A 33-foot-long hand-drawn plan of the Titanic that was used in the British Board of Trade’s inquiry into the ship’s sinking in 1912 is going on display in Belfast City Hall over the Easter weekend, from April 23 to April 26. It is privately owned, so this the first time it’s been displayed publicly since the inquiry.

Drawn by White Star Line architects in India ink on a single piece of paper, the plan is a cross-section scaled to 3/8 of an inch to the foot. It shows all of Titantic’s main features, from passenger cabins to cargo holds and boiler rooms. It was created to give the inquiry commissioners a detailed picture of the ship’s construction, and includes copious notes and red and green chalk marks on the hull where witnesses and officials marked where they thought the iceberg had penetrated five of Titanic’s watertight bulkheads.

The 1912 British inquiry into the sinking of Titanic lasted 36 days. It heard the testimony of nearly 100 witnesses, including surviving crew members, White Star Line officials, and maritime experts.

The only surviving passengers interviewed were Sir Cosmo and Lady Duff-Gordon, and White Star Line President J Bruce Ismay: all first-class passengers.

The inquiry was heavily criticised for not speaking to a single passenger from the lower decks of the ship.

After asking more than 25,000 questions of witnesses, the inquiry eventually concluded that: “The loss of the said ship was due to collision with an iceberg, brought about by the excessive speed at which the vessel was being navigated.”

One of the witnesses was Guglielmo Marconi, inventor of the radio and the wireless telegraphy system which Titanic was one of the first ships to use. Another was Ernest Shackleton, Arctic explorer of recent whisky fame, who testified as an expert in navigating icy waters.

Complete transcripts of the Board of Trade’s inquiry have been put on online at the Titanic Inquiry Project website, along with transcripts from the US Senate’s inquiry, and depositions from the lawsuit against the Oceanic Steam Navigation Company, the White Star Line’s parent company. It’s a treasure trove for Titanic buffs, of course, but also for general history nerds like yours truly. You can read Shackleton’s testimony here, and Marconi’s here (my favorite part is where he talks about the newly created S.O.S. standard for distress signals).

The plan will be displayed along with over 250 other items of Titanic and White Star Line memorabilia from specialist White Star Line auctioneers Henry Aldridge and Son. The drawing will then go up for auction on May 31, to coincide with the 100th anniversary of Titanic’s launch on May 31st, 1911.

There will be other exhibits and events held by the Belfast City Council as part of their commemoration of the launch, the “Titanic 100” festival, including lectures, film viewings, tours of the Belfast shipyard where Titanic was built, photographs chronicling the building of Titanic and more.