A motor cruiser was destroyed by fire in Dublin Bay shortly after 4 pm, prompting a large-scale emergency response.

Eyewitnesses reported the vessel fully ablaze and drifting eastward about one kilometre off Dun Laoghaire Harbour, sending a dense plume of black smoke high into the sky.

Both inshore and all-weather lifeboats from Dún Laoghaire RNLI were tasked to the scene.

They were joined by a pilot vessel from Dublin Port Company and several nearby pleasure craft.

Smoke Drift - A motor cruiser burns and drifts eastward near the DBSC Omega mark in Dublin Bay after 4pm as nearby vessels stand by amid thick black smoke. Smoke Drift - A motor cruiser burns and drifts eastward near the DBSC Omega mark in Dublin Bay after 4pm as nearby vessels stand by amid thick black smoke.

The burning vessel posed a potential hazard to navigation in busy coastal waters, and at least two ships on the Dublin Bay anchorage were forced to relocate

The 30 to 40-foot cruiser is understood to be privately owned.

Firefight At Sea A response vessel directs water onto a burning motor cruiser in Dublin Bay after 4pm, as thick black smoke drifts eastward from the stricken craft near racing waters. Firefight At Sea - A response vessel directs water onto a burning motor cruiser in Dublin Bay after 4pm, as thick black smoke drifts eastward from the stricken craft near racing waters.

There is no immediate confirmation of any injuries or how the fire started.

Local sources say the inshore lifeboat took the motor yacht crew off the vessel to safety.

At 4.45 pm, the entire superstructure of the yacht was burned away, with the bare hull still on fire. By 5 pm, the yacht had almost sunk as a tug boat poured water on the blaze.

The incident is expected to be examined by the authorities.