Sparkplug lighthouse
Encyclopedia
A sparkplug lighthouse, sometimes known as a bug light, is a type of caisson lighthouse
so named because of its shape. Generally speaking, a sparkplug lighthouse consists of a three-story living area, with the lantern on top; the whole is then placed upon a concrete
or metal caisson
. The superstructure was usually prefabricated and then lifted onto the caisson by crane. The classic sparkplug light sits in open water, with only the caisson below it and no dry land, but the term is also applied to lights on land or pierheads that are constructed in the same fashion.
Caisson lighthouse
A caisson lighthouse is a lighthouse whose superstructure rests on a concrete or metal caisson.Caisson lighthouses were developed in the late nineteenth century as a cheaper, more efficient alternative to screwpile lighthouses; they could better withstand harsh weather, and were not as fragile...
so named because of its shape. Generally speaking, a sparkplug lighthouse consists of a three-story living area, with the lantern on top; the whole is then placed upon a concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
or metal caisson
Caisson (engineering)
In geotechnical engineering, a caisson is a retaining, watertight structure used, for example, to work on the foundations of a bridge pier, for the construction of a concrete dam, or for the repair of ships. These are constructed such that the water can be pumped out, keeping the working...
. The superstructure was usually prefabricated and then lifted onto the caisson by crane. The classic sparkplug light sits in open water, with only the caisson below it and no dry land, but the term is also applied to lights on land or pierheads that are constructed in the same fashion.