Hull Fillet Welding Scallop fit up 5

[JohnKstk]

Dear Sirs,

I would to ask for your opinion about below case.
Material: Mild Steel Ship Building Grade A
Thickness: 12 mm, 20 mm
Welding: Full Penetration, Continuous Welding - Watertight - Working in underwater conditions

My question is: Do we need a scallop at the vertical 20mm stiffener??

 

[dhengr]

JohnKstk:
I think you should saute the scallops and eat them. Then hire someone who understands welding and weld design to actually design whatever that is. It is unlikely that the welds are going to be full pen. welds and it may be possible that they should not be all around, without some special attention to detailing. Show us some well proportioned sketches, with all the important dimensions, load conditions, etc. What is this thing, what does it do, how is it loaded? How could you possibly expect a meaningful response with so little meaningful design info? We can’t really see it from here, and the photo doesn’t help much.

 

[JohnKstk]

dhengr:
Your message is well received.
However the style of your message indicates that you try to disorientate the case and create a faulty impression. I fully understand welding and weld design but it is not allowed to give further information. This is typical ship building rules for fit up inspection. Anyhow thank you for your reply.

 

[DekDee]

JohnKstk,
I thought dhengr was actually quite polite in his response.
You have basically given no information and then asked for an opinion on something that should be addressed by the vessels designers - not by somebody random on an internet forum.
So, when the weld cracks and the ship sinks what will your defense be in a court of law ? - "But Sir, they told me it was OK on the eng-tips forum"!
Regards,
DD

 

[BUGGAR]

"Scalloping" the stiffeners makes it possible to get a continuous weld in the hull plate past the stiffener without the starts/stops. This should help you get a better weld. Welding stiffener legs is most efficient at their outer leg ends so the "scallops" are not detrimental to them.
You might be welding that ferry that Washington State just ordered and I could be riding it next year. That boat better not sink before I finish my beer!

 

[dieselofdog]

I have worked in a dock yard doing ship repair for a few years. I would always scallop out the gussets.

You need to read IACS No47. All the good info is contained in this code. All shipping classification societies use this as a base standard for repairs and new builds.

 

[JohnKstk]

Dear Sirs,

Thank you very much for your replies. All of them are highly appreciated. I always work with IACS Rules and i agree with dieselofdog and BUGGAR about scallops. DekDee i understand your point. The reason of this post is because i always have to fight with welding foremen since they are doing deep back-gouging at below shell plate instead of scallops. They just follow their WPS which never mention anything about scallops. I believe that this practice is not quality satisfactory. Plus i cannot find any official reference about this specific case (class rules etc). Definitely some things rise up from experience only but i would like to know if there is any specification or general rule (depending on gaps or thicknesses) about scallop in such cases. For your information this is a wake fin welded to the outer hull of a vessel and i am not the designer of this device.

Regards

 

[BUGGAR]

In my experience, the scallops should be specified in the design (as shown on the drawings), not the WPS. If a designer gives you a very restricted "rat hole" in the stiffener, the WPS may be modified to better suit welding through the hole but I see no need for a special WPS from your photo.
I don't know IACS rules, but I am considering AISC/AWS.

 

[bridgebuster]

Sometimes when you think you're getting scallops you're actually getting cod cheeks.