Hardtack
hard tack, hard bread, pilot bread
Hardtack (or hard tack) is a simple type of dense biscuit or cracker made from flour, water, and sometimes salt. hardtack is inexpensive and long-lasting. it is used for sustenance in the absence of perishable foods, commonly during long sea voyages, land migrations, and military campaigns. along with salt pork, hardtack was a standard ration for many militaries and navies from the 17th through the early 20th centuries.
Source: Wikipedia
:max_bytes(150000):strip_icc()/5865189-415019e21a164c6892a155e4e5e827ef.jpg)
