Welded vs Riveted

[Dennis McGuckin]

Just reading. 'At all Costs', by Sam Moses.Basically about the convoys, especially to Malta. At one point in the book, there is a discussion about the merits of welded ships, against riveted.
The general consciences was that welded was stronger. My opinion was always the reverse. Remember some conversations aboard about it.Thought the Liberty Ships were just welded because it was quicker than riveting?

[Ivan Cloherty]

Having being involved in ship repair and new builds during my career I would say that welding is stronger than rivets, the weld is stronger than the steel it joins. The incidence of Liberty ships sinking frequently by breaking in half was due to a number of reasons, in prefabrication they never allowed for staggered strakes plate ends and the weld ran from port to starboard under the hull in one continuous line, this caused stresses in the steel adjacent to the weld, during WWII the steel production in the USA was a hurried affair and mistakes were made at some foundries during production resulting in brittle instead of flexible (elastic) steel being produced, although not a great deal of this brittle steel was produced enough was distributed to various yards for a myth to be born that welded ships were unsafe as more than one yard produced ships containing plates made from this brittle steel. It was only after WWII that this was discovered when it became imperative for shipyards to build with the welding process to be competative. Luckily many yards had plates left over from this era and there were subjected to modern metallurgical tests which showed that incorrect formulii had been used in production, no one was held to blame as rapidity of building sometimes over rode other tests that would be normal in peacetime. You may recall seeing on older ships especially Sam/Fort ships the words 'Kilroy was here' Well that was not a joke in reality, the ABS Surveyor called Kilroy in peace time used to tick worksheets to say that he had inspected a certain vessel, believe me these sheets are very detailed and time consuming, however during WWII Kilroy got exemption from the paperwork and was allowed to write 'Kilroy was here' on the parts of the ship that he had inspected and sign it, so another legend was born, other surveyors in other yards used the 'Kilroy was her' but signed their own names.

Rivets were used because no other methods were available at the time, so their use was never questioned, apart from them slowing down a building process they also had a disadvantage in service in that any weakness was hard to find especially in the area twixt loaded and light draughts were the rivet heads were subject to wear as the vessel ranged up and down the key, this weakness was accentuated as the plates worked in a seaway in rough weather with heads snapping off allowing water ingress into the holds, difficult to ascertain when hold full of cargo and strum boxes may have been blocked and water not showing in the bilge soundings. Rivets rarely gave trouble at the bow flare or stern which were not subject to quay abrasion. From my recent visit to ships it seems nothing has been learned about staggering strakes and plate ends as you still see a contiuous run from port to starboard under the hull, mainly because ships are built in different parts of the yard and then welded together and trying to herribone the plate ends would prove a too expensive exercise.

[Peter F Chard]

Ivan, Just brilliant -- you are excused washing the dishes tonight ! Also welding techniques have improved greatly as have the NDT ( non destructive testing ) controls now used. Also, welders are '' ticketed '', that is they have to meet certain standards of competency and be able to work to standards such as BS 5500 or ASME 8 codes Regards Peter in NZ.

[Ivan Cloherty]

Whoops! just noticed I put 'keys' instead of 'quays', go to back of the class dumbkoff

[Peter F Chard]

Ivan, You also incorrectly spelt ' continuous ' and ' herringbone' - I can see your school report now " Tries hard but must do better " Regards Peter in NZ

[Braid Anderson]

The WW2 Japanese battleships 'Yamato' and 'Musashe' - biggest battleships in history - were actually even heavier than necessary, if they had been built by the British or Americans. Purely because all important parts of the hull were riveted for safety. A result of the fact that Jap shipbuilders had big problems with welding, partly caused by inadequate welding rods.

[j.sabourn]

Can remember the repair technique to a rivet when a crack appeared in the steel adjacent to the rivet head was to drill a hole at the end of the crack to stop the spread of the crack, forget how you stopped the ingress of water however through the hole, maybe stick a piece of wrigleys spearmint in, the flavour not important. JS

[happy daze john in oz]

One of the problems with Titanic was the rivets used in her building. To save on cost iron rather than steel ones were used, they contracted in the cold water thus making the collision with the berg far worse than it needed to be.

[Ivan Cloherty]

Ivan, You also incorrectly spelt ' continuous ' and ' herringbone' - I can see your school report now " Tries hard but must do better " Regards Peter in NZ

Me mam also gave me a slap round the head for my inattention, but my excuse is I was watching television at the same time, for which I got another slap, just remembered! we didn't have a television when I was at school, must have been for something else!

[j.sabourn]

Trying to see what colour knickers the girls had on Ivan.,?? Hoping to find a liberated one. JS