A beam could also be used to provide impulse by directly "pushing" on the sail.

The depression effect on the sail is second order, and therefore negligible.

Forces on the sail do not contribute fully to the advancement of ship.

There are no eddies (dead zones) created on the sail.

Instead of shadows, bright lights sparkled up on the sail.

We do have a big pirate on the sail, but it's been nice working with Disney.

Solar weather also has major effects on the sail.

When the race begins, the boys are allowed to blow on the sail to propel it forward.

The weight of the wind on the sail will push her down into the step and hold her there.

And what's worse, the jets will impinge back on the sail.