There is absolutely no reason to throw the entire Labor Day weekend irretrievably out to sea, along with a variety of expensive lures. Nevertheless, every year more than half a million wet, cold, frustrated and deliriously happy surf casters leave their dry, warm homes to do so. They are sneered at by wives, beset by dogs, lifeguards, bathers, policemen and other surf fishermen onto whose turf they have blundered. Despite oceans of money spent on equipment ($150 for a decent outfit), no one ever catches anything. Near the big cities, where many insist on fishing, an occasional striped bass wanders along, but generally nothing more attractive than a surly skate or baby stingray shows up. A typical case is that of Robert Martin (below) of Los Angeles. He netted nothing from the bizarre cast shown here, more or less aimed into the surf at a place with the appropriate-sounding name of Point Dume, Calif.