Rubberised or heavy nylon ponchos make a robust ground sheet on the beach or for sleeping under a tarp. In operations where ponchos are used, one is carried by each person, and when combined with another forms a two-person tent. Ponchos can be buttoned together as tarps or tents, and hiking poles can become tent poles. They are tough enough for use as an emergency shelter if need be.
Most army ponchos have grommet holes in the corners for use as a lean-to tarp or tent. You can get a poncho liner that ties to the grommet holes in the army ponchos and converts them to sleeping bags.
There are several nylon webbing tie loops on the corners and along the edges for versatile tarp set up.
Edges are fitted with light webbing tie loops and snap closures so it can be used as a tarp or turn it into a makeshift bivvy, pack cover or sleeping bag cover.
Get your poncho as big as you can, if you want to use it as a shelter. Multi-purpose ponchos offer decent rain protection when being worn or slept under.
Most army ponchos come in this standard size: