(Adds survivor's condition)

A catamaran has sunk in shallow water off Valletta waterpolo pitch in Marsamxett after a fierce fire.

Eyewitnesses said the blaze followed an explosion at about 5.10 p.m. as the yacht was sailing out. It quickly spread across the vessel as it drifted towards Valletta.

The sole crewman - Brian Felder, 58, jumped into the sea and was rescued by another catamaran. He was rushed to Mater Dei Hospital suffering burn wounds. The police said this evening his condition was life threatening.

Assistance was given by the AFM launch Melita and the Civil Protection Department rescue vessel Garibaldi and a fire engine stood by on shore.

The fire produced a thick plume of smoke visible from a wide area around Marsamxett.

The wreck was almost totally submerged within an hour.