SS Imo

Harland & Wolff built the ship in Belfast as yard number 211. She was launched on 1 January 1889 and completed on 16 February. She was designed to carry 1,000 head of live cattle, plus she had berths for 48 passengers. As built, her tonnages were 4,649 GRT and 3,046 NRT.

Her first owner was the Oceanic Steam Navigation Co, which was part of White Star Line. She was registered at Liverpool. Her United Kingdom official number was 93837 and her code letters were LBPW. In May 1895, the West Indies and Pacific Steamship Line acquired the ship and renamed her Tampican. On 31 December 1899 she was transferred with the rest of the company's fleet to Frederick Leyland & Co.

In 1912, HE Moss acquired Tampican, but in the same year, he sold her on to the Southern Pacific Whaling Company, who had her refitted as a whaling factory ship. This changed her tonnages to 5,043 GRT and 3,161 NRT. She was renamed Imo and registered in Christiania (now Oslo), Norway. Her code letters were changed to MJGB.

In 1917, Imo sailed as a charter for the Belgian Relief Commission. Being neutral, Imo had on her side the words "Belgian Relief" to protect her from German and Austro-Hungarian submarines. Imo was sailing in ballast (empty) en route to New York to load relief supplies. She reached Halifax on 3 December for neutral inspection, and spent two days in Bedford Basin awaiting bunkering. She was cleared to leave port on 5 December, but was delayed as her bunker coal did not arrive until late that afternoon. Bunkering was not completed until after the anti-submarine nets had been raised for the night, so she could not weigh anchor until the next morning.

Imo had a crew of 39 men, commanded by Captain Haakon From. With a registered length of 430.7 ft (131.3 m) but a beam of only 45.2 ft (13.8 m), Imo was long and narrow. Because she was in ballast (without cargo), her propeller and rudder were nearly out of the water, making her hard to steer. She was powered by a triple-expansion steam engine with a single 20-foot right-hand propeller, able to make 60 revolutions per minute. Her propeller gave her a "transverse thrust", i.e. while making headway she veered to the left, in reverse she swung to the right. Under these conditions, Imo was at a disadvantage in navigating in tight quarters. "Due to the combined effect of transverse thrust and the length, and depth of SS Imo's hull, and its keel, she was difficult to maneuver".

The guard ship HMCS Acadia signalled Imo clearance to leave Bedford Basin at about 7:30 a.m. on the morning of 6 December, with Pilot William Hayes aboard. Imo entered the Narrows well above the harbour's speed limit, in an attempt to make up for the delay from bunkering. Imo met a US tramp steamer, SS Clara, being piloted up the wrong (western) side of the harbour. The pilots agreed to pass starboard to starboard. Soon afterwards, Imo was forced to head even further towards the Dartmouth shore after passing the tugboat Stella Maris, which was travelling up the harbour to Bedford Basin near mid-channel. …

Imo was refloated 26 April 1918, repaired and returned to service. Renamed Guvernøren ("The Governor") in 1920, she was a whale oil tanker until 30 November 1921, when the man at the helm collapsed drunk after celebratory drinking, leaving nobody at the wheel. The ship ran aground on rocks at Cow Bay two miles off Cape Carysfort about 20 miles from Port Stanley on East Falkland. No crew were lost. Salvage attempts were halted on 3 December and the ship was abandoned to the sea.

In 2005, the Falkland Islands issued a postage stamp showing Guvernøren. The Maritime Museum of the Atlantic in Halifax, Nova Scotia has an exhibit about the ship's role in the Halifax Explosion, which also displays some fittings from Imo including a dog collar from the ship's mascot.

On 6 November 2017, Canada Post issued a stamp commemorating the devastating explosion. Released one month before the blast's centenary, the issue also salutes the resilience of the Haligonians who rebuilt their city from the ashes.

The stamp captures the moments before and after the disaster through elements from the past and present. Local illustrator Mike Little and historical consultant Joel Zemel (who also wrote the descriptive text) recreated the scene based on archived historical materials including witness accounts from the inquiry. Because the ships' plans were not available at the time, three extant photographs of SS Mont-Blanc, and several available images of Imo were used as the main references. An image of the front page of The Halifax Herald the day after the explosion shows the heartbreaking aftermath. The stamp was designed by Larry Burke and Anna Stredulinsky of Burke & Burke in Halifax.