Search the wreckage of The Flying Osprey in the Wetlands.
The shipwrecks off the shore here are the doomed Third Fleet of Kul'Tiras, burned and sunk by Red Dragons during the last Great War.
The Fleet hailed from Lordaeron, but one ship, an Elvish Destroyer: Flying Osprey, was with it. It was shipping a load of Lightforge Iron and joined the Third Fleet for protection. Ironic that it sunk to the same dragons...
Enough history. The Flying Osprey is wrecked to the south of Menethil Harbor. If you find the Lightforge Iron there, bring it to me.
This chest is waterlogged, and its siding broken. Many claw marks mar both the inside and outside of the chest...as if Murlocs have searched through it and stolen its treasure.
But tucked deep within the chest is a single Lightforge Ingot. Unfortunately, many more will be needed if enough metal to fashion a weapon is to be gained.