The wind's ahead
i.e., blows in the direction towards
which the ship's head points; in front. If the wind blows in the
opposite direction (i.e., towards the stern) it is said to be
astern. When one ship is ahead of another, it is before it, or
further advanced. “Ahead of his class,” means at the head. Ahead in a
race, means before the rest of the runners.
To go ahead
is to go on without hesitation, as a ship runs ahead of another.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894