The spar torpedo was invented during the American Civil War by E. C. Singer,[citation needed] a private engineer who worked on secret projects for the benefit of the Confederate States of America (Singer was the nephew of Isaac Singer, inventor of the sewing machine). Singer's torpedo was detonated by means of a trigger mechanism adapted from a rifle lock (see flintlock mechanism for a similar device). The spring-loaded trigger was detonated by means of a long cord attached to the attacking vessel. The attacking vessel rammed its target, embedding the barbed torpedo in its hull, then backed off. When the attacker reached the limit of the trigger cord, the torpedo was detonated.