The lightship Finngrundet was built in Gävle in 1903. She lay at anchor at the Finngrund banks in the southern Bothninan Sea during the ice free part of the year.
In the 1960s lightships beganto be replaced by fixed, fully automatic, unmanned lighthouse towers ("cassion" lighthouses). The Finngrundet was decommissined in 1969 and has been a museum ship since 1970.
In the mid-19th century, lightships began to be deployed to warn seafarers of shallow banks out at sea. The first lightship came to Finngrundet in 1859. In accordance with international regulations, lightships were painted red and had their names in large white letters along the sides.
The first light on present lightship Finngrundet consisted of paraffin lamps and mirrors. After conversion in 1927, an AGA beacon was installed. At the same time, the old bell on the deck was supplemented by more advanced fog-signal - "nautophone" and underwater signals. during the next conversion, in 1940, the AGA beacon was electrified and rhe Finngrundet also equipped with a radio beacon.
The acquired a radio during the 1927 conversion. This greatly improved conditions for those who worked on the lightship: it enabled them to maintain contact both with other ships and with land. Formerly, the only contact with land had been the seam pilot-vessel that came once a fortnight with food, mail, fuel and other necessities.
On board the Finngrundet was a crew of eight. their main task was to ensure that the light was in working order. Their morning were devoted to maintenance work on board. the watch took up the rest of the day, just as it did on other ships. Someone always had to be on duty - even at night. This system meant that the crew had ample leisure, wich they spent in such pastimed as woodworking.
Length 31 m
Width 6.85 m
Draught 3.1 m
Range of beacon: approx. 11 nautical miles