William John Slocombe – Mercantile Marine - S.S. Dartmoor

Master William John Slocombe – Mercantile Marine, S.S. Dartmoor

Early Life and Family Background

Birth and Parentage

William John Slocombe was born in 1861 in Swansea, the son of William Slocomb and Agnes Gray Hopgood, who were married in 1856 at Bideford, Devon. The Slocombe family moved between South Wales and Pembrokeshire during William’s early years.

1871 Census

The 1871 Census records the family living on High Street, Fishguard, Pembrokeshire. William’s father, William Slocomb, aged 32, was a Confectioner and Baker, while his mother Agnes, aged 33, managed the household. Their children at home were Thomas Henry (12), William John (10), Frederick Edward Gray (8), Minnie Agnes (6), Sidney (3), and George Arthur, just one month old. This census provides the earliest glimpse of William’s childhood in a busy coastal community.

Early Maritime Career

Apprentices Indentured in the Merchant Navy

Records of Apprentices Indentured in the Merchant Navy show that William began his seafaring career in 1875, beginning a four-year apprenticeship—typical for boys seeking advancement in the Merchant Service.

By 1890, while living in Fishguard, he was awarded a certificate qualifying him as First Mate, marking the first major step toward becoming a ship’s master.

Marriage and Later Life

William John Slocombe and Dinah Howells
marriage certificate
parish church of Llanfair Nant-y-gof, Pembrokeshire

William married twice. His first marriage took place in July 1889 at the parish church of Llanfair Nant-y-gof, Pembrokeshire, when he wed Dinah Howells. Sadly, Dinah died in 1899.

William John Slocombe and Margaret Houghton
marriage certificate 
St. Peter's Church, Liverpool

He remarried in March 1901, at St. Peter’s Church, Liverpool, to Margaret Houghton.

 

1901 Census

The 1901 Census records the newly married couple back in Fishguard, living once again on High Street. William, aged 40, was working as a Mariner, and Margaret, age 23, was from Lancashire. Also present was their young daughter, Margaret F., aged 5.

Service at Sea – Master of the S.S. Dartmoor

By the time of the First World War, William had risen through the ranks to become Master of the S.S. Dartmoor, responsible for the ship, her cargo, and the safety of her crew. Masters often had decades of maritime experience, and William’s long seafaring career had prepared him for command during one of the most dangerous periods in merchant shipping history.

The S.S. Dartmoor

The S.S. Dartmoor was a British steam cargo vessel employed in coastal and near-continental trade during the First World War. Like most merchant steamers of the era, she carried essential raw materials and supplies, powering Britain’s war effort at a time when U-boat attacks were at their height.

Operating through heavily patrolled and dangerous waters, the Dartmoor faced continuous risk from German submarines. On 17^th May 1917, while on passage, the vessel was torpedoed and sunk by the German submarine UC-50. The attack resulted in heavy loss of life, including her Master, William John Slocombe.

German Submarine UC-50

UC-50 was a Type UC II minelaying submarine of the Imperial German Navy. Commissioned in 1916, she was designed for both torpedo attacks and mine warfare. Submarines of this class typically carried: 6 mine tubes; 3 torpedo tubes, and an 8.8cm deck gun

UC-50 operated primarily in the North Sea and English Channel, laying mines and ambushing merchant vessels along Britain’s vulnerable shipping lanes. Her sinking of the S.S. Dartmoor in May 1917 was part of Germany’s intensified campaign to sever Britain’s maritime supply routes.

UC-50 herself was later lost in early 1918, likely to British mines—an ironic end for a vessel designed to deploy them.

Commemoration

S.S. Dartmoor
Tower Hill Memorial, London
credit - Benjidog Historical Research Resources:
The Merchant Navy Memorial 

S.S. Dartmoor
Tower Hill Memorial, London
credit - Benjidog Historical Research Resources:
The Merchant Navy Memorial 

As William John Slocombe has no known grave but the sea, his name is commemorated on the Tower Hill Memorial in London. The memorial honours merchant seafarers who died during both World Wars and whose final resting place is unknown. William’s inclusion ensures that his service and sacrifice—as Master of the Dartmoor—are preserved among the nation’s wartime maritime history.

Legacy

The life and loss of William John Slocombe reflect the profound responsibility borne by merchant shipmasters during the First World War. With decades of experience behind him, William commanded his vessel during a period when merchant ships sailed unescorted through waters patrolled by submarines and mined without warning. His death marks the loss of a skilled and dedicated seaman whose career spanned apprenticeship, certification as First Mate, and ultimately the command of a British merchant steamer.

William’s story is emblematic of the dangers faced by the Mercantile Marine during the war. The men who continued to sail—often without weaponry or protection—played a vital role in sustaining Britain. Their resilience and courage remain an essential part of the nation’s maritime heritage, and William John Slocombe stands among those who made the ultimate sacrifice.