Below is a picture from Vietnam 1966,
some DASF were deployed at Chu Chi with 25 Inf. 1st Div. 

These  2 guys filling our over head tank with water for showers where from 7th DASF Hawaii

A drum on top of the sandbags was the only hot water available to shower in and it was heated by sun.

ID'ed bottom right as  A2c Johnny Tolbert