We have used duct tape to keep it open on the first boat and the second boat had a nice latch. You don't want a door slamming uncontrolled.

As for sailing, we sailed almost everywhere without motoring, except 2 times I got tired of tacking and motored in the last bit of the trip. The best we could get it to sail upwind was about 50 degrees apparent. We could sail at 7 to 8 knots most of the time on most points of sail.