Designed by jerry dunlap, the 1/4-scale crackerbox is a wooden scale model of an almost flat-bottom racing boat. powered by a zenoah g-23 marine gas engine, it can. Find best value and selection for your dumas 1439 crackerbox boat plans search on ebay. world’s leading marketplace.. Welcome to montgomery model boat clubs (mmbc) newest class of racing boats, the crackerbox! in an effort to attract more members and still operate the club in a fun.