SF Hydro

Hydro at Mæl in 1925
History
Name:	SF Hydro
Operator:	Norsk Transport
Port of registry:	Oslo, Norway
Route:	Tinnsjø railway ferry
Yard number:	374
Launched:	10 December 1914
Out of service:	20 February 1944
Fate:	sunk by SOE (Special Operational Executive) in World War II
General characteristics
Tonnage:	493.60 tonnes
Length:	53 m (174 ft)
Beam:	9.6
Draft:	3.2 m
Installed power:	2x 186 kW steam engines
Speed:	8 knots
Capacity:	120 passengers
Notes:

SF Hydro was a Norwegian steam powered railway ferry that operated in the first half of the 20th century on Lake Tinn in Telemark. It connected with the Rjukan Line and Tinnoset Line, at Mæl and Tinnoset, operating between 1914 and 1944. The combined track and ferry service was primarily used to transport raw materials and fertilizer from Norsk Hydro's factory at Rjukan to the port in Skien. It was the target of a Norwegian operation on 20 February 1944, when resistance fighters sank the ferry in the deepest part of Lake Tinn in order to prevent Nazi Germany from sending heavy water to Germany.

The railway ferries operated a 30-kilometre (19 mi) route connecting the Tinnoset Line and Rjukan Line. Transport included both railway cars, carrying primarily fertilizer, potassium nitrate and ammonia from Norsk Hydro, as well as passengers.

Hydro was the second ship delivered for the service; the initial ship, SF Rjukanfos, had been delivered in 1909 but soon proved too small for the service. Hydro was ordered from Akers Mek. Verksted on 19 July 1913 on a bid of NOK 268,000; in the end the cost was NOK 334,293. It was launched on 10 December 1914, but rebuilt and relaunched on 5 June 1915 as the original configuration used too much coal.