Martin Kull – Mercantile Marine - S.S. Cayo Bonito

Fireman and Trimmer Martin Kull – Mercantile Marine, S.S. Cayo Bonito

Early Life and Family

Among the foreign-born seamen who made Swansea their home and served with the Mercantile Marine during the First World War was Martin Kull, a Russian-born mariner who shared the hardships and dangers faced by merchant sailors of all nations.

Martin was born in 1893, in Cowland, Russia, the son of Jacob Kull. While little is known about his early life, it is likely that, like many young men from northern Europe, he sought opportunity and a steady livelihood in the bustling ports of Britain.

He eventually settled in Swansea, where he married Florence May Richards. The couple lived at 56 Tymawr Street, Port Tennant, a community closely linked with the docks and the life of the sea.

Service and Loss

During the First World War, Martin served in the Mercantile Marine as a Fireman and Trimmer aboard the S.S. Cayo Bonito, a British steam cargo ship. His work below decks — shovelling coal and tending the furnaces — was arduous and dangerous, especially during wartime voyages when ships travelled under blackout and constant threat of attack.

On 11^th October 1917, the Cayo Bonito was torpedoed and sunk by a German submarine in the Gulf of Genoa, off the coast of Italy, while sailing from Swansea to Livorno (Leghorn) with a cargo of patent fuel. The attack came suddenly and without warning. The vessel went down quickly, and Martin Kull was among those who lost their lives.

He was 24 years old. His body was never recovered — his grave, like that of many mariners, is the sea.

The S.S. Cayo Bonito

The S.S. Cayo Bonito was a British steam cargo vessel of 3,427 gross register tons, built in 1901 by J. Readhead & Sons Ltd., South Shields. Owned by the Cayota Steamship Company Ltd. and managed by G. H. Myers & Co., the ship was employed in the coastal and continental trade routes that formed the backbone of Britain’s maritime commerce.

On 11^th October 1917, while on passage from Swansea to Livorno, the Cayo Bonito was torpedoed and sunk by the German submarine SM UC-35 at coordinates 44° 14′ N, 8° 30′ E, approximately 4 nautical miles ENE of Savona. The ship’s loss underscored the far-reaching nature of the U-boat threat — extending even into Mediterranean trade routes that had once been considered relatively safe.

The German Submarine SM UC-35

The SM UC-35 was a Type UC II minelaying submarine of the Imperial German Navy, launched in 1916 and commissioned on 2^nd October 1916. Built by Blohm & Voss of Hamburg, the submarine was part of Germany’s formidable fleet of coastal minelayers and torpedo boats.

• Displacement: 427 tons (surfaced), 509 tons (submerged)
• Length: 50.35 metres (165 ft 2 in)
• Beam: 5.22 metres; Draught: 3.65 metres
• Propulsion: Diesel-electric, two diesel engines and two electric motors
• Speed: 11.8 knots (surfaced), 6.6 knots (submerged)
• Armament: Six mine tubes, three 50 cm torpedo tubes (two bow, one stern), and one 8.8 cm deck gun

Under the command of Kapitänleutnant Herbert Pustkuchen, UC-35 carried out 11 patrols, sinking 47 ships with a total tonnage exceeding 70,000 tons, and damaging another five vessels. The submarine operated mainly in the Mediterranean Sea, targeting Allied shipping routes to Italian ports such as Genoa, Livorno, and Naples.

It was during one of these patrols that UC-35 attacked and sank the S.S. Cayo Bonito on 11^th October 1917, killing Martin Kull and many of his shipmates.

Fate of UC-35: On 16^th May 1918, the submarine was sunk southwest of Sardinia by gunfire from the French naval trawler Ailly. All hands were lost, bringing an end to one of the most destructive U-boats operating in the Mediterranean.

The story of UC-35 demonstrates the relentless efficiency of the German U-boat campaign and the immense danger faced by the merchant seamen who braved mined and torpedo-ridden waters to keep Britain’s supply lines open.

Commemoration

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

Fireman and Trimmer Martin Kull is commemorated on the Tower Hill Memorial, London — the national monument dedicated to the officers and men of the Merchant Navy and Fishing Fleets who gave their lives in both World Wars and who have no known grave but the sea.

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

Legacy

Though born in Russia, Martin Kull made Swansea his home, joining a seafaring community that drew men from across Europe. His service aboard the Cayo Bonito exemplifies the courage and endurance of those who served in the Mercantile Marine, risking their lives to sustain Britain’s lifelines during war.

His name, inscribed on the Tower Hill Memorial, stands as a lasting reminder of the international brotherhood of mariners — and of the heavy price paid by those who kept the world’s ships moving through perilous seas.