The Lightship Finngrundet was built in Gävle in 1903. She lay at anchor at the Finngrundet banks in the southern Bothnian Sea during the ice free part of the year.
From the mid-19th century, lightships were deployed to warn seafarers of shallow banks out at sea. The first lightship was anchored at the Finngrundet banks in 1859. In accordance with international regulations, lightships were painted red and had their names in large white lettering along the sides.
The first light on Finngrundet consisted of paraffin lamps and mirrors. This was replaced by an AGA beacon in 1927. At the same time, the ship's bell was supplemented by more advanced signalling equipment in the form of a nautophone and a submarine bell. In 1940, the AGA beacon was electrified and the ship was also equipped with a radio beacon.
During the 1927 refit, a radio was installed. This greatly improved conditions for the crew as it enabled them to maintain contact both with other ships and with land. Before then, the only regular contact with the outside world had been a pilot boat which arrived once a fortnight to deliver food, mail, fuel and other necessities.
The ship had a crew of eight. Their main task was to ensure that the light was in working order. Life aboard a lightship was characterized by routine tasks, but there was also ample spare time which was often spent fishing or on hobbies such as woodworking.
In the 1960s, lightships were gradually replaced by fixed, fully automatic, unmanned lighthouse towers (caisson lighthouses). Finngrundet was decommissioned in 1969 and has been a museum ship since 1970.
Length 31 m
Width 6.85 m
Draught 3.1 m
Range of beacon: approx. 11 nautical miles