[gafftaper]

I've built many escapes using the following technique and the beauty of it is you can adjust it to fit just about any space. I don't see any reason you couldn't adjust it to use as a steep ships ladder either. Use two 2x8's as the sides of your steps. Secure the 2x8's to the back of the set and to the ground, parallel to each other. Cut 2x3 blocks and mount them on the inner edges of the 2x8's with a couple of 3" screws. These blocks are what your steps will sit on. Be careful about keeping them level to the ground, level to each other, and also about horizontal placement to evenly divide up the horizontal distance your steps are covering. Cut 2x8's to be steps... for a shallower stair I've used 2x6's in the past... I have the feeling this would work for you as well. Screw 2x8's down to the 2x3 bottom support blocks and also through the end from the outside of the main 2x8 beams with 3" screws.

I don't see any reason this basic technique couldn't work for you with some adaptations. For a hand rail I bolt some 2x4's to the sides of it and build a rail. That isn't going to work for you. I suggest you look at mounting some schedule 40 pipe in place perhaps. You need some serious hand rail.

Another alternative that just popped in my head would be to get yourself a 16' extension ladder, take it apart into two sections and attach it to the set so it can't move. That might be a lot safer still.