Add another gusty and mirthful success to the list of Harold Felton's entertaining tall tales. The exuberant chronicle of the exploits of Bowleg Bill, an eight- foot cowboy who rides herd on tuna fish and she- whales and he-whales, makes the most of two professions given to tall tales -- whaling and bronco-busting. The mixture of the jargon of the range and the poop-deck add to the incongruity of this beef-and-blubber comedy. Bowleg Bill sails out of Portland Harbor initially, under a Cape Cod skipper out to best a ""furriner"" captain from Plymouth in a race to San Francisco. When all else fails in a storm, Bowleg Bill saves Cape Cod's honor by riding herd on his cows astride the figurehead of a horse. These are spumy spoutings to regale readers or listeners in a family story circle. Prime, choice and Grade A. Bowleg Bill ranks with Felton's earlier Pecos Bill. William Moyers' foamy frothy sketches in aqua and black are added attraction to a pleasing format.