Hiko said.. I cruised for years with a store bought aluminium ladder with plywood hooks fitted to the top to go over the toe rail and two legs to hold it off the hull lower down It proved to be more comfortable to bare feet than the stainless one and we stored it along the rail when not in use It was long enough to extend into the water half a metre or so
Funny You said this. When i was in Bunnings I say these -
Fold out 3/4 of it straight, have the top 1/4 folded down so that it sits behind the toe rail, and fix to legs as you have said. This even gives you some ladder above the deck to hold onto.
Fold up and store below.
Dunno bout that one. Ladders that hook over the side usually have some supports that connect with hull. This would be hanging.