Frame Spacing

Warship design and construction, terminology, navigation, hydrodynamics, stability, armor schemes, damage control, etc.
Pandora
Member
Posts: 136
Joined: Sat Aug 27, 2011 1:40 pm

Frame Spacing

Post by Pandora » Sun Sep 25, 2011 10:49 pm

Most British and American battleships had a frame spacing of 4 feet that is 1.219 meters. Anyone knows what was the frame spacing of Bismarck, Yamato and others?
thanks

Pandora
Member
Posts: 136
Joined: Sat Aug 27, 2011 1:40 pm

Re: Frame Spacing

Post by Pandora » Tue Sep 27, 2011 10:24 pm

hello again,
I just read the frame spacing of Titanic was 36 inches amidships. If that is true how can a passenger ship have less spacing than a battleship?
Something is wrong somewhere I think.

User avatar
tommy303
Senior Member
Posts: 1527
Joined: Mon Oct 18, 2004 4:19 pm
Location: Arizona
Contact:

Re: Frame Spacing

Post by tommy303 » Wed Sep 28, 2011 12:30 am

It looks like the frame spacing on Bismarck averaged about 1m.

Their shoulders held the sky suspended;
They stood and Earth's foundations stay;
What God abandoned these defended;
And saved the sum of things for pay.

User avatar
Dave Saxton
Supporter
Posts: 2973
Joined: Sat Nov 27, 2004 9:02 pm
Location: Rocky Mountains USA

Re: Frame Spacing

Post by Dave Saxton » Wed Sep 28, 2011 2:37 pm

Pandora wrote:hello again,
I just read the frame spacing of Titanic was 36 inches amidships. If that is true how can a passenger ship have less spacing than a battleship?
Something is wrong somewhere I think.
How tight and heavy the framing needs to be on a battleship depends on several other factors. For example, what about the material qualities of the construction steel? Bismarck used ST-52 construction steel with much higher tensile strength, far superior ductility especially when cold, and resistance to corrosion, than the steel used by Titanic. It was also very weldable and didn't need to be rivitted to a frame work or use over lapping joints. It was also used for the most part (but not all) in 20mm thickness instead of the more common 12.5mm section thickness. This heavier section thickness in a welded structure required less framing to support it while attaining much greater overall strength. This actually attained over all weight savings per the strength making more weight available for protection, and armaments, and propulsion ect..
Entering a night sea battle is an awesome business.The enveloping darkness, hiding the enemy's.. seems a living thing, malignant and oppressive.Swishing water at the bow and stern mark an inexorable advance toward an unknown destiny.

Keith Enge
Member
Posts: 138
Joined: Sat Jan 01, 2011 1:36 am

Re: Frame Spacing

Post by Keith Enge » Wed Sep 28, 2011 11:12 pm

By frame spacing, I assume that you mean transverse frame spacing. The distance between frames really doesn't signify much about the ship. The frames exist to provide support for the ship's outer skin (and belt armor) and decks. If a ship has a thin skin like Titanic, you need a closer spacing to prevent "panting". Panting is the flexing of the skin due to water pressure working against it. If you have a thick skin, you can afford larger spacing and thus larger areas of unsupported skin. This method of construction is called transverse framing; closely spaced transverse frames are held in place by fairly sparse longitudinal girders.

The alternate method of construction is longitudinal framing. Here, you have closely spaced longitudinal girders held in place by sparse transverse frames. This method has the advantage of saving some weight and it is less rigid and so handles flexing of the hull girder better (hogging and sagging). However, it doesn't support heavy weights as well so transverse framing is needed in load bearing areas around turrets, etc. Most major warships are therefore a hybrid mixture of transverse framing amidships and longitudinal framing near the stem and stern.

So, all of this above explanation is just a long-winded way of saying that transverse framing spacing, considered totally separately, doesn't signify anything. It is only important as an integrated part of the construction method.

Pandora
Member
Posts: 136
Joined: Sat Aug 27, 2011 1:40 pm

Re: Frame Spacing

Post by Pandora » Thu Sep 29, 2011 7:37 pm

Thank you for your posts very informative.

by the way Titanic hull was 1 inch thick amidships. Quality could be poor but plate thickness seems to be ok or is 1 inch considered thin skin? Just for comparison how average thick was the plate of modern battleships?

Bill Jurens
Supporter
Posts: 358
Joined: Mon Oct 18, 2004 4:21 am
Location: USA

Re: Frame Spacing

Post by Bill Jurens » Fri Sep 30, 2011 2:54 am

For a variety of reasons you will generally find that the shell construction of merchant ships tends to be somewhat more robust than that of warships of similar size. Hood's side shell plating was typically 25#, about 0.625" thick, about the same at that used on the Iowa class ships and on Bismarck/Tirpitz; Yamato's plating was around 1/2" thick. In fairness, some of this -- but by no means all -- was often of somewhat higher strength than than used in merchant vessels. Along similar lines, in general, warship frame spacing was typically somewhat larger that that used in comparably-sized merchant ships.

This is a very brief summary only -- a complete treatment of the reasons, etc. would (and has) required a book-length treatment.

Bill Jurens

User avatar
José M. Rico
Administrator
Posts: 859
Joined: Sat Oct 16, 2004 10:23 am
Location: Madrid, Spain
Contact:

Re: Frame Spacing

Post by José M. Rico » Fri Sep 30, 2011 10:18 am

I think you should also keep in mind that WWII battleships had a double hull unlike Titanic single plate layer.

Keith Enge
Member
Posts: 138
Joined: Sat Jan 01, 2011 1:36 am

Re: Frame Spacing

Post by Keith Enge » Sat Oct 01, 2011 2:57 am

Jose - Some had a double or even triple bottom but not a complete double hull.

User avatar
José M. Rico
Administrator
Posts: 859
Joined: Sat Oct 16, 2004 10:23 am
Location: Madrid, Spain
Contact:

Re: Frame Spacing

Post by José M. Rico » Sat Oct 01, 2011 2:52 pm

Keith, take a look at this detailed drawing of Royal Oak midship section to see the double hull.

Image
http://www.hmsroyaloak.co.uk/construction.html

In Titanic the double bottom did NOT go all the way to the ship's sides.

Post Reply