faster than your fingers moved together: It’s a similar phenomenon.

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**Author:** ![penultima\_thule](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/penultima_thule/32/3833_2.png) [@penultima\_thule](https://boards.straightdope.com/u/penultima_thule)\
**Post date:** [April 12, 2010, 12:35am UTC](https://boards.straightdope.com/t/sail-ship-speed-vs-wind-speed/535777/3 "2010-04-12T00:35:11Z")

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From: High Performance Sailing, “any boat which runs ‘square’ must necessarily sail downwind at some speed less that the wind’s speed whereas any boat which tacks downwind has no theoretical limit to its speed. Ice yachts, for example, can tack downwind at average speeds many times the wind speed.”

[18ft Skiffs](http://en.wikipedia.org/wiki/18ft_Skiff) which are essentially a sail, rudder, centreboard and human ballast can sail as close as 20 degrees.

[Sailing faster than the wind](http://en.wikipedia.org/wiki/Sailing_faster_than_the_wind)

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**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\
**Post date:** [April 12, 2010, 4:21pm UTC](https://boards.straightdope.com/t/sail-ship-speed-vs-wind-speed/535777/4 "2010-04-12T16:21:29Z")

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Check out [L’Hydroptere](http://en.wikipedia.org/wiki/Hydropt%C3%A8re):

> [@](#):
>
> On September 4, 2009, the Hydroptère broke the outright world record, sustaining a speed of 51.36 knots for 500m in 30 knots of wind.

Googling the name yields many impressive videos.

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**Author:** ![\_Undecided\_Adrian](https://avatars.discourse-cdn.com/v4/letter/_/eada6e/32.png) [@\_Undecided\_Adrian](https://boards.straightdope.com/u/_Undecided_Adrian)\
**Post date:** [April 12, 2010, 9:16pm UTC](https://boards.straightdope.com/t/sail-ship-speed-vs-wind-speed/535777/5 "2010-04-12T21:16:46Z")

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There was a [Straight Dope column](http://www.straightdope.com/columns/read/2908/how-can-racing-yachts-sail-faster-than-the-wind) on the topic in November.

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**Author:** ![Simple\_Mind](https://avatars.discourse-cdn.com/v4/letter/s/7cd45c/32.png) [@Simple\_Mind](https://boards.straightdope.com/u/Simple_Mind)\
**Post date:** [April 12, 2010, 10:17pm UTC](https://boards.straightdope.com/t/sail-ship-speed-vs-wind-speed/535777/6 "2010-04-12T22:17:51Z")

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Thank’s for the Information.