Overview
SM U‑6, also designated U‑VI, was a submarine of the Austro‑Hungarian Navy built during the early 20th century. It belonged to the U‑5 class—a group of three boats constructed by Whitehead & Co. of Fiume (now Rijeka, Croatia) as part of a naval programme to evaluate foreign submarine designs. The vessel entered service shortly before World War I and saw limited combat action before being scuttled in May 1916 after becoming entangled in an anti‑submarine net of the Otranto Barrage.
Design and construction
- Builder: Whitehead & Co., Fiume
- Ordered: 1906; laid down 21 February 1908; launched 12 June 1909; commissioned 1 July 1910.
- Class: U‑5‑class submarine (the second of three boats in the class).
The design was derived from a licence for an American John Philip Holland model, incorporating a single hull with a teardrop‑shaped body. Dimensions were 105 ft 4 in (32.11 m) length, 13 ft 9 in (4.19 m) beam and 12 ft 10 in (3.91 m) draft. Displacement was 240 t surfaced and 273 t submerged.
Propulsion consisted of two six‑cylinder gasoline engines delivering a combined 500 bhp for surface running, complemented by twin electric motors producing 230 shp when submerged. The submarine could achieve 10.75 knots (19.9 km/h) on the surface and 8.5 knots (15.7 km/h) underwater. Range was approximately 800 nmi at 8.5 knots surfaced and 48 nmi at 6 knots submerged.
Armament comprised two 45‑cm bow torpedo tubes (both forward) with a capacity for four torpedoes, and later the addition of a single 3.7 cm/23 quick‑firing deck gun in December 1915. The crew complement was 19 officers and men.
Ventilation on board was poor; gasoline engine exhaust often caused crew intoxication, a noted drawback of early submarine designs.
Service history
Initially employed as a training vessel, U‑6 performed frequent short cruises, sometimes up to ten per month. At the outbreak of World War I it was one of only four operational Austro‑Hungarian submarines and operated from the naval base at Cattaro (now Kotor, Montenegro).
During the war, its combat record includes:
- An unsuccessful attack on an Italian destroyer (23 February 1916).
- The sinking of the French destroyer Renaudin on 18 March 1916 off Durazzo, resulting in the loss of 47 of the ship’s crew.
On 13 May 1916, while attempting to pass beneath drifters enforcing the Otranto Barrage, U‑6 became caught in an anti‑submarine net. After surfacing and being subjected to gunfire from nearby drifters, the commander ordered the destruction of confidential material and scuttled the vessel. All three officers and seventeen crew members were rescued and taken as prisoners of war by Italian forces.
Fate
U‑6 was deliberately sunk (scuttled) on 13 May 1916 after entanglement in anti‑submarine netting. The crew survived, but the submarine was lost to the Austro‑Hungarian fleet.
Specifications (summary)
| Parameter | Value |
|---|---|
| Class & type | U‑5‑class submarine |
| Displacement | 240 t surfaced / 273 t submerged |
| Length | 105 ft 4 in (32.11 m) |
| Beam | 13 ft 9 in (4.19 m) |
| Draft | 12 ft 10 in (3.91 m) |
| Propulsion | 2 × gasoline engines (500 bhp total); 2 × electric motors (230 shp total) |
| Speed | 10.75 knots surfaced; 8.5 knots submerged |
| Range | 800 nmi at 8.5 knots surfaced; 48 nmi at 6 knots submerged |
| Complement | 19 personnel |
| Armament | 2 × 45 cm torpedo tubes (4 torpedoes); later 1 × 3.7 cm deck gun |
Legacy
SM U‑6 exemplifies early Austro‑Hungarian submarine development and the challenges of integrating foreign designs into a nascent naval force. Its brief combat service, culminating in the loss during anti‑submarine operations, reflects the hazardous nature of undersea warfare in the First World War.