The shuttle carries the weft yarn through the warp threads to form the weaving. The clever thing about a boat shuttle is that the bobbin in the middle carries more yarn than an ordinary stick shuttle and the yarn feeds continuously as it rolls off the bobbin. The result is quicker, smoother weaving. And yes, it is a beautiful thing.
Looking at the pic--apart from noticing that I'm still having trouble with the orientation of my photos-- you can see that I've re-threaded my warp for a second sample. I've got an hour or so before I need to leave for class, so I'm going to work at it, as soon as I've had another coffee.