Timpani
Like the marching mallet percussion, timpani were marched first when drum corps required everything to be marched. However, the timpani were used prior to mallets.
The marching timpani were made of fiberglass, and were played by a four or five man line (similar to a modern day bass drum line). The timpani were cranked by a handle sticking up on the side of the drum. Sometimes intricate, complex music was made using the possibilities of 4 or 5 players. While one man was cranking/tuning, another was playing. To help tuning problems (which some corps had), corps sometimes used tuning gauges.
During concert pieces, timpani were often grounded momentarily, using a ti-pod leg system. Eventually around 1981, timpani and mallet instruments were allowed to be grounded in the front, paving the way to the modern day front ensemble. For a few years, corps still marched timpani. Some corps took advantage of the new rule, and grounded their timpani. However, some corps couldn't afford a new set of concert timpani, so they just grounded their marching timpani.
Harnesses for the timpani were originally just slings. Corps usually used 2 snare slings and hook them around the player, and onto his timpani. Some corps rigged wooden blocks between the drum and the player, to help balance issues, as the drums were carried high on the body. Some corps used harnesses for a few years, while some continued using slings.
Read more about this topic: Marching Percussion