Stress
Work on a dredger can be boring and monotonous, and it also comes with a hopperful of stress. When a dredger is on a job, the deadline isn't, "Eh, whenever you guys can get around to it." The captain has been given a firm deadline, and he or she will want to hit it.
That means work never stops until the job is done. You might work twelve-hour shifts, which you and your fellow dredgers will split between day and night. And if a piece of equipment breaks down and work has to stop, that just adds to the pressure of meeting that looming deadline.
Depending on the job and the way the dredger is run, you may be able to go home after your shift, but you'll most likely live aboard the ship. Some crews work two to three weeks straight, then get the same amount of time off.
Sure, it's great to get that much down time, sort of like a mini-vacation, but remember that you'll still be spending a lot of time away from home. It's even tougher when you have a spouse and kids waiting for your return. Then again, after three weeks at home with the little monsters, you may look forward to your next stint on the dredger.