From the drawing board to the sea: how and where was Titanic built?

Ruling the oceans

White Star Line was founded in 1869 by English shipowner Thomas Henry Ismay. Initially a cargo haulier, the company soon became one of the most prestigious in the transatlantic passenger trade and, from 1908, began work on three liners: RMS Olympic, RMS Titanic and RMS Gigantic, later renamed Britannic. The trio of ships, which comprised White Star Line's Olympic class, were intended to give the company an advantage over its rivals and were noted for their comfort, luxury and reliability rather than speed. Belfast shipbuilders Harland and Wolff undertook most of the design work for Titanic.

The team was spearheaded by naval architect Thomas Andrews, aided by deputy naval architect Edward Wilding and chief draughtsman Alexander Carlisle. Andrews had taken over the role of chief architect from Carlisle, who had officially retired in 1910, though he continued to work on the project as a consultant. It was Carlisle who was responsible for Titanic's graceful lines, as well as a – rejected – design to enable Titanic to carry double the number of lifeboats.

Lord Pirrie, who was a director of both Harland and Wolff and White Star Line, was in charge of the whole project. In July 1908, the plans for Titanic were formally approved by Joseph Bruce Ismay, White Star Line's chairman and the son of founder Thomas Henry Ismay. Olympic and Titanic were constructed alongside each other, with work beginning on Olympic in December 1908 and on Titanic the following March.

A mammoth task

Harland and Wolff was considered one of Britain's most prestigious ship builders. But despite boasting the largest shipyard in the world, the firm didn't initially have facilities big enough to build these two mammoth ships, so three slipways were converted into two larger slipways to accommodate the huge vessels. A steel gantry was added, as were cranes and electric lifts. The usual workforce of 6,000 was more than doubled for the construction of both Titanic and Olympic.

It took 26 months for Titanic to be built. First to be constructed was its keel – the backbone and very bottom of the ship. The hull, the watertight steel body, was then built around it. Four 20-metre funnels towered above the vessel and ensured that it dwarfed any other ship. At 269 metres long, Titanic was the largest man-made moving object in the world. Expectations were certainly riding high.

Harland and Wolff was one of Belfast's largest employers. Many of the shipyard workers lived with their families in the streets around the docks. Working in a shipyard was tough and dangerous, though, and there were 246 injuries recorded while Titanic was being built – including severed limbs, falls from the ship, or legs crushed under steel. There were also eight fatalities during construction, and one worker died on the day of the ship's launch when a wooden support fell on him.

When was Titanic launched?

At just after midday on 31 May 1911, Titanic was launched in Belfast in front of a crowd of around 100,000 people. Those lucky enough to have tickets watched from the slipway, with many more standing on the riverbanks as the ship slid into the River Lagan. Titanic was then towed to its fitting-out basin further down the river at Thompson dock, the specially built largest dry dock in the world at that time, where the ship's machinery and interiors were fitted.

Titanic was powered by two nine-metre-tall steam engines, which drove the ship's three propellers: two directly and one via a turbine. The ship's 29 boilers were fed by 159 furnaces, which needed 660 tonnes of coal each day. This allowed Titanic to reach a maximum speed of 24 knots (28mph).

Those wealthy enough to travel first class were surrounded by luxury and comfort. No expense was spared, and everything was specially made, from the gilt light fittings to the oak staircases.

Second-class accommodation and facilities rivalled that of first class on board Titanic's rival ships. Even for third-class passengers, the standards would have been better than many of them were used to. The ship boasted 10 decks – eight of which passengers could use. Only the bottom two decks were out of bounds: these were the orlop deck, where cargo was stored, and the tank top, the bowels of the ship and the deck upon which the engines and boiler rooms stood.

Why did people think the Titanic was 'unsinkable'?

White Star Line marketed both Olympic and Titanic as "practicably unsinkable" – and stated as much in a 1910 publicity brochure. Titanic's hull boasted 16 special watertight compartments, which could be sealed off in case of emergency and prevent water in damaged sections from flooding the rest of the ship. The ship could remain afloat if no more than four of its forward compartments became flooded – but when the collision with the iceberg occurred, the impact caused six compartments to become open to the sea. Many of the bulkheads (walls between the compartments) had watertight doors, which closed automatically in the event of emergency. Moreover, though the bulkheads extended above the waterline, they were not capped at the top – in other words, water could (and did) spill over the top into neighbouring compartments.

• Read more | 8 stories of passengers who sailed on Titanic

On 3 February 1912, Titanic moved to the dry dock, where its huge propellers were added. Following a final coat of paint, Titanic was complete. It could hold up to 3,547 passengers and crew and, when full, weighed more than 52,000 tonnes. A number of sea trials were carried out to ensure that the engines were in full working order and to see how the ship performed under different speeds, with a practice emergency stop proving it could be brought to a halt from a speed of 20 knots (23mph) in just over half a mile.

From Belfast, the ship made for Southampton to prepare for its maiden voyage. Titanic's first journey was originally scheduled for 20 March 1912, but was delayed; in September 1911, Olympic had been involved in a collision with HMS Hawke, which had diverted manpower and resources away from Titanic's construction for Olympic's repairs. Who knows what may have happened if Titanic had set off on its original March sailing date, before the ice region had extended so far south?

On 10 April, after a near-miss with City of New York, Titanic was finally ready to begin its journey to New York. Crowds lined Southampton's dock to wave goodbye to friends and family and catch a glimpse of the magnificent ship. Titanic sailed to Cherbourg in France and then Queenstown (now Cobh) in Ireland to pick up more passengers, many of whom hoped to start a new life in America. On 11 April, Titanic left Europe behind and sailed into the Atlantic.

• Read next | When did Titanic sink & how long did it take?

This article first appeared in the July 2021 issue of BBC History Revealed