German G7e torpedo

Both U-boat attacks at Bell Island were made using G7e/T2 torpedoes. These weapons were 7.2 metres long and 53.3 centimetres in diameter. They weighed 1603 kilograms, which included a warhead of 280 kilograms. They had a speed of 30 knots (56 kilometres per hour) and a range of 5 kilometres. They were powered by an electric motor and batteries, which had to be recharged every few days.

The German U-boats experienced chronic problems with the torpedoes’ detonators (which sometimes failed to explode) and the depth-control mechanism (the torpedoes occasionally ran deeper than intended and passed under their target). For example, another U-boat (U-69) attacked SS Rose Castle on October 20, 1942 when the ship was sailing from Sydney, Nova Scotia to Bell Island. The torpedo fired by U-69 hit Rose Castle in the bow but failed to explode, because of a faulty detonator. However, the crew of Rose Castle were not as lucky on November 2 when they were attacked by U-518 and sunk.