Hi David, I don't know if there are any specific accounts of the smell or even if it was especially bad by the time the ship took on passangers. Attitudes being what they were at the time, they may not have given it much thought to something that would have a modern day health/environmental inspector throwing fits!
The ship was essentially complete on April 1st 1912, although there were a few minor things here and there that needed to be done. After nearly a fortnight, the fumes would have gone down to a level where at worst, they would have been a minor nuisence. The sticking point is whether or not there were strong fumes inside...which is possible if any touching up had to be done regardless of whether it was paint for metal or laquers/varnishes for the wood. Last minute touch ups are a fact of life in any shipyard, if only to fix something the buyer finds to be sub-standard.
You need primer for metal no matter where it's painted, inside or out because the topcoat doesn't have the adhesion qualities of the primer.
As a caveat to Rolf's remarks, even if you were covering the bulheads with panaling, you assuredly would need some kind of coating for the metal as the idea is to protect it from the corrosive effects of salt air. Paint does this, wood panaling can't.
Whether or not H&W actually did this much is something we could question. However, I've served on several ships that had false bulkheads over the real ones, and what was underneath always had some kind of protective coating. Without it, rust takes over with a vengence
Cordially,
Michael H. Standart