It is not clear from the 12 negatives in this box if this is 1947 or 1948 academic year. Neither Naranjado 1947 or 1948 covers water polo images.
Joel does manage to get some good action shots. And while nothing is happening in the pool, he’s active in the surrounding area.
Next images were most likely taken the same day, but are not related to water polo as far as I can tell.
At the current rate of photographing, Joel may be very well shooting all the sport events at COP for his portfolio. There are quite a few more negative boxes to explore with COP/SJC attribution.