A proposed plan to redevelop waterfront areas of Montreal's Old Port would breathe new life into the rusting steel and concrete hulk known as Silo No. 5.

Both revered and maligned, the abandoned grain silo — parts of which date to the early 1900s — dominates the western sector of the port known as Pointe-du-Moulin.

A redevelopment plan designed by architects Daoust Lestage and unveiled Monday would see the old silo crowned with an enclosed glass viewing deck where visitors could take in panoramic views of Montreal's skyline, the St. Lawrence River and the Montérégie region to the south.

A pedestrian bridge would connect the silo to McGill Street and a glass elevator would take visitors to the viewing deck.

Last vestiges of Montreal's '20th-century harbour panorama'

Silo No. 5, and the grain conveyors that connect to it, remain iconic symbols of Montreal's industrial past and are the last vestiges of Montreal's "20th-century harbour panorama," according to the organization Héritage Montréal.

A plan to develop the conveyors into a partial promenade would provide visitors with a closer look at the industrial site and the Lachine Canal below.

Residences, shops, offices, hotels and even a sports centre would round out the Pointe-du-Moulin redevelopment.

An aerial view showing the Old Port and Silo No. 5 and Pointe-du-Moulin. (Canada Lands Company) Héritage Montréal spokesperson Dinu Bumbaru told CBC that the plans for the Pointe-du-Moulin site are "very positive" and would realize a long-sought objective for his organization.

"For 20 years, Héritage Montréal has been asking that we simply stop doing crazy, wild design projects and we just provide an elevator to give people access to the roof and the upper machinery of the silo," he said.

"It will be of great public benefit — the view from there is absolutely remarkable."

The proposal would involve the demolition of the more dilapidated parts of Silo No. 5, including a bank of concrete silos next to the railway bridge.

Delicate balance required

Bumbaru said the loss of those structures is less of a concern than what will replace them, which could include a towering hotel and office building.

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That building would rise between Silo No. 5 and the flour mill topped by the iconic Farine Five Roses sign.

"It would have to be extremely delicate in terms of design," Bumbaru said.

"Farine Five Roses is now acknowledged as one of Montreal's civic icons, its fun icons — is it going to be crushed and diminished by a tower? This is the entrance to Montreal from the Champlain Bridge and it needs to be very delicately worked out."

Stepped plazas, pedestrian bridges

Overall, the $175-million revitalization "master plan" for the Old Port proposes a six-kilometre looped circuit along the waterfront.

"The Old Port esplanade and its waterfront promenade will be completely reconfigured to create a large, linear public space linking Old Montreal, the piers and the waterfront," the plan says.

Once approved, construction could begin in 2019 and it would be built in phases over the next 10 to 15 years.

The proposed plaza at Jacques-Cartier Basin would bring visitors closer to the water, a key element of the Old Port's proposed master plan. (Old Port of Montreal) Other aspects of the redevelopment include:

Stepped plazas down to the water at the Jacques-Cartier and Clock Tower basins.

New pedestrian bridges across the water.

The lowering of the waterfront promenade between St-Pierre and McGill streets under the railway tracks.

A dedicated bike path along de la Commune Street.

A public consultation on the proposed redevelopment plan was held Monday evening at the Montreal Science Centre.

The public can also fill out a survey online until July 12.