Restoration work is already under way, but far more needs to be carried out to return the ship to its former glory.
The SS Explorer has already been saved from the scrapyard on two occasions.
Now an urgent appeal has been launched to find the £100,000 needed to keep it berthed in Edinburgh.
It has been berthed in Edinburgh since 1998 - attracting nearly half a million people in its first year alone.
The SS Explorer was built in 1955 and was the last complete ship to leave Alexander Hall's shipyard in Aberdeen.
However, she must leave her current berth at Leith in April unless £100,000 can be raised to restore the vessel to her former glory and secure a permanent berth.
"We think she would make a lovely sister attraction to Britannia because she's a similar age and similar size, but the opposite side of the coin - a real working ship," said preservation society chairwoman Elaine Macnab.
First computer
"It's a time capsule, a living history book."
The ship was originally built as a research vessel for the Department of Agriculture and Fisheries' marine laboratory in Aberdeen.
She was the first of her kind to carry a computer - which fully occupied a substantial cabin.
In addition to about 30 cabins and three laboratories, the ship also housed a luxurious officer's saloon complete with a fire place.
The SS Explorer was decommissioned in 1984 and has been moored at Leith for the past four years.
Restoration work is already under way, but far more needs to be carried out to
return the ship to its former glory.
Ms Macnab said the ship had been saved from the scrapyard twice since it was decommissioned.
"We are determined it's not going to be third time lucky," she said.
"I would appreciate any help we can get really. If anybody has got any ideas or would like to help with fundraising, we would be very happy."
The SS Explorer Preservation Society, which has an 80-strong membership drawn from across the UK, is trying to raise awareness of the ship's plight and devise fundraising initiatives.