Pitch is like gears in your truck. It's a theoretical number of how many inches it travels for one revolution. Your prop in a perfect world would go forward 21 inches every turn it makes.
Now to make it confusing nobody can achieve zero slip so the fun starts. 12% is a good slip number for most bass hulls, really light and efficient boats like an Allison get a bit better.
Cup helps the prop work more efficient by grabbing a bit more water, especially when you start elevating the prop tips out of the water.
Now that all sounds pretty simple, right? It isn't. There's few really good prop guys that know exactly what they're doing, most can ruin that $500 wheel forever. Steve at fork is one of those few.
Some props beg for attention including but not limited to: all rakers, even pitch tempests, and lazers. It's amazing what a difference a skilled hand can make on them.
Marble Falls/Seadrift TX