Some of the doors can be a right pain. keep a lump hammer and bailing wire in the hatch. got the bailing wire from one of the waste paper places. Handy for holding the doors back, if it’s long enough theres always something to attacjh it to.
I am with Dids on this, I pull out the 45 bumper bar to stand on, these bloody containers get no maintenance whatsoever… 
bugcos:
Couple of bungee cords do the trick, if the string have snapped off the doors, and there is nothing to hold them back. Found this out to me cost a few years ago. There was nothing to hold, the doors back with and I was backing up to a loading bay with the roller shutter door down.Can anyone guess what happened?Thats right the door swung round, but not to the side it went straight round and pointed out towards the door that I was backing up to. You shoulda seen the mess, it went straight through the roller shutter, god job no one was stood the other side
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I did the same nearly 4 years ago, I keep some knotted rope handy to keep the doors back since then.
A hammer ,some muscles and some determination usually does the trick with the stiff doors! 
Im 6’1 by the way
I always wondered why they didn’t put grease ■■■■■■■ in those hinge clap bits. Obviously they are going to corrode inside with sea spray getting in
Anyone remember the old seawheel boxs with doors at rear and all down one side.Due to having a heavy beam to support the doors they were heavy on one side.Had a few scarey moments going round r/bouts.