The set of the sails ...

"The set of the sails" ?  A pretty strange header...

Well, it refers to this :

Winds of Fate

One ship drives east and another drives west
With the selfsame winds that blow.
'Tis the set of the sails
And not the gales
That tells them the way to go.

Like the winds of the sea are the ways of fate,
As we voyage along through life:
'Tis the set of the soul
That decides its goal,
And not the calm or the strife.

Ella Wheeler Wilcox