I recently picked up two early photographs of a caisson-type lighthouse under construction. Many images of this type of lighthouse structure exist but only occasionally do we find images of the process used to construct these lights. Easily seen in these images are the many iron plates that make up the structure as the workers work to rivet them together. Most times these towers were constructed on land to assure the fit of the pieces as seen here, and then disassembled and reassembled on site.
As early as 1838 in England, a new type lighthouse, the screw-pile, was constructed in an effort to provide a lighthouse on a shoal that would withstand the effects of ice and the sea.
By 1890, the design fell from favor as it proved too “delicate” for the harsh seas and winter conditions encountered here. By this time five screw-piles had burned or been damaged by ice in this country and they soon began to be replaced with a new style lighthouse - a caisson or “sparkplug style” (so called for its sparkplug-like appearance). Though still expensive, this style proved to be a cheaper, more efficient alternative to screw-pile lighthouses. They could better withstand harsh weather and were not as fragile. The first structure of this type was completed in the Delaware Bay at Fourteen Foot Bank in 1887 at a cost of $38,900.
Caisson foundations were best suited for unconsolidated bottoms composed of sand or mud. They incorporated a large cast-iron cylinder, which was constructed on shore and towed to the site, then sunk deep into the bottom and filled with rock and concrete to form a foundation. Where bottoms were harder, contained rocks, and/or needed greater depth of penetration into the substrate, the pneumatic process was used. The substrate within the caisson was removed and the caisson allowed to sink further into the bottom. The two-story keeper’s dwelling surmounted by the light tower was then built on top of the caisson foundation. Typically the station’s privy was cantilevered over the edge of the foundation cylinder permitting waste to drop directly into the water.
Generally speaking, the house was made of cast iron, although some brick examples are known.
Most caisson lighthouses were built at fairly exposed stations. Sometimes in the winter as ice floes built up and prevented any relief from reaching the station, keepers might be stranded at the station for months on end. The lighthouses proved very sturdy, and approximately fifty-nine such lighthouses with caisson foundations remain today.
Like our column?
for future subjects?
Please send in your suggestions and questions, or a photograph of an object that you need help dating or identifying. We will include the answer to a selected inquiry as a regular feature each month in our column.
Jim Claflin is a recognized authority on antiques of the U.S. Lighthouse Service, Life-Saving Service, Revenue Cutter Service and early Coast Guard. In addition to authoring and publishing a number of books on the subject, Jim is the owner of Kenrick A Claflin & Son Nautical Antiques. In business since 1956, he has specialized in antiques of this type since the early 1990s. He may be contacted by writing to him at 1227 Pleasant Street, Worcester, MA 01602, or by calling (508) 792-6627. You may also contact him by email: firstname.lastname@example.org or visit his web site at www.lighthouseantiques.net
This story appeared in the
November 2009 edition of Lighthouse Digest Magazine. The print edition contains more stories than our internet edition, and each story generally contains more photographs - often many more - in the print edition. For subscription information about the print edition, click here.
All contents copyright © 1995-2024 by Lighthouse Digest®, Inc. No story, photograph, or any other item on this website may be reprinted or reproduced without the express permission of Lighthouse Digest. For contact information, click here.