The interruption of blue

The eye is pleased with such a sight
when blue shades alternate.
But on a sailing boat it might
bore when the winds abate.

A consequence of fickle wind
will be to pull down sails
whereby your sailing plans rescind
until more wind prevails.

Or looking closer you detect
a harbour straight ahead
So it is easy to deflect
from sailing then instead.

For then, the boat docked at the pier,
you can enjoy your can of beer.