Ground Plate 2 : A metal plate, usually 1/2 in. thick or more, placed beneath outrigger jacks to distribute the load; they are usually used on soft or unstable ground to stabilize an aerial or snorkel apparatus
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}