My understanding is this was done solely to improve the contrast of the hull against the dark gantry for photgraphic purposes. That way, the lines of the hull were sure to be recorded on film. There was no need to do the same for the second and third hulls of the class.
Often, important ships and the first of a class were white painted, especially for photographs. One example was the Oceanic of 1899, dubbed ‘the ship of the century.’
But black was used for hulls at the time when ships were in service, for practical necessity; among other things, corrosion caused by the sea air was much less noticeable on a black hull. Coal also made dirty marks on a white hull and didn’t show-up on a black one.
Photographs of the third sister painted white while serving as a hospital ship demonstrate this; the rust and coal dust show-up obviously. People sometimes refer to Britannic as a ‘rust bucket,’ but if you removed the black paint and camouflage from other liners of the time, they would look just as bad, if not worse.
Later, after oil-firing had been introduced to the liners, it was possible for white-painted hulls to be applied; Mauretania was given a white hull in the early 1930s when she was used for cruising, but there was still the problem of rust.
Did you ever see the Olympic in wartime dazzle paint with the nifty zigzags? Shades of grey and white- fabulous! I have a postcard of Britannic on the stocks in grey hull- nothing beats the black hull and gold stripe with white superstructure though!
I've seen photos of Olympic in her wartime camouflage; in fact, much of it was changed at various points during the war and some sources say it was altered at least four times! Some of the photos of her I purchased from the Imperial War Museum, and I have a colour postcard too. I am not sure if the postcard is accurate and I'm unsure of the exact colours offhand, I'll have to check this out.
In fact, if memory serves, Mauretania and Aquitania were also painted a greyish (slightly darker in their cases) at their launchings, but Lusitania was painted black. I'm no expert on those ships, though.
The photograph I have of the Aquatania at launch appears to be a very light grey. I have several of the Mauritania as well...thanks to the reprints of the Shipbuilder articals...which show the ship painted in much the same way.
All of the sources I have seen about Britannic's launch, including a newspaper article that I researched, described her hull as a dark grey. Where did the black colour information come from? I think the confusion is that this dark grey can look very close to black, especially in the old photographs. But if you compare some of them closely, there's a difference.
If memory serves, zinc (or another metal) plates are often fitted to hulls below the waterline, in addition to the more modern paints which are more defensive. Zinc (or whatever the metal is) is a more reactive metal than that of the ships’ hulls, so is more prone to corrosion; perhaps someone could confirm this, I’m no scientist!
Gray is a wonderful color for primer paint. Any color will go over it. And, if black is the intended top coat, a scratch in the protective outer coat will be immediately apparent. This makes preventive maintenance easier.
I haven't seen any references on the painting practices for 1911-era ships, but the need to prime the hull before topcoating may give a hint as to why the ships were launched a light color and then painted black. What is needed is a bit of paint chemistry sleuthing. What was the proper sequence of coatings in 1911? And what pigments, etc. were used?
As Parks says, nobody has found a way to prevent rust on steel ships. Many bulk freighters on the Great Lakes have traditionally been painted a rust red color, partly to hide rust. This color also hides the inevitable rusty stains caused by iron ore dust from the cargo.
Zincs are used below the waterline on ships to prevent galvanic corrosion caused by dissimilar metals. A ship like Titanic had several grades of steel (hull, propeller shaft, etc.) as well as bronze exposed to the water. These different metals can form a "battery" using the salt water as an electrolyte. The less noble metal corrodes fastest in this situation. The purpose of the zinc is to corrode instead of the more expensive parts of the ship. As the zinc corrodes, it is replaced to maintain protection.
David- yes- I too have always been under the impression that the gray was a primer coat. I have a postcard of the Britannic building in the gantry with the medium gray color (kind of a battleship gray, which I thought she was launched in before going to the fitting out docks for engines to be lowered through the top before the funnels and top structures were completed. I have always wondered if perhaps Titanic was launched "in black" because due to the Olympic-Hawke collision, crews were pulled off Titanic and sent to repair Olympic, and maybe there was extra time on hand before her launch ,while waiting , which was used to get her painted. I know on her interiors, several passengers have remarked on the smell of fresh paint in the corridors and staterooms- apparently there was a rush to make up for lost time and the work crews went down to the wire to meet the sailing date. Fascinating stuff. The theory about grey hull being more "photogenic" is all new to me. What is the source reference for this idea?
First of all, I was too hasty with my Britannic comment. Pulling out the pictures again, I am reminded that Britannic's hull was, in fact, a darker grey.
Titanic's hull was not painted black because of Olympic. Whatever colour the hull is painted for launch is a temporary one, as she will receive her final coats of paint alongside the fitting-out wharf. Work still has to be done to the hull, like putting on her name.
Now I am consumed with curiousity- not that it is of earth-shaking importance- but I wonder if White Star launched in black hull as a rule, or grey- and why, of the 3 was the Titanic the only Lady in Black. Experts out there? The Olympic repair theory is solely my own musing- not anything researched. Am now going into hiding till I have the answer!