perplexus.info :: Science : Come Sail Away

Come Sail Away (Posted on 2007-02-12)

A sailboat race is held on a river that runs directly North to South, with a current of 12 knots. A 25 mile race is held going downriver (south). The first heat is held early in the day when there is no wind. The second heat, also going downriver, is held later, when there is a 12 knot tailwind (from the North). In which heat are the fastest times recorded?

Submitted by Kenny M

Rating: 3.3333 (3 votes)

Solution: (Hide)

The heat with no wind is the fastest. With a tailwind, the fastest sailing speed equals the greater of the tailwind or current speed, which is 13 knots. In other words, at 13 knots speed, you are faster than just drifting, but then your sails are billowing. However, with no wind, you are creating your own 13 knot headwind by virtue of drifting, which, with a bit of tacking, can create boat speeds of much greater than 13 knots in well designed sailboats.

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
Puzzle Answer	K Sengupta	2022-08-30 22:40:58
Faster than the wind ...	Steve Herman	2007-02-19 12:45:56
re(5): solution	Joel	2007-02-15 22:27:30
re(4): solution	Charlie	2007-02-14 23:55:57
re(3): solution	Joel	2007-02-14 20:51:35
re(2): solution	Charlie	2007-02-14 10:06:57
re: solution	Joel	2007-02-14 00:02:12
solution	hoodat	2007-02-13 12:22:21
solution	Charlie	2007-02-13 09:17:02
Not worse	e.g.	2007-02-12 14:23:26

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