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 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.
In the mid-19th century, lightships began to be 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 old bell on the deck 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. Prior to this, 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. The morning shift was devoted to maintenance work on board. The watch took up the rest of the day, just as it did on other ships. Someone in the crew had to be on watch around the clock. This system meant that there was ample spare time, which was often spent on hobbies such as woodworking.
Length 31 m
Width 6.85 m
Draught 3.1 m
Range of beacon: approx. 11 nautical miles