Star Fort

Also referred to as tenaille forts. A star fort was a detached enclosed fortification traced on the tenaille system with a pattern of alternating salient and re-entering angles. Star forts were generally categorized by the number of salients included in their traces or by the polygons produced by connecting their salients with an imaginary line; a star fort with six salient angles, for instance, was referred to as a hexagonal or six salient star fort. This type of trace represented an attempt to rectify the disadvantages inherent in the unflanked redoubt trace by adjusting the number, direction, and orientation of faces to produce columns of fire that crossed in advance of the re-entering angles and to provide for a degree of flanking defense of the ditch from the parapet of the enciente.

Star forts were used quite extensively in earlier wars, but had fallen out of favor after experience with the tenaille trace had proven quite disappointing during the Napoleonic Wars. Most nineteenth century engineering manuals had a good lot more to say about their disadvantages than their advantages and generally warned against the use of the tenaille trace for enclosed field works except in rare cases in which a specific site negated the trace's disadvantages and required its advantages. The litany of disadvantages was fairly long: flank defense of the ditch was ineffective, salients could only be defended by oblique fire, interior space was cut up by the re-enterings, the development of the parapet required a garrison too large for the area enclosed by the fortification, the salients were too vulnerable to enfilade fire and could not be protected by traverses without severely restricting the number of troops able to defend each face, and tracing a star fort on the ground and equalizing the deblai and remblai at the salients and re-enterings was too difficult and time consuming to be appropriate for most temporary field works. The advantage of the trace was, simply, that the combination of salients and re-entering angles allowed the garrison to cross its fire over ground in front of the re-enterings.

It should be noted that bastion fortifications are occasionally referred to as star forts, especially when laid out with a pentagonal trace with five bastions. Fort McHenry, at Baltimore, Maryland, for instance, is better known as a star fort than the pentagonal bastion fortification that the trace of its enciente indicates.

January, 2003

September, 2005