Micro holes in section frames above stringers. Steel hull

Hello everyone,

We’re currently working on a project to install coolant tanks between the section frames on a steel hull sailboat. During leak testing, we discovered small, pinpoint-sized holes in the bulkheads, located above the longitudinal stringers.

Does anyone know if these holes serve any functional purpose, or if they might simply be defects? If they don’t have any specific function, I’m like to welding them closed.

Thanks in advance for your help!

 

They are stress relief holes. That is an indication of a good construction.

 

As Gonzo notes above, such holes are used for stress relief.

However, the ones you show, are terrible. Since the hole is above the flat bar.
The hole should be like this:


The hole should start near the top of the flat bar to allow the welder to perform a return around the joint, thereby preventing the onset of a crack, owing to the stress concentration and biaixal stress field. .

What is shown, suggests to me that these mouse holes were not part of the original structure and it has cracked at the ends - since no relief hole is shown.
And as such, the hole is a crack arrester, as it has already cracked. Since there is a positive distance between the end of the FB and the lower edge of the hole:



The welding shown is pretty dire too, it is not a quality fabrication.

 

Hi.
Thanks for your answers and share your knowledge. If the hole is in wrong place i going to weld this.

 

Late to the dance, but Ad Hoc is correct. You should never have a 3 axis weld lines (i.e. x, y, and z) meet at a point; sure crack starter. Better to have the weld design Ad Hoc shows or ones similar to those detailed below in section 6.5 & 6.6. I concur with his thought that it is a crack arrestor.

Section 6 Construction details https://www.imorules.com/NSR_V1_PT6_CH6_5.html

 

At first sight they looked OK. However, seeing the enlarged photo it is clear the weld did not terminate correctly.