rivets vs. welding {hull strength comparison}

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Hello All: I am posing a question for discussion that may or may not have been discussed here before. I know that the hull plates of the Titanic were riveted, overlaping, together. Had the technology existed in that day, would she have been able to withstand the impact with the berg if her hull plates had been welded? In riveting the hull plates, I believe the structural integrity of each plate was compromised where so many holes had to be drilled for the rivets. I think that a welded hull would have been more "elastic" and would provided more of a "bumper" effect than the catastropic results that did occur. So what are your thoughts on this?

Regards, Peter

-- Peter Nivling (pcnivling@capecod.net), May 31, 1998


Hi Peter,

Well, certainly a welded hull, such as the QE2 has, would not have the problem of rivits being broken off and creating holes in the ship where they had been holding the plates together. Whether that alone would have saved Titanic isn't clear to me.

My guess is that what matters most is the quality of the steel used. I doubt that welding would save a ship if the steel was of no better quality than the stuff on Titanic. I haven't studied metallurgy, so I can't comment on modern steel's "elastic" properties, though. The modern combination of good steel, welded hulls, and double skins is probably the best bet for staving off catastrophe in most cases; of course the Titanic wasn't "most cases".

-- Thomas Shoebotham (cathytom@ix.netcom.com), June 01, 1998.

Hello Thomas: My thought was that the weld is usually stronger than the material (the plates) itself. If the shearing of the rivets actually happened, I don't believe it happened from the berg shearing off the heads of the rivets, but was from the force of the plates buckling as she bounced along the berg, thereby "popping" the rivets through the plates. The quality of the steel, or iron, of the ship's hull has been questioned fairly recently, and no doubt, that would be a factor. Seems to me though that if the damage was done by the plates breaking from their fastenings, it was due to the inward force and the rivets and the plates not being up to the impact because they were weak where the rivets were placed. I would like to know if the recent scan on the hull below the mud line where the damage is revealed shows exactly what kind of damage was done. This scan put to rest the "300 foot gash" theory that has existed for years but did not really detail the actual damage other than to say it was a series of holes that amounted to 12 square feet of damage in total. I just can't imagine something such as an iceberg piercing the actual plates, despite the question of the quality of the material they consisted of. Just thinking outloud again, which I tend to do about the "T"! Regards, Peter

-- Peter Nivling (pcnivling@capecod.net), June 01, 1998.

Hi, Peter and Tom:

I think welding the plates might well have helped prevent at least some of the opening of seams in the hull plates. Kind of like the difference between stapling sheets of paper together and gluing them together. If you remove the staples, the sheets come apart easily, whereas if they're glued together, it takes a lot more force to separate them.

The rivets are very much like staples; they hold the sheets of steel together by sheer pressure. The force of the collision undoubtedly caused a number of them to pop or shear off. Once that happened, there was nothing to hold the plates together, so they began to separate; the pressure of the berg against the hull accelerated this process. If the plates had been welded, undoubtedly some welds would have failed, but I don't think you'd have seen the wholesale failure that actually occurred.

Just my nonscientific $.02.

-- Kip Henry (kip-henry@ouhsc.edu), June 01, 1998.

Just a couple of quick questions: What did they use to seal the joints between the plates when they riveted them? Or were the joints so tight that they needed no waterproofing? Thanks in advance for any enlightenment...

-- (foo@bar.com), June 02, 1998.

Check out the following article Repair Techniques of Riveted Vessels


From a cursory reading of the article, it appears that the main reason for the change from rivets to welds in naval construction is the amount of labour involved: it seems to be faster to weld a steel hull together.

-- Thomas M. Terashima (titanicShack@yahoo.com), June 02, 1998.

Hi Thomas:

Welding was not only less costly in manpower, but in materials. I recall reading somewhere of the US battleship West Virginia, which took three or four torpedoes at Pearl Harbor and sank. The ship was refloated, patched up, and returned to the West Coast for extensive repairs. As part of the repair work, the USN removed **all** her hull rivets, and welded the plates back in place. The weight of the rivets removed was so substantial that the ship actually stood several inches higher in the water!


-- Kip Henry (kip-henry@ouhsc.edu), June 02, 1998.

Riveted joints were designed back in those days along strict guidelines. Typically, they would be designed to develop the full tested strength of the material joined.

As for all the holes weakening the meta at the joint, the hole pitch (spacing) was carefully calculated based on the thickness of the metal, and the tested strength of the material joined. To make a joint stronger, the plates would be overlapped a greater distance, and multiple rows of properly pitched rivets would be employed. This would ensure plenty of material between the rivets to develop maximum strength.

You have to remember that the engineers probably did not design the hull to be dragged across an ice burg with the forces involved in the collision. (consider the forces involved, it took nearly 45,000 horse power just to make the ship move at 22 knots, making a ship that large tremble as it did as it scaped the ice burg would have been a considerable amount).

-- Wes K (wkinsler@wkinsler.com), March 30, 2004.

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