nitromethane43 wrote:...You can add an channel under the frame along with a series of drilled holes for a hitch pin or spring latch, the frame must be substantial enough to support the load without being pushed to the limit with holes drilled in it. ...
Yes, but fortunately if you keep the holes way from the top or bottom of the frame tube, they have very little effect on the strength (considering vertical loads) of the frame. Drill even 1/2" holes every inch or two along the centre line, and I wouldn't expect any problem - other than the rust at the holes and due to the water that come in them and sits in the frame. Drainage would be good...