Union troops digging a sap with a sap roller on Morris Island, 1863

Sapping is a term used in siege operations. Any trench excavated under defensive musket or artillery fire that was intended to advance a besieging army's position in relation to the works of an attacked fortification was referred to as a sap. Saps of approach were excavated by brigades of trained sappers or instructed troops of the line who advanced their sap under cover of a sap roller or mantlet by forming a parapet on the engaged side of the trench one gabion at a time and filling it with earth taken from the trench.

References

• Campell, E.S.N (1844). A Dictionary Of The Military Science:Containing an Explanation Of The Principal Terms Used In Mathematics, Artillery, and Fortification, And Comprising The Substance Of The Latest Regulations On Courts Martial, Pay, Pension, Allowances, Etc. A Comparative Table Of Ancient And Modern Geography; Achievements Of The British Army; With An Address to Gentlemen Entering The Army., New edition, London: James Maynard. Retrieved on 2007-11-19. 

• Ernst, O.H. (:1873). A Manual Of Practical Military Engineering, Prepared For The Use Of The Cadets Of The U. S. Military Academy, And For Engineer Troops.. New York: D. Van Nostrand. Retrieved on 2007-11-19. 

External links

• The Civil War Field Fortifications Website