Sailing: Newsletter Challenge (06/01/10)

This month's Challenge Question:

You are in a sailing race on a very wide river. On land there is no wind; it is a dead calm. The race is 10 Km downstream, and the river is running 5 Km/ hr. Your opponents decide that to make the best time, they will streamline their boats to the wind and float downstream as fast as they can. You decide on a tacking strategy, sailing back and forth across the river's width. Who wins the race? What is the winning time?

And the Answer is...

ou win the race, because you are sailing upwind. The winning time is: less than the time your opponents took.

When you all cast off you all feel a wind (a perceived wind) in your face as you float downstream. The wind is really the still air, relative to the shore, that you are moving past.

Relative to the river, in which you float, the wind is in your face, and all modern sailboats can sail into the wind--that is, tacking back and forth, up wind. Your path will be much longer than your opponents', but your downstream time will be faster.

Your opponents' maximum speed into the wind, and as measured by the land, will never be faster than the 5 KM/H current. Your speed will be faster by the speed you are able to sail upwind.