Thompson Graving Dock

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Thompson Graving Dock is a large dry dock in Belfast, Northern Ireland, best known as the place where the Titanic was finished before she began her voyage. It was built to let Belfast’s shipyards finish bigger ocean liners without sending them elsewhere.

History and construction
- Construction began in October 1903 next to Alexandra Dock, and the dock opened on 1 April 1911.
- It cost about 350,000 pounds.
- The project was led by the Belfast Harbour Commissioners to support the city’s growing shipbuilding and repair industry.

What it is and how it works
- Thompson Graving Dock is a big rectangular pit dug into the ground, with granite side walls and a thick floor. The walls are very sturdy and the floor is solid to support big ships.
- A large caisson gate closes and opens the dock. This is a floating steel box that can be flooded to sit in the dock opening and then pumped dry to let ships in.
- The pumping station, shared with the nearby Alexandra Dock, had about 3,000 horsepower of pumps and could empty the dock in about 119 minutes.
- A land-side capstan was used to pull ships into the dock by hand. Inside, ships rested on keel blocks along the center and bilge blocks on the sides, with shores and blocks that could be moved to keep the ship steady.

Dimensions and layout
- Normal usable length: about 850 feet 6 inches (259 meters). With the gate placed differently, it could reach about 886 feet 6 inches (270 meters). The coping length was about 900 feet (274 meters).
- Width: 100 feet (30.5 meters) at the floor, 96 feet (29.3 meters) at the entrance, and 128 feet (39 meters) across the top.
- Depth: about 42 feet 6 inches (13.0 meters) from floor to coping.
- The sill depth below water varied with the tide.

Notable ships and work done
- The first ship serviced was the Olympic. Olympic entered the dock for fitting out and trials in 1911, and Titanic also spent time there for propeller fitting, interior furnishing, and anti-fouling paint.
- Olympic had a couple of accidents while in the dock, which required urgent repairs.

Later history
- By the 1960s Thompson Dock had become too small for the era’s largest ships. Belfast Dry Dock (a larger reinforced concrete facility) was built nearby between 1965 and 1968.
- As the shipbuilding industry declined, Thompson Graving Dock fell out of routine use and was closed in 2002.
- It has since been repurposed as a tourist attraction. The pump house building now hosts a whiskey distillery. The Alexandra Graving Dock beside it houses the museum ship HMS Caroline.