Relatives of William Finnigan - the first person from Luddendenfoot to lose his life during the First World War - will gather together on Sunday to commemorate him.
William lived on Ellen Holme Royd in Luddendenfoot, with his wife and three children, and was one of 1,450 men killed when three British war ships were torpedoed by a German U-Boat off the coast of the Hook of Holland on September 22, 1914.
William is remembered on the Cenotaph in Holmes Park.
His great grandson Paul Rawlinson, 40, who lives in Rishworth, said: “It was surprising to find so much information on him just by chance, looking through my mum and dad’s belongings.
“But it’s led to a great response from our family since I shared the story, so much so that there’ll be 38 of us commemorating him on Sunday at a service in Luddenden village, and then going onto the Luddendenfoot service at 2pm.
“Some family members are coming as far as Lancashire and Darlington.
“He’d left the navy but signed up to serve again to do his duty.
“There was a loss of 1,450 men between the three ships, all in the space of about 15, 20 minutes.
“You hear a lot about land-based fighting, yet there was a great loss of life at sea as well.”