SF Hydro

Hydro at Mæl in 1925
History
Name	SF Hydro
Operator	Norsk Transport
Port of registry	Oslo, Norway
Route	Tinnsjø railway ferry
Builder	Akers mek. Verksted, Oslo
Cost	NOK 334,293
Yard number	374
Launched	10 December 1914
Out of service	20 February 1944
Fate	Sunk by Special Operations Executive (SOE) in World War II
General characteristics
Tonnage	493.60 tonnes
Length	53 m (174 ft)
Beam	9.6
Draft	3.2 m
Installed power	2 × 186 kW steam engines
Speed	8 knots
Capacity	120 passengers
Notes	[1]

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 to prevent Nazi Germany from receiving heavy water.