E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Ahead.
The winds aheadi.e., blows in the direction towards which the ships 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.
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To go ahead is to go on without hesitation, as a ship runs ahead of another.