Hi, Vernon!
What type of ladders/stairs do you want to know about? As you probably know, there are many types, depends upon the type of ship, the era it is from and what you are trying to access using them.
Typical modern ships use ladders/stairs with open risers and commonly have pipe-like handrails and stanchions. Check out a few of Barry's builds, and other constructions reports in the Ship Models topic, and see what they did. A number of the more recent kits (say, in the last 10 years or so) use a fairly well detailed construction method for the common ladders aboard ship, which use separate card parts for the steps, the side supports and then wire for building up the stancions and hand rails...others at times, particularly in the smaller scales, use a simple strip of paper onto which steps are drawn in.
Barry has used wire/solder to make up his ladder handrails/stanchions, as well as his railings. I tend to use glue soaked thread for the railings/stanchions, and card for the steps and side supports, but I am usually dealing with a smaller scale so I can get away with some of that slight of hand.
If you are looking for the hand ladders, such as those that run vertically up the side of a smoke stack, down into a cargo hold or up the rear of a gun turret, well, again, I'd have to say I've mostly seen those built up from wire in the larger scales, but I have also seen folks use ready made photoetched parts of this as well, both brass and in laser-cut paper.
If you have a particular ship in mind that you are working on or contemplating working on, telling us might help in getting some folks to give you ideas that you might find useful.
Cheers!
Jim
