Parenn

When you go from small to large (i.e. from the power turning the inside of the gear to taking the power off the outside) you increase the speed (the teeth on the edge move faster over the ground than the edge of the axle) but lose torque. This torque loss means that there’s not enough to turn the axle leading to the hammer.
If you do the opposite at the top - feed the power into the vertical axle from the windmill via a large gear (i.e. put the windmill where you ave the angled gear in this image) it’ll cancel out, and in fact be more efficient since the vertical axle won’t be turning so fast and thus lose less energy.

Okay. It wasn't shadows
I found it would reliably crash when opening and closing a storage vessel multiple times (after 10-15s of holding the right mouse button down).
Once I could reproduce it I started removing mods.
It still crashed with no mods.
I tried a new world, placed a vessel and it didn't crash.
So, finally, I opened the game in recovery mode, and let it do its thing for a bit. Then I went back in, and it didn't crash (with no mods).
I added all the mods back, still no crash.
So, maybe try recovery mode for a bit?