Only the the keel was double plated.

Titanic had a double bottom, but the side was not doubled. I do believe that doubling the plating further up the side was one of the many things done in the very major and costly refit of the Olympic after Titanic had foundered.

Daniel

Oh I'm confusing the keel with hull. This is the dumbest question I'll ever ask. What is the hull again?

As regards rivets, I posted this on the THS group recently:

'Some anecdotal evidence as regards rivets comes from the annual
surveys and inspections that were carried out, by law, by the Board of
Trade when these liners' passenger certificates were issued. When we
are dealing with any vessel of this sort, over a long period -- as you
say -- there is inevitable wear and tear in terms of routine
maintainence. This involves the occasional caulking or renewal of
rivets and Olympic was no exception. Looking at these inspections for
Aquitania, Berengaria and Olympic in the early to mid-1930s, I don't
recollect any occasion where Olympic needed more than two hundred
rivets requiring attention; whereas with the two slightly younger
Cunarders -- and I am thinking here of Berengaria -- sometimes over
5,000 rivets required renewal or caulking. As I recall, the two
hundred rivets in Olympic's case were near the central propeller
aperture -- an area exposed to a great deal of stress in terms of the
hard service over twenty-four years.'

There's a lot of confusion about doubling. If you imagine the ship's hull (up to the underside of B-deck) as a structural girder, to obtain the necessary strength you need to mass material at the lower part of the girder (i.e. the keel, double bottom and turn of the bilge), and the upper part of the girder (i.e. the sheerstrake and strength deck). Amidships, Olympic and Titanic's plating at the sheerstrake level was doubled and generally two inches thick. The structure amidships is the strongest as the hull has to cope with sagging and hogging stresses, all while being driven through the most severe storms. Open spaces such as the reciprocating engine room have compensating strength in terms of additional and stronger pillars within the hull structure.

In terms of the double skin installed on Olympic and Britannic, in structural terms it wasn't really a continuation of the double bottom -- it did not add strength to the hull as the double bottom did. However, the double skin did add additional watertight protection and was probably the best that could be done with the existing hull.

Best wishes,

Mark.
http://www.markchirnside.co.uk

Thanks for the info mark, interesting!
Mac G, don't worry I'm always confuing bulkheads and bulwarks,
the keel is the "spine of a ship, and the hull the "skin". Thats the best way I can describe it. Here are two pictures, their different boats but they show what I mean. The first is the keel and the second the hull.

Attached file:   300px-Nachbau_Wikingerschiff_Roskilde.jpg (10.34 KB)

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okay it won't let me post two pictures at once so here's a picture of the hull.

Attached file:   180px-Hullform-3D.PNG.png (16.76 KB)

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Hi Rowan,

Thanks for the pictures.

Another interesting consideration is that the ships were designed to be docked on one line of blocks at the centre, so the hull structure was made strong enough to withstand that without the sides sagging down. The transverse watertight bulkheads -- much stronger than required by Lloyd's regulations, and with closer frame spacing -- were of considerable assistance in that regard.

Best wishes,

Mark.

Ahh I think I get what you mean Rowan. The keel would be what the men in the boiler rooms would be standing on. The bottom layer. And the siding of the ship(Part that the ice popped open) would be the hull?

Hi Mac,

Quote:

That's not quite true. The keel is only on the centreline, forming the ship's 'backbone' and key to the double bottom structure. The boiler rooms had their own floor plating, upon which stokers would stand and feed the furnaces with coal.

The hull structure includes the keel and double bottom.

Best wishes,

Mark.

Hmm...Alright. I think I get it. The Keel was laid down first, then the double bottom was added..The Hull? And then above that would be the bottom where anyone in the cargo holds, boiler rooms and engine rooms would stand on? I know there were pumping devices under where they stood.