There is a lifeguard tower next to the courts where we play so that would make for a better image or background then a volleyball. Those that play with us would recognize it,
http://www.palosverdes-beachcities-homes.com/wp-content/uploads/2012/06/22nd-street-lifeguard-tower.jpg
The letters in the logo should be the same size, the 4 doesn't need to be enlarged. However, the letters over a larger 4 in the background could work.
Although we play on the beach, sand and ocean are not needed in the logo.
Overall, a simple design is preferred over something detailed or photographic. The image will be used mostly on t-shirts and other apparel, not as much digitally and not at all in print.