For those who have "inherited" a trailer with a door that has a regular
house-type doorknob, Weiser makes one called a "WeiserBolt" that combines a
normal entry doorknob set with a deadlatching feature. Turning the inside
knob or handle when the latch is locked withdraws the bolt from its full 1"
deep deadbolt position to fully withdrawn in a normal twist of the knob or
handle.
The deadlatching feature is necessary on RV locks to make sure that road
vibration does not work the latch loose as is possible with a plain spring
latch.
Al