Try an internet search for theater rentals or prop rentals  to find a rental company close enough to you.  We have a lot of good ones here in New York but that won't help you.....you might find that they want a substantial deposit for such items as a talking mechanical sailor.  We wanted to rent the umbrella gun for "Who's Afraid of Virginia Woolf" and the deposit was 2,000.00.  The transport of the spiral stairs might be very expensive.  You should talk to your local lumber yard or home supply center..they may have a cheap one.....600.00 - 800.00 that comes in a kit that you would have to assemble.....or if you get lucky you might be able to buy a used one.  By the time you rent a set of stairs and pay for transport it may make more sense to buy them.  They'll probably get used in more than one production.

We "faked" the laughing sailor for our production of "Sleuth."  We simply used a store mannequin, dressed like a sailor - complete with fake beard, and hinged the joints in the arms and neck.

It was set upstage against the flat and the prop was manipulated offstage by our ASM using wires and pulleys, like a large marionette.  On cue, the actor playing Andrew Wyke would "press a button" (also fake) while the Stage Manager played the sound cue of the laugh and the ASM tugged the pulleys.

No one in the audience noticed (or at least commented) that the mouth didn't move, as the sight of the sailor waving its arms and rolling its head back accomplished the effect admirably.

PS:  as an added inside joke, the "laugh" was actually the actor playing Andrew Wyke own dubbed voice.