Btw the drawing I'm working from is this, you can what I mean by its lack of clarity;
That is a very good drawing with a lot of information!
you can see where the engine is placed (many steam ship of this size tend to have a skylight above the engine room) and where the boilers a placed.
open bridge, life boat, open deck and closed decks.
Open decks just in front bellow the bridge and forward to bow. there is also an opening between thee 1. class salon and the engine room superstructure.
my suggestion is to get someone to that have Photoshop or gimp to scale the drawing for you. I can't since this computer don't have any! (Borrowed computer, my computer is to the doctor!). What that person need is the size of the boat.