A Coast Guard vessel sank while on patrol duty off the coast of Jafrabad town in Amreli district in Gujarat, about 350 km from Ahmedabad, due to 'unprecedented storm-like weather conditions', police said on Tuesday.

However, all nine crew members of Hariprasad swam to safety after the vessel capsized between Shia bet and Babar Kot near the Gulf of Khambat at around 1600 IST on Monday, police said.

The crew reportedly lost two SLR rifles, one 9mm carbine, two pistols, several rounds of ammunition and a wireless set that they were carrying along on board the vessel.

Amreli police sources said the reason cited in the FIR registered with them was that 'bad weather and storm caused the vessel to capsize and sink' and there was no sign of sabotage.

Efforts to recover the weapons and equipment would be underway once the weather conditions improved, police added.