Something in the 200-300mm range is usually adequate and can be lengthened by a teleconverter up to a 600mm. A good tripod is needed, especially if you want to use a telephoto lens. A good waterproof case is another must. One pesky grain inside your camera can cause nightmares. Shoot print film.
Prints are much easier to view and less expensive to process.
These little guys are easy to carry in the water due to their light weight and take unexpectedly good pictures. You'll want to get a good pair of swim fins and develop a keen knowledge of how and where waves break. We spent our free weekends going to Ventura looking for waves. Ventura and Pismo are probably the closest beaches to Bakersfield and have plenty of spots that are approachable for the novice surfer. The best advice I can think of to learn to surf and to take pictures of family and friends just starting out is to surf spots where the waves break slower and not so hollow.