Magazines : Designs : Frame and Fascine

Civil War Field Fortifications

Magazines

Theoretical Designs

Frame and Fascine Magazines

Scott's Military Dictionary offered a sketchy plan for a rather simple raised frame and fascine magazine which was apparently taken from a British manual on field fortification. This magazine defined its chamber using a series of parallel "A" frames formed from 9 x 12 inch scantling about eight feet long. The scantling members were joined (probably with an angled nailed butt joint) at about a 60 degree angle to form the head of the frame. Each frame was placed on scantling sleepers which were in shallow trenches about one foot deep along the longitudinal edges of the chamber. These sleepers were placed on undisturbed soil at an angle to receive the squared ends of the rafters flush. The trenches were filled and the soil rammed to help keep the rafters in place; the rafters were probably also held in place and in a vertical position by temporary battens since the design did not include a ridge post connecting and bracing the heads of the frames. This design produced a triangular shaped chamber with a maximum head clearance of about seven feet and maximum latitudinal floor clearance of about seven feet, six inches. Fascines in stacked tiers were used to line the exterior of the frames to form the combined roof and side walls and the whole was buried under a covering mass of earth to a depth of about three feet. A magazine constructed on this plan would not appear to have had sufficient surplus strength to withstand repeated artillery strikes on its covering mass, especially if hit along its length since the rafters did not have any lateral bracing and could be knocked out of their vertical position which would result in a fatal structural failure. Given the relative weakness of the chamber structure this magazine would have required extensive protection from enemy fire.

A second type of frame and fascine magazine was illustrated in Duane's Manual as an alternative to magazines with more substantial fully framed chambers. In this case the chamber was sunken and the frame formed in the manner of half a pitched roof with a kingpost joined to a ridgepost and supported by rafters which were set on a plate shelf inside the trench. The trench itself was given vertical slopes and was about 4' 9" deep, five feet wide at the top and four feet, plus the width of the kingpost, wide and the bottom. A shelf about one foot wide and two feet from the trench floor was formed on the unengaged trench wall to receive and brace the rafters. The scantling kingpost was about seven feet long and notched at the top to receive one-half the width of the ridgepost. It was set in a vertical position against the engaged trench wall on a plank or scantling plate. A ridgepost was laid in the notches at the top of the kingposts to form the head, or upper angle of the frame and the rafters, which were notched at the top, were joined to the ridgepost at a 45 degree angle. The shaped ends of the rafters were set against an "L" shaped plate formed of two planks. This design would produce a solidly braced interior chamber with an extreme head clearance of about 6' 6" and a floor width of four feet. Fascines were placed along the exterior of the frame to form the roof and interior wall of the engaged side. A row of gabions, which would be buried by the covering mass, was placed to buttress the vertically sloped fascines on the engaged side of the magazine. As usual, the structure of the chamber would be covered with multiple layers of rammed earth which could be made thicker on the roof and engaged side than on the unengaged side of the magazine. A magazine constructed following this design would probably have sufficient surplus strength to withstand artillery fire, but like the first frame and fascine design, the shape of the interior space of the chamber would have made handling heavy barrels of gunpowder a very laborious and backbreaking (literally) task.

<<< Previous Page | Next Page >>>

General Introduction to Magazines

Practical Designs

Magazine Failures

Rifle Pits Blockhouses Batteries

Back to Minor Works

Contents Home Page Major Works Siege Works Glossary

Mahan's Principles