The Government has awarded €1.5 million towards refurbishing the historic Mariners' church in Dún Laoghaire, Co Dublin.
The early 19th-century church houses the National Maritime Museum, which is run voluntarily by the Maritime Institute of Ireland.
The grant through the Office of Public Works represents the first State funding in 15 years for the building, which is in a very fragile state.
The optic from the Bailey lighthouse in Howth, Co Dublin, and a model of the Great Eastern - the ship that laid the transatlantic cable under the command of Wicklow man Capt Robert Halpin - are among the many maritime artefacts housed in the tiny church overlooking Dún Laoghaire harbour.
It also exhibited the Bantry longboat for many years until it was reclaimed by the National Museum. It is currently being restored in Liverpool.
The museum was originally based on St Michael's Wharf, and moved to the Mariners' church building in 1971.
Maritime historians John de Courcy Ireland and Des Branigan were among the early members of the Maritime Institute who campaigned for State support for the initiative.
Some €300,000 was awarded in 1991, but since then the building has had little finance for maintenance and the museum has survived through the goodwill of institute volunteers.
Michael Prior, the Maritime Institute's president, said he was delighted with the development.
"It is a great tribute to Des Branigan, in particular, who has lobbied over many years."
The building is due to be dedicated, at Mr Branigan's suggestion, to all those Irish mariners who lost their lives during the second World War in their efforts to maintain vital sea links.
"We see our role as primarily educational, and we would like to build on this," Mr Prior said.
Last summer, for instance, the museum worked with Wicklow Vocational Education Committee on an exhibition of the Capt Halpin collection.
Fianna Fáil TD Barry Andrews has also welcomed the grant aid, saying that it would safeguard one of the most important links between the town and its maritime heritage.
"Our local maritime history is something Dún Laoghaire should not only remember, it is something we should be proud of. The granting of the funding underlines the importance of this heritage, not only to our own local area, but to the country as a whole."
