The Fog Signal

In Maine, where fog is a very common occurrence during the winter, keeping the fog bell ringing was just as important as keeping the lamp lit. During periods of heavy fog, the light was often useless and mariners relied on fog signals to navigate and avoid each other.

Spring Point Ledge Lighthouse was served by a 800-pound fog bell cast in Boston the year before the lighthouse was constructed and which was purchased for $180. The bell was suspended outboard of the railing of the upper gallery on the lighthouse’s east side. The bell was sounded by a sledge hammer operated by an automated Stevens Fog Bell machine, which was purchased for $300. An additional $100 was appropriated to set the machine up at the Boston Light Station for testing while the Spring Point lighthouse was being built.

The Stevens fog bell apparatus.

The Stevens fog bell apparatus.

The electric fog bell striker

The electric fog bell striker.

The Stevens Fog Bell apparatus was used in many lighthouses to ring a fog bell at a predetermined interval. The interval was determined by a set of cams and ratchets which made up the clockworks. A series of weights was suspended by a wire rope through the center column of the lighthouse. All the keeper had to do was keep the clockworks wound up. However, that was not as easy as it sounds because the weights could range from 200 to 800 pounds or more. These clockworks were advertised as good for 10,000 blows of the bell at one winding. The weights came in sections of 100 pounds each and the amount of weight applied determined the force with which the bell was struck. The Spring Point Ledge Light probably had a 200-300 pound weight. It is still in the center column in the cellar where it was dropped, along with the cable, when the Stevens fog bell apparatus was removed and replaced with an electric bell striker in the mid-1950s.

The weights in the center column.

The weights lie jammed in the center column, where they were allowed to drop when the Stevens fog bell apparatus was removed.

The fog bell on display at the lighthouse.

The fog bell on display at the lighthouse.

At Spring Point, the bell was struck two times every twelve seconds. Spring Point’s fairly rapid interval probably meant that the Stevens apparatus could go almost a full day between windings. The apparatus was set up in the watch oom with a series of levers and pivots extending through the wall to position the striker (sledgehammer) to hit the bell with enough force to bounce back into the cocked position. There was no spring cocking system. The 800-pound bell was strong enough to withstand such strikes.

Prior to the invention of mechanical bell strikers, the keeper was obliged to manually hit the bell with a sledgehammer for as long as the fog persisted. Needless to say, many keepers hated this difficult, monotonous task and often ‘forgot’ to ring the bell during long periods of fog. Fortunately, Spring Point’s keepers were never faced with this arduous task, as the Stevens Fog Bell apparatus was installed during the lighthouse’s initial construction.

When the lighthouse was electrified, it allowed a more automatic method of bell ringing. An electric solenoid mounted on the base of the bell support frame was timed to strike the bell on an interval. The only job required by the keeper, by this time a Coast Guardsman, was to turn it on when fog rolled in. It could even be controlled by remote control, so a keeper was no longer needed. This system was used for a number of years until the modern electro-acoustic “hooters” entered service.

Electro-acoustic fog horns

The electro-acoustic fog horns.

Spring Point Ledge Light now has two electronically-activated fiberglass fog signals controlled by an automatic fog detector which activates the fog horn when visibility drops to approximately one-half mile. This system works in both daylight and darkness and is effective in snow and rain as well as in fog. Because of their cylindrical shape, the electronic fog signals are jokingly called “R2D2s.”

The original fog bell is now on display on the upper gallery of the lighthouse.