Regarding the “Ship Notes” feature on the Nantucket Lightship LV-112 (Sea History 173, Winter 2020–21, pages 40–41):
There is an enormous bulbous mushroom-shaped thing sticking out of the leading edge of its bow above the waterline.
What is that? From Robert M. Mannino, Jr., President of the US Lightship Museum: That enormous bulbous thing is a US lightship mushroom anchor. What makes this anchor special?
Lightships were “floating lighthouses,” anchored in waters where it was not practical to build a permanent lighthouse.
Just like lighthouses, they were equipped with flashing light beacons, loud foghorns, and radio beacons to help guide ships past dangerous waters.
Between 1820 and 1983, 179 lightships were built in the United States and administered
by the US Lighthouse Service, which merged with the US Coast Guard in 1939.
The last US lightship was built by the US Coast Guard in 1952. Where were US lightships stationed?
Lightships were stationed along the East and West coasts, the Gulf of Mexico and the Great Lakes.
Anchored several miles off the coast, they often could not be seen from the mainland.
In 1909, during the height of the United States Lightship Service, there were 56 lightships on station.
Each lightship had an average crew size of 10 to 12 sailors, who lived on board for weeks at a time.
Regardless of weather conditions, the duty of the crew was to keep the lightship operational and anchored on station, even during violent hurricanes and ferocious winter storms, helping to safely guide vessels to their ports of call.
Why did lightships have two massive mushroom anchors? Lightships were equipped with two enormous anchors that look a lot like giant mushrooms. Only one anchor was deployed at a time to maintain the lightship’s position on station.
If the anchor chain parted from the anchor and became separated from the lightship due to adverse sea conditions, the auxiliary anchor was deployed.
The main anchor weighed up to 7,800 lb, and the auxiliary anchor also was generally a mushroom anchor, except lighter, up to 6,500 lb.
The weight of the anchors was determined by the size of the lightship. Most US lightships displaced approximately 600 tons.
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