The fundraiser is to restore the hull and paddles of the last ship of its type to be built in Britain and the largest built for inland waterways, which will be 70 years old next year.
The Glasgow-built vessel has been a static attraction at Balloch pier at the south end of the loch for the last 16 years after being rescued from dereliction following the end of her sailing days in 1981, having carried more than 3 million passengers.
The Loch Lomond Steamship Company, which looks after the Maid, said a further fundraising campaign would be required to complete work necessary for the steamer to sail again.
Activities coordinator Charli Summers said the £25,000 to be raised via the Crowdfunder website which goes live on Friday would be matched by £15,000 pledged by a benefactor.
Donors will be given exclusive access to a new online virtual tour of the ship.
The long-running efforts to restore the Maid have had their ups and downs, with an attempt to haul the 430-tonne ship out of the loch failing two years ago when the slipway carriage she was sitting on was damaged and she slipped back into the water.
A second attempt was completed successfully last July.
Ms Summers said: "We are restoring the hull and paddles first of all and hope to have this completed by spring next year.
"This repair is the most significant development in the ship’s recent history and one of the most challenging parts of the restoration process.
"If we can do this, returning her to her former glory for sailing will take more time and funding, but that is the aspiration of the company.”
Ms Summers said the fully-repaired hull would ensure another 50-60 years of life for the vessel.
She said: “We are hopeful that this will be a platform for starting the fundraising process to get her to sailing standards.”
The latest appeal is to fund materials and equipment such as new paddle floats, bearings and bushes, which will be installed by volunteers to keep costs down.
Ms Summers said a “Jenny Nettles” structure, which maximises the paddles’ efficiency, would also be overhauled because the one on the port (left) side has become misaligned and required significant refurbishment.
Other work will include painting the interior of the paddle boxes, replacement of the spring beams and addition of ending/paddle turning gear.
Jim Mitchell, the company’s industrial heritage director, said: “These funds will allow us to take the paddles to ‘as-new’ condition.
“The plan is for the ship to be returned to the loch with all underwater work completed.
"This, along with the hull work, will be a major leap forward towards the Maid sailing once more.
"With public support, the charity hopes to safely steer the Maid to a new phase of her life, relaunching her as a fully operational paddle steamer on Loch Lomond.”
The vessel, which began her 28-year sailing life in 1953, was licensed to carry 1,000 passengers – the largest on Loch Lomond – with members of the Royal Family among the daytrippers carried.