What is "gaff-rigged"

Usage examples of "gaff-rigged".

Alex sat back in his rocker, listening to the chief, and admiring the pretty little cove filled with sturdy-looking lobster boats, and small gaff-rigged sloops, and catboats riding at their moorings.

Halice had been almost unbearably smug when Allin had found a fourth pirate ship, even if it was only a gaff-rigged single master.