COLONIA DEL SACRAMENTO, Uruguay (AFP) - A sunken English warship, perhaps holding a treasure chest of gold coins onboard, will be raised from its watery grave off the coast of Uruguay after being submerged for some 252 years, a treasure hunter announced.

The "Lord Clive," sunk by the Spaniards in 1763, was discovered by adventurer Ruben Collado in 2004.

Collado announced late Friday he has received permission from the Uruguay government to bring up the remains of the 60-gun privateer from off the coast of Colonia del Sacramento.

The Lord Clive was sunk by fire from the shore as the British and Portuguese tried to bombard and take the city from the Spanish during the Seven-Years War that saw colonial powers square off around the globe. Some 270 people onboard were killed.

The Spanish held Colonia del Sacramento but would eventually have to return the city to the Portuguese under a treaty signed the same year.

The ship, outfitted to wage war for three to four years, may be carrying extensive amounts of gold, as well as barrels of rum and mercury.

But before the explorers can examine the wreckage and possibly display it for the public, they must overcome numerous obstacles in the River Plate.

Muddy waters, fast currents and tons of rock present a serious challenge for recovering the wreckage, Collado said.

Sunk just offshore off Colonia del Sacramento, the Lord Clive was covered with tons of rocky material that crews must remove to bring the ship to land.

Recovery efforts for the 50m six-storey-high ship should begin in August.