I see you're using the latest in caribiner technology there.
I may be slow... But I sure am gimpy.
"Bless you child, when you set out to thread a needle don't hold the thread still and fetch the needle up to it; hold the needle still and poke the thread at it; that's the way a woman most always does, but a man always does t'other way."
Mrs. Loftus to Huck Finn
We Don't Sew... We Make Gear! video series
Important thread injector guidelines especially for Newbies
Bobbin Tension - A Personal Viewpoint
The location of the cracking is probably of bigger concern than the size. As it runs most of the length of the board and it is right next to your eye-bolt, it would be easy to split out and release the bolt.
As others have said, treated lumber or perhaps red-wood or cedar and let it age naturally into a beautiful finish.
We must, indeed, all hang together, or assuredly we shall all hang separately. - Ben Franklin
(known as a win-win on this forum)
It's oriented property. I think because the picture is so "head on", you can't see the sides.
As for the clamp....
My mom wanted to try out their hammock on my stand, but I only had one biner handy, so we used the clamp as a stand in.
And yes, this was one of the uprights I had notched. When I redo it, I'll make sure not to notch it too deeply this time.