I think my door situation is a little unusual. First, it's a normal "person size" rv door but it's on the rear of the trailer (I have a molded fiberglass body made by Li'l Snoozy, however mine is empty so I can haul cargo). Second, I use this trailer for work, making daily deliveries, so I don't have a choice not to use it when it's very windy. Third, due to the door's location a swirling wind can either push or pull the door, and sometimes it alternates pushing and pulling that door within as little as 5 seconds.
My current hold-back is like the #44855 on the page referenced by rockhillmanor. I'm fed up with it. I can imitate the wind by doing the pushing and pulling, and very easily duplicate the knob coming out of the slot. It is mounted so the prong swings sideways. If the slot piece is mounted with the opening to the driver's side, a push on the latched door will pop the knob out of the slot. So I reversed the slotted piece 180 degrees; now a pull on the door (wind pushing the door from the other side) pops the knob out. I have tried to envision how this might be remedied by mounting the pieces in the vertical position, but I can't picture how it would help... I will have to experiment a bit and see.
The page rockhillmanor posted does have a large variety. I have, in the past, had trailers with the plunger hold-back like the #46826, and with the metal T like the #46918, and I have had both of them also unlatch in strong winds. The plunger type was especially susceptible. The metal T wasn't too bad, but occasionally it would let loose, too.
The unit referenced by Chris Bryant might be very secure, but I think I've read that it takes two hands to latch and unlatch it. I need one hand just to hold the doggone door when it's blowing hard, and that only leaves me with one free hand (I'm not a mutant, lol). But I will have to see if I can look at one of these in person.
The bungee idea would be great for me, if I have something to tie it to. Closest thing is the bumper. Hmmm, food for thought.
Some of these Oklahoma wind gusts can run 45-50 mph. Pretty bad to work in, but work's got to be done. Thanks to all who've commented.
Mike G.
Liberty is meaningless where the right to utter one's thoughts and opinions has ceased to exist. That, of all rights, is the dread of tyrants. --Frederick Douglass
photo: Yosemite Valley view from Taft Point