What I know for sure is that in the discussion about the CS25, the designer stated explicitly that a minimum of 1-2" plus the whole thickness of the cleats was required on top. In the thread I linked to, people with more knowledge and experience than I stated what the standard requirements of stringers are. It's worth a read and those requirements have been gained from millions of boats. I also think that the CS25 shown was worse in that all four stringers were cut, and in a similar place. Early hull failure would have been certain with that boat and how it was going to be used. So it was rebuilt. I would agree that if the sole attachment is thick enough, strong enough, and well attached enough then it shouldn't matter. Which is why I'd be putting some structure on top there.VT_Jeff wrote: ↑Tue Apr 20, 2021 5:00 pmJust discussion for the sake of gaining knowledge at this point.OneWayTraffic wrote: ↑Mon Apr 19, 2021 7:35 pm I wasn't thinking about compressive strength at all. I'm willing to bet that that is solid, and far in excess of whatever force you apply standing on top of it.
I'm more thinking about the boat wanting to bend globally as it slams into or falls off a wave. That force is resisted by the stringers, that now have a hole near the top of them. That force will get focused into that cut out, by how much depends on just what section modulus is effectively left. I don't know enough about the precise situation to say anything for sure.
My impression:
I highly doubt Dan was referring to compression from walking, he was referring to the same compressive force you are: wave pounding, applying a force to the outside of the hull, which will be transferred, eventually to the cap/sole. In a I-Beam, the web component experiences sheer forces, the flanges bending forces. The sheer forces are distributed evenly throughout the web-depth, they are not concentrated at the top or bottom like in a "normal" beam. In a normal beam, the top and bottom experience tension or compression with a bending moment, the center neither, which is why holes need to be at the center. In an I-beam, it's not the case. A hole will weaken the web but the location of it, depth-wise, makes little-to-no difference.
As always, more than happy to be proven wrong, as my ONLY goal in this entire enterprise is to learn.
There are requirements about location and size in documentation building codes for pre made I beams. This one for example allows holes anywhere in the web at least 2mm from a flange, but the flange is 33mm thick. There are a lot of other requirements as well.
https://nzwoodproducts.co.nz/media/prod ... .2a_LR.pdf
Anyway I've said my piece, and a lot more than I originally intended too. Apologies for any derail from the build thread.