The used Tornado rib I recently bought has a stainless ladder which is cantilevered from the A frame. It rotates about 180 deegrees so conveniently clips against the A frame, then can be unclipped and lowered into the water (swivels over the tube) when required. As its stainless it sinks vertically and tends to not float, hence no extra weight needed. You can climb the ladder and pull against the A frame. I only used it once, tend to pull myself over the tubes pulling on the bottle rack, but it seems to work fine. Wouldn't test it with all my scuba kit on though!