As a survey launch operator for USACE, I've often spent several days at a time standing by at a dock waiting for a tech to show up. After a major storm, I've surveyed 12 hours a day seven days a week for 6 plus weeks on end, plus travel time, piling up the overtime and some years, doubling my annual salary. My experience working in conjunction with hopper dredge leads me to believe their schedule might be more predictable. Hopefully, someone on this forum with direct experience can help answer that question better.
I spent years hopping from job to job looking for adventure and enjoying variety. I landed government work late in my working life. I found more deadwood and BS than in the civilian world but considering general job protection and benefits, I agree with Jimrr, it was a gravy train and one of the best decisions of my life as I got older and not quite so hell bent on adventure.