CHENNAI: The lighthouse at the Marina that has, in various incarnations, safely guided mariners to port for years, will soon be open to the public again.

More than two decades have passed since the authorities closed it to the public due to security concerns and to protect the structure after the assassination of Rajiv Gandhi in May 1991.

The directorate of lighthouses and lightships has decided to open the 45.72-metre-high structure to the public from August. Visitors will be able to take the elevator within the tower till the 9th floor of the 10-storey structure. Sea-facing balconies on two sides of the tower, painted in distinctive red and white bands, will offer an unrivalled view of the Bay of Bengal.

Former Union shipping minister G S Dhillon opened the new lighthouse off Kamarajar Salai in January 1977, but the city has had a lighthouse at least since 1796.

Madras Lighthouse is the only one in the country within city limits, but it has been off limits for the public for more than 22 years.

The authorities closed it to the public following the assassination of Rajiv Gandhi in Sriperumbudur on May 21, 1991. “It is the only lighthouse in the country in which the public is not permitted,” directorate-general of lighthouses and lightships regional director T Ramadoss told TOI. “We have received the go-ahead to reopen it to visitors from August.”

Visitors will be permitted to take the stairs or the elevator till the 9th floor of the 10-story tower, where balconies on two sides of the three-sided structure provide spectacular views of the Bay of Bengal. But the authorities fear the balconies may not be safe for the public now and have decided to raise their railings by four feet.

The directorate-general of lighthouses and lightships is also considering a revamp of the 27-year-old elevator, possibly with transparent walls so as to give visitors a glimpse of the town through portals in the lighthouse.

The lighthouse has a fascinating history, Ramadoss said. “While there must have been some system of lighting to guide East India Company vessels into Madras port during 17th and 18 th centuries, there are no records available to confirm this or show exactly what it was,” he said.

Chennai’s first conventional lighthouse was powered by an oil wick lamp. It was built on the terrace of the officer’s mess and exchange building, within what is now known as Fort Museum at Fort St George, in 1796, when the sea came up close to the walls of the fort, said Ramadoss.

The British installed a new flashing light, consisting of Argand oil lamps and reflectors, in 1844. Fifty years later, the lighthouse equipment with lantern was shifted onto the dome of the high court building.

The new lighthouse was opened in January 1977. “It uses electrical equipment manufactured by BBT, Paris,” Lighthouse keeper S Palaniswamy said.

The light generated by three 150V metal halide lamps, enhanced by a four-panel convex lens, can be seen from up to 30 nautical miles (34.5 miles /55.6km ) out at sea.

The lighthouse also has radio beacons on the ninth floor to aide navigation of vessels. “The national automatic identification system and coastal static sensors installed by coast guard atop the lighthouse also monitor movement of ships extensively,” said DLL deputy director K Shakthi.