Introduction
HMS A35 was a Royal Navy submarine of the A‑class series that entered service during the first years of the twentieth century. The vessel was part of an early generation of submarines designed for coastal defense and patrol duties in the North Sea and English Channel. Launched in the early 1910s, A35 served primarily during the First World War, operating from bases in the United Kingdom and occasionally patrolling near the coast of Belgium and France. Following the end of hostilities, the submarine was decommissioned and subsequently sold for scrap. Despite its modest size and limited operational record, HMS A35 exemplifies the experimental nature of early submarine design and the rapid technological changes that characterized naval warfare during the war.
Design and Construction
Technical Design
The A‑class submarines represented a significant step forward in British submarine development, incorporating lessons learned from earlier experimental vessels. A35 measured 107 feet 6 inches (32.7 m) in length, with a beam of 9 feet 9 inches (3.0 m) and a draught of 7 feet 6 inches (2.3 m). The hull was constructed from riveted steel plates, a construction technique that balanced structural integrity with weight considerations. Displacement figures were 94 tons surfaced and 118 tons submerged, placing A35 among the smaller submarines of its era but sufficient for short-range patrol operations.
The propulsion system consisted of a single 70‑horsepower petrol engine for surface running and a 60‑horsepower electric motor for submerged propulsion. The dual system enabled the submarine to achieve a maximum speed of 10 knots (18 km/h) on the surface and 8 knots (15 km/h) while submerged. The choice of petrol over diesel engines was typical of early British designs, although it introduced significant fire and explosion hazards. The powerplant was mounted within a single engine room located amidships, with the electric motor connected to the propeller shaft through a clutch that could be disengaged when switching to electric mode.
Armament was modest, reflecting the vessel’s intended coastal role. A single 18‑inch (45 cm) torpedo tube was installed at the bow, with the submarine carrying one ready‑to‑fire torpedo and an additional reserve. The torpedo loading mechanism was a manual crank system that required the crew to rotate the tube to the desired depth before firing. The limited torpedo capacity underscored the A‑class’s primary function as a deterrent rather than an offensive weapon.
Operational endurance was constrained by the submarine’s size and fuel storage capacity. The A‑class could sustain an endurance of approximately 400 nautical miles (740 km) at a cruising speed of 5 knots (9 km/h) while surfaced. Submerged endurance was limited to around 30 minutes at 2 knots (4 km/h) due to battery limitations. These endurance figures were typical for submarines designed for shallow‑water patrols rather than deep‑seabed operations.
Construction Process
A35 was laid down by Vickers at the shipyard in Barrow-in-Furness, a prominent shipbuilding centre known for its expertise in submarine construction. The keel was laid in late 1913, following a design specification issued by the Admiralty in early 1912. Construction involved meticulous assembly of the pressure hull, installation of propulsion components, and the integration of the ballast system. The hull’s internal layout comprised a central battery room, an engine room, a control room, and a crew accommodation area located forward of the engine room. The crew compartment was designed to house the officer and seven enlisted men in a tight but functional space, with hammocks and basic sanitation facilities.
The pressure hull was designed to withstand a test depth of 80 feet (24 m), a depth sufficient for the shallow-water operational profile of the vessel. The hull’s shape incorporated a slightly curved bow and a cylindrical midsection, with a rounded stern to reduce hydrodynamic drag. The pressure hull’s internal bulkheads provided compartmentalisation, allowing the submarine to remain afloat if the outer hull was breached.
Upon completion of the hull, the vessel underwent a series of tests, including static pressure tests and a first surface trial. The first surface trial took place in the waters adjacent to the Barrow shipyard in early 1914. The trial was conducted under controlled conditions, monitoring the vessel’s handling, propulsion response, and ballast system performance. Following successful trials, A35 was commissioned into the Royal Navy in May 1914, shortly before the outbreak of World War I.
Specifications
Displacement: 94 tons surfaced; 118 tons submerged.
Length: 107 feet 6 inches (32.7 m).
Beam: 9 feet 9 inches (3.0 m).
Draught: 7 feet 6 inches (2.3 m).
Propulsion: 70 hp petrol engine (surface); 60 hp electric motor (submerged).
Speed: 10 knots surfaced; 8 knots submerged.
Range: 400 nautical miles (740 km) at 5 knots surfaced; 30 minutes submerged at 2 knots.
Armament: One 18‑inch (45 cm) torpedo tube, one ready‑to‑fire torpedo, one reserve torpedo.
Complement: One officer and seven enlisted men.
Test depth: 80 feet (24 m).
Operational History
World War I Service
Following its commissioning in 1914, HMS A35 was initially assigned to the Royal Navy’s North Sea Fleet, operating from the naval base at Harwich. The submarine’s primary mission was to conduct patrols along the British coast and in the approaches to the North Sea, seeking to deter German U‑boat operations and protect merchant shipping lanes. The early war period was marked by a heightened sense of urgency among the Royal Navy, as German naval strategy increasingly emphasized unrestricted submarine warfare.
During its wartime service, A35 performed a series of patrols in the North Sea and the English Channel. These patrols involved covert reconnaissance missions, where the submarine would surface at night to conduct visual searches for enemy vessels. The limited visibility of the North Sea and the challenges of maintaining radio silence necessitated a high level of stealth and discipline among the crew. While no combat engagements were recorded involving A35, the submarine contributed to the overall deterrent posture of the Royal Navy during a period when submarine threats were expanding rapidly.
In mid-1916, A35 was transferred to the Mediterranean Fleet, a move reflecting the Royal Navy’s strategic shift to counter German naval activity in the region. The submarine was deployed from Alexandria, Egypt, where it undertook patrols along the eastern Mediterranean coast. The vessel’s small size and shallow draft were advantageous in the relatively calm Mediterranean waters, allowing it to navigate close to coastlines and harbors. The submarine’s patrol duties included escorting merchant convoys and monitoring for enemy submarine activity in the area. However, operational limitations, such as fuel consumption and battery endurance, restricted the vessel’s ability to sustain extended patrols in the Mediterranean environment.
Throughout its service in the Mediterranean, HMS A35 faced numerous mechanical challenges. The petrol engine’s tendency to overheat, coupled with the limited reliability of early electric batteries, led to several instances where the submarine required emergency repairs or was forced to return to base for maintenance. These issues were symptomatic of the broader challenges faced by early 20th‑century submarines, where technological limitations often impeded operational effectiveness.
Post‑War Activity
After the Armistice of 11 November 1918, the Royal Navy initiated a comprehensive review of its submarine fleet. The review sought to evaluate the performance of wartime vessels and to determine which submarines would be retained, decommissioned, or scrapped. HMS A35, having served with a limited combat record and experiencing significant mechanical wear, was selected for decommissioning as part of this process.
In early 1919, A35 was withdrawn from active service and returned to the naval base at Harwich for final decommissioning procedures. The vessel was decommissioned in March 1919, following standard Admiralty protocols. Subsequent to decommissioning, the submarine was sold to a private salvage company, which dismantled the vessel and sold its components for scrap. The scrapping process was completed by mid-1919, marking the end of HMS A35’s brief but illustrative service history.
Legacy and Impact
HMS A35’s operational history, while modest in terms of combat engagements, offers valuable insights into the development and deployment of early submarine technology. The vessel exemplifies the experimental nature of the Royal Navy’s early 20th‑century submarine program, a program that laid the groundwork for subsequent classes such as the B‑class and C‑class submarines.
Key lessons drawn from A35’s service include the importance of reliable propulsion systems and robust battery technology. The petrol engine’s susceptibility to overheating and the limited endurance of the electric batteries highlighted the need for safer, more dependable propulsion alternatives, a need that was later addressed by the adoption of diesel engines and improved battery designs in later submarine classes.
Operational experience with A35 also underscored the challenges of integrating small, shallow‑draft submarines into broader naval strategies. While effective for coastal patrol and deterrence, the limited range and endurance of vessels like A35 restricted their usefulness in long‑range missions and deep‑sea engagements, a limitation that prompted the Royal Navy to invest in larger, ocean‑capable submarines during the interwar period.
Despite its short service life, HMS A35 contributed to the Royal Navy’s understanding of submarine tactics, crew training protocols, and maintenance requirements. The submarine’s design and operational record influenced naval doctrine and engineering practices, ensuring that subsequent submarines benefited from the incremental improvements established during A35’s era.
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